VACUTAP® VR II III Maintenance Manual PDF

ON-LOAD TAP-CHANGER VACUTAP® VR II III (with VR I 2602) MAINTENANCE MANUAL 2343793/01 EN © All rights reserved by Maschinenfabrik Reinhausen Dissemination and reproduction of this document and use and disclosure of its content are strictly prohibited unless expressly permitted. Infringements will...

ON-LOAD TAP-CHANGER VACUTAP® VR II III (with VR I 2602) MAINTENANCE MANUAL 2343793/01 EN © All rights reserved by Maschinenfabrik Reinhausen Dissemination and reproduction of this document and use and disclosure of its content are strictly prohibited unless expressly permitted. Infringements will result in liability for compensation. All rights reserved in the event of the granting of patents, utility models or designs. The product may have been altered since this document was published. We reserve the right to change the technical data, design and scope of supply. Generally the information provided and agreements made when processing the individual quotations and orders are binding. The original operating instructions were written in German. Table of contents Table of contents 1 Introduction........................................................................................................................ 6 1.1 Validity................................................................................................................................................ 6 1.2 Manufacturer....................................................................................................................................... 6 1.3 Subject to change without notice........................................................................................................ 6 1.4 Completeness..................................................................................................................................... 6 1.5 Supporting documents........................................................................................................................ 7 1.6 Safekeeping........................................................................................................................................ 7 1.7 Notation conventions.......................................................................................................................... 7 1.7.1 Abbreviations used.............................................................................................................................................. 7 1.7.2 Symbols............................................................................................................................................................... 8 1.7.3 Hazard communication system............................................................................................................................ 9 1.7.4 Information system............................................................................................................................................. 10 2 Safety................................................................................................................................ 11 2.1 General safety information................................................................................................................ 11 2.2 Appropriate use................................................................................................................................. 11 2.3 Inappropriate use.............................................................................................................................. 11 2.4 Personnel qualification...................................................................................................................... 12 2.5 Operator's duty of care..................................................................................................................... 12 3 Monitoring during operation........................................................................................... 13 4 Product description......................................................................................................... 14 4.1 Function description.......................................................................................................................... 14 4.2 Setup/models.................................................................................................................................... 14 4.3 Type designation............................................................................................................................... 14 5 Scope of maintenance, maintenance intervals, dielectric strength of diverter switch oil and DC resistance measurement.............................................................................. 16 5.1 Scope of maintenance and maintenance intervals........................................................................... 16 5.2 Determining dielectric strength of diverter switch oil during operation.............................................. 16 5.3 Determining dielectric strength of diverter switch oil after maintenance........................................... 16 5.4 Measuring DC resistance on transformer......................................................................................... 16 6 Preparatory work............................................................................................................. 18 6.1 Safety precautions............................................................................................................................ 18 6.2 Providing auxiliary equipment........................................................................................................... 18 6.3 Moving on-load tap-changer to adjustment position......................................................................... 19 Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 3  Table of contents 7 Removing diverter switch insert.................................................................................... 20 7.1 Removing horizontal drive shaft........................................................................................................ 20 7.2 Lowering oil level in diverter switch oil compartment........................................................................ 21 7.3 Switching off supply voltage to tap-change supervisory control (if present)..................................... 22 7.4 Removing on-load tap-changer head cover...................................................................................... 22 7.5 Removing tap position indicator (version without multiple coarse change-over selector)................. 24 7.6 Removing tap position indicator from multiple coarse change-over selector with more than 35 oper- ating positions................................................................................................................................... 24 7.7 Removing tap-change supervisory control (if present)..................................................................... 26 7.8 Removing the oil suction pipe........................................................................................................... 28 7.9 Lifting out diverter switch insert......................................................................................................... 29 8 Maintaining on-load tap-changer................................................................................... 30 8.1 Cleaning and checking diverter switch oil compartment and oil conservator.................................... 30 8.2 Cleaning and inspecting diverter switch insert.................................................................................. 31 8.3 Inspecting coupling tube................................................................................................................... 32 8.4 Checking transition resistors............................................................................................................. 33 8.5 Replacing vacuum interrupters......................................................................................................... 34 8.6 Checking insulating shim.................................................................................................................. 34 8.7 Replacing varistor connection leads................................................................................................. 34 8.8 Replacing diverter switch insert........................................................................................................ 34 8.9 Replacing fixed main contacts.......................................................................................................... 34 8.10 Maintaining tap selector.................................................................................................................... 34 8.11 Cleaning and inspecting protective relay RS.................................................................................... 35 9 Inserting diverter switch insert....................................................................................... 37 9.1 Inserting diverter switch insert.......................................................................................................... 37 9.2 Inserting oil suction pipe................................................................................................................... 39 9.3 Inserting tap-change supervisory control (if present)........................................................................ 41 9.4 Inserting the tap position indicator without multiple coarse change-over selector............................ 43 9.5 Inserting tap position indicator with multiple coarse change-over selector with more than 35 operat- ing positions...................................................................................................................................... 44 9.6 Filling oil and securing on-load tap-changer head cover.................................................................. 45 9.7 Installing horizontal drive shaft.......................................................................................................... 47 9.8 Coupling on-load tap-changer and motor-drive unit.......................................................................... 48 10 Further checks................................................................................................................. 55 10.1 Performing trial tap-change operations............................................................................................. 55 10.2 Checking field of rotation.................................................................................................................. 55 10.3 Checking correct electric switch-off.................................................................................................. 55 4 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 Table of contents 10.4 Checking mechanical and electric end stop of on-load tap-changer/off-circuit tap-changer and motor- drive unit........................................................................................................................................... 55 10.5 Checking protective relay RS 2001, 2001/V, 2001/H, 2001/E, 2001/5, 2001/R, 2003...................... 56 10.6 Checking protective relay RS 2004................................................................................................... 57 11 Commissioning the transformer.................................................................................... 59 12 Appendix........................................................................................................................... 60 12.1 Maintenance schedule - required tasks............................................................................................ 60 12.2 Limit values for dielectric strength and water content of on-load tap-changer oil............................. 60 12.3 Tap-change process......................................................................................................................... 61 12.4 Switching sequence (742193)........................................................................................................... 62 12.5 VACUTAP® VRC/VRE, installation drawing (899992)..................................................................... 64 12.6 VACUTAP® VRD/VRF, installation drawing (899898)...................................................................... 65 12.7 VACUTAP® VR, adjustment positions (728557).............................................................................. 66 12.8 VACUTAP® VRC/VRE, adjustment plan without change-over selector (719853)............................ 67 12.9 VACUTAP® VRD/VRF, adjustment plan without change-over selector (721089)............................ 69 12.10 VACUTAP® VRC III/VRC II/VRE III, adjustment plan with reversing change-over selector connection (719850)............................................................................................................................................ 71 12.11 VACUTAP® VRD/VRF, adjustment plan with reversing change-over selector connection (721092)........................................................................................................................................................... 72 12.12 VACUTAP® VRG, adjustment plan with reversing change-over selector connection (727074)...... 73 12.13 VACUTAP® VRC/VRE, adjustment plan with coarse tap selector connection (719852)................. 74 12.14 VACUTAP® VRC, adjustment plan with multiple coarse change-over selector for change-over selec- tor division 10, 2-5 coarse tap connections (731412)....................................................................... 75 12.15 VACUTAP® VRC, adjustment plan with multiple coarse change-over selector for change-over selec- tor division 12, 2-5 coarse tap connections (731411)....................................................................... 76 12.16 VACUTAP® VRC, adjustment plan with multiple coarse change-over selector for change-over selec- tor division 14, 2-5 coarse tap connections (731410)....................................................................... 77 12.17 VACUTAP® VRC, adjustment plan with multiple coarse change-over selector for change-over selec- tor division 16, 2-5 coarse tap connections (731000)....................................................................... 78 12.18 VACUTAP® VRC, adjustment plan with multiple coarse change-over selector for change-over selec- tor division 18, 2-5 coarse tap connections (730977)....................................................................... 79 12.19 VACUTAP® VRD/VRF, adjustment plan with coarse tap selector connection (721091).................. 80 12.20 VACUTAP® VRG, adjustment plan with coarse tap selector connection (727075)......................... 81 12.21 Additional page VR for K applications............................................................................................... 82 12.22 Fax template..................................................................................................................................... 83 Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 5  1 Introduction 1 Introduction This technical file contains detailed descriptions on the safe and proper maintenance of the product. It also includes safety instructions and general information about the prod- uct. This technical file is intended solely for specially trained and authorized per- sonnel. 1.1 Validity This technical file applies to all the VACUTAP® VR® on-load tap-changers listed below, all of which can be supplied with and without change-over se- lector. ▪ Two-phase on-load tap-changer ▪ Three-phase on-load tap-changer ▪ On-load tap-changer combination (special version for delta connection, known as the K application) 1.2 Manufacturer The product is manufactured by: Maschinenfabrik Reinhausen GmbH Falkensteinstraße 8 93059 Regensburg, Germany Tel.: (+49) 9 41/40 90-0 Fax: (+49) 9 41/40 90-7001 E-mail: [email protected] Further information on the product and copies of this technical file are availa- ble from this address if required. 1.3 Subject to change without notice The information contained in this technical file comprises the technical speci- fications approved at the time of printing. Significant modifications will be in- cluded in a new edition of the technical file. The document number and version number of this technical file are shown in the footer. 1.4 Completeness This technical file is incomplete without the supporting documentation. 6 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 1 Introduction 1.5 Supporting documents The operating instructions for the following devices also apply in addition to this technical file: ▪ Drive shaft ▪ Protective relay RS ▪ TAPMOTION® ED motor-drive unit ▪ On-load tap-changer VACUTAP® VR I II III All documents form part of the scope of delivery. In addition, generally applicable legal and other binding regulations of Euro- pean and national law and the regulations for accident prevention and envi- ronmental protection in force in the country of use must be complied with. 1.6 Safekeeping This technical file and all supporting documents must be kept ready at hand and accessible for future use at all times. 1.7 Notation conventions This section contains an overview of the abbreviations, symbols and textual emphasis used. 1.7.1 Abbreviations used Abbreviation Definition OI Operating instructions DS Diverter switch DSI Diverter switch insert MC Main contact MR Maschinenfabrik Reinhausen GmbH MSV Main switching contacts (vacuum interrupter), main path MTF Transfer contact, main path OLTC On-load tap-changer TCIS Tap-change indicator sections TTF Transfer contact, transition path TTV Main switching contact (vacuum interrupter), transition path Um Highest voltage for equipment (in kV) CS Change-over selector MM Maintenance manual ZnO Varistor Table 1: Abbreviations used Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 7  1 Introduction 1.7.2 Symbols Symbol Definition Wrench size Tightening torque Number and type of fastening materials used Fill with oil Cut open, cut through Clean Visual inspection Use your hand Adapter ring Apply a coat of paint Use a file Grease Coupling bolt Use a ruler Use a saw Hose clip 8 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 1 Introduction Symbol Definition Wire eye, locking wire Use a screwdriver Table 2: Symbols 1.7.3 Hazard communication system Warnings in this technical file use the following format: WARNING Type and source of danger Consequences ► Action ► Action The following signal words are used: Signal Definition word DANGER Indicates a hazardous situation which, if not avoided, will result in death or serious injury. WARNING Indicates a hazardous situation which, if not avoided, could result in death or serious injury. CAUTION Indicates a hazardous situation which, if not avoided, could result in minor or moderate injury. NOTICE Indicates measures to be taken to prevent damage to property. Table 3: Signal words in warning notices Pictograms warn of dangers: Pictogram Definition Warning of a danger point Warning of dangerous electrical voltage Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 9  1 Introduction Pictogram Definition Warning of combustible substances Warning of danger of tipping Table 4: Pictograms used in warning notices 1.7.4 Information system Information is designed to simplify and improve understanding of particular procedures. In this technical file it is laid out as follows: Important information. 10 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 2 Safety 2 Safety 2.1 General safety information This technical file contains detailed descriptions on the safe and proper maintenance of the product. ▪ Read this technical file through carefully to familiarize yourself with the product. ▪ Particular attention should be paid to the information given in this chap- ter. 2.2 Appropriate use The product and associated equipment and special tools supplied with it comply with the relevant legislation, regulations and standards, particularly health and safety requirements, applicable at the time of delivery. If used as intended and in compliance with the specified requirements and conditions in this technical file as well as the warning notices in this technical file and attached to the product, then the product does not present any haz- ards to people, property or the environment. This applies throughout the pro- duct's entire life, from delivery through installation and operation to disas- sembly and disposal. The operational quality assurance system ensures a consistently high quality standard, particularly in regard to the observance of health and safety re- quirements. The following is considered appropriate use ▪ The product must be maintained in accordance with this technical file ▪ The equipment and special tools supplied must be used solely for the in- tended purpose and in accordance with the specifications of this techni- cal file ▪ The product must be used only with the transformer specified in the or- der 2.3 Inappropriate use Use is considered to be inappropriate if the product is used other than as de- scribed in the Appropriate use section. Maschinenfabrik Reinhausen GmbH does not accept liability for damage re- sulting from unauthorized or inappropriate changes to the product. Inappro- priate changes to the product without consultation with Maschinenfabrik Reinhausen GmbH can lead to personal injury, damage to property and op- erational disruption. Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 11  2 Safety 2.4 Personnel qualification The product is designed solely for use in electrical energy systems and facili- ties operated by appropriately trained staff. This staff comprises people who are familiar with the installation, assembly, commissioning and operation of such products. 2.5 Operator's duty of care To prevent accidents, disruptions and damage as well as unacceptable ad- verse effects on the environment, those responsible for transport, installa- tion, operation, maintenance and disposal of the product or parts of the prod- uct must ensure the following: ▪ All warning and hazard notices are complied with. ▪ Personnel are instructed regularly in all relevant aspects of operational safety, the operating instructions and particularly the safety instructions contained therein. ▪ Regulations and operating instructions for safe working as well as the relevant instructions for staff procedures in the case of accidents and fires are kept on hand at all times and are displayed in the workplace where applicable. ▪ The product is only used when in a sound operational condition and safety equipment in particular is checked regularly for operational relia- bility. ▪ Only replacement parts, lubricants and auxiliary materials which are au- thorized by the manufacturer are used. ▪ The specified operating conditions and requirements of the installation location are complied with. ▪ All necessary devices and personal protective equipment for the specific activity are made available. ▪ The prescribed maintenance intervals and the relevant regulations are complied with. ▪ Maintenance of the product may only be carried out by qualified and trained personnel in accordance with this technical file. ▪ Be sure to contact MR immediately in the event of damage during on- load tap-changer maintenance work. ▪ The operator must ensure appropriate use of the product. 12 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 3 Monitoring during operation 3 Monitoring during operation Monitoring the on-load tap-changer and motor-drive unit is limited to occa- sional visual checks of on-load tap-changer head, protective relay and mo- tor-drive unit. For efficiency reasons these visual checks can be combined with the usual checks on the transformer. Pay particular attention to the following: ▪ Oil impermeability at the sealing points of the on-load tap-changer head, protective relay and connected pipes ▪ Gaskets of the protective housing of the motor-drive unit ▪ Correct functioning of the installed electrical heater in the protective housing of the motor-drive unit ▪ Protective relay function test in accordance with respective operating in- structions ▪ Perfect condition of the silica gel breather for the on-load tap-changer oil conservator The insulating oils in the transformer, including the on-load tap-changer, are to be monitored by the operator following the appropriate rules and regula- tions. The oil quality of the on-load tap-changer oil should be checked at regular intervals: ▪ For on-load tap-changers used on the neutral point of windings (class 1 in accordance with IEC 60214-1): every 7 years ▪ For on-load tap-changers used at points other than the neutral point of windings (class 2 in accordance with IEC 60214-1): every 2 years To do so, proceed as follows: 1. Take oil sample from diverter switch oil compartment. 2. Record temperature of oil sample just after sample is taken. 3. Determine dielectric strength and water content at a diverter switch oil temperature of 20 °C ± 5 °C. The dielectric strength and water content must comply with the limit values provided in the appendix [► 60]. Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 13  4 Product description 4 Product description This chapter contains an overview of the design and function of the product. 4.1 Function description On-load tap-changers are used to adjust the desired tap of a tap winding un- der load. During the tap change operation the fine tap selector first selects the desired tap of the tap winding. The diverter switch insert then switches from the cur- rent-carrying tap to the preselected tap. During this tap change operation one tapping step of the tap winding is briefly bridged with an ohmic resistor so that the diverter switch operation can be carried out without any interrup- tion in current. The tap-change process for one step is shown in the appendix [► 61]. 4.2 Setup/models The on-load tap-changer consists of the on-load tap-changer head, diverter switch oil compartment with built-in diverter switch insert and the tap selector mounted below (also available with change-over selector on request). The standard model is available with on-load tap-changers without change- over selector up to a maximum of 18 operating positions and with change- over selector with up to a maximum of 35 operating positions. The design and designation of the most important on-load tap changer com- ponents are shown in the installation drawings in the appendix [► 64]. 4.3 Type designation The on-load tap-changers are available in several models. The type desig- nation of the on-load tap-changer therefore depends on the model hence ensuring an unmistakable and non-interchangeable on-load tap- changer designation. Example: VACUTAP® VRF III 1300 Y - 72,5/C – 10 19 1 G VACUTAP® VRF On-load tap-changer type III Number of phases 1300 Maximum rated through current (in A) Y Neutral point application 72.5 Highest voltage for equipment Um (in kV) C Tap selector size 10 Pitch of tap selector 14 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 4 Product description 19 Number of maximum operating po- sitions 1 Number of mid-positions G Change-over selector as coarse change-over selector Table 5: Type designation Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 15  5 Scope of maintenance, maintenance intervals, dielectric strength of diverter switch oil and DC resistance measurement 5 Scope of maintenance, maintenance intervals, die- lectric strength of diverter switch oil and DC resist- ance measurement We generally recommend having maintenance carried out by our Technical Service. If this route is taken, in addition to the correct performance of all work, certain components will be upgraded to the latest state of technology and manufacturing status. The maintenance can usually be carried out by qualified and MR-trained per- sonnel within one day per on-load tap-changer pole, provided it is well pre- pared and organized. If maintenance is not carried out by our Technical Service department, please ensure that the personnel who carry out the maintenance are trained by MR or are otherwise suitably qualified to carry out the work. In such cas- es, we would ask you to forward to us a report on the maintenance per- formed so we can update our maintenance files. You can use the fax tem- plate in the appendix for the report. For inquiries about spare parts, please provide the serial number (see name plate on on-load tap-changer head cover) and the number of tap-change op- erations (see operations counter on motor-drive unit). 5.1 Scope of maintenance and maintenance intervals Please refer to the maintenance schedule in the appendix [► 60] for the scope of maintenance and maintenance intervals. 5.2 Determining dielectric strength of diverter switch oil during operation Check the dielectric strength of the diverter switch oil in the diverter switch oil compartment. The dielectric strength and water content must comply with the limit values provided in the appendix [► 60]. 5.3 Determining dielectric strength of diverter switch oil after maintenance Check the dielectric strength of the diverter switch oil added after mainte- nance. The dielectric strength and water content must comply with the limit values provided in the appendix [► 60]. 5.4 Measuring DC resistance on transformer Note the measurement scenarios listed below and the associated maximum measured currents when measuring DC resistance on the transformer. 16 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 5 Scope of maintenance, maintenance intervals, dielectric strength of diverter switch oil and DC resistance measurement The measured DC current is normally restricted to 10 % of the rated current of the measured transformer winding in order to prevent the winding from overheating. DC resistance meas- DC resistance meas- urement in various urement in various on-load tap-changer on-load tap-changer operating positions operating positions without interruption with interruption of of measured current measured current during the change of during the change of operating position operating position (the measured cur- rent must be 0 A when changing oper- ating position) Oil compartment emp- Maximum 10 A DC Maximum 50 A DC ty Oil compartment filled Maximum 50 A DC Maximum 50 A DC with insulating oil Table 6: Maximum permitted measured currents when measuring DC resistance on transformer Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 17  6 Preparatory work 6 Preparatory work Perform the following work before starting maintenance. 6.1 Safety precautions WARNING Danger of death and severe injury! An energized transformer and energized on-load tap-changer components could cause death or serious injuries during maintenance work! ► Adherence to the following safety precautions is mandatory. 1. Switch off transformer. 2. Lock transformer to prevent unintentional restart. 3. Make sure everything is de-energized. 4. Visibly connect all transformer terminals to ground (grounding leads, grounding disconnectors) and short circuit them. 5. Cover or cordon off adjacent energized parts. 6.2 Providing auxiliary equipment Provide the following auxiliary equipment for on-load tap-changer mainte- nance: ▪ Oil pump for performing an oil change ▪ Brush and highly-absorbent, lint-free cleaning rags ▪ Working table ▪ Oil sump ▪ Tool ▪ Clean empty barrels and transformer oil for cleaning and oil change in accordance with following table (the oil quantity depends on the on-load tap-changer type and its rated voltage Um). OLTC variant Highest voltage for equipment Um [kV] 72.5 123 170 245 300 362* VRC 155 175 190 210 235 VRD, VRE, VRF, VRG 175 195 210 230 255 280 * for VRF/VRG only Table 7: Oil quantity for oil change (stated in liters) ▪ Crane or MR lifting device (maximum weight of diverter switch insert 120 kg) OLTC variant Highest voltage for equipment Um [kV] 72.5 123 170 245 300 362* VRC 1120 1250 1350 1450 1580 18 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 6 Preparatory work VRD, VRE, VRF, VRG 1250 1380 1480 1580 1710 1840 * for VRF/VRG only Table 8: The withdrawal height of the diverter switch insert during maintenance (stat- ed in millimeters) 6.3 Moving on-load tap-changer to adjustment position NOTICE Damage to the on-load tap-changer and transformer! Damage to on-load tap-changer and transformer if motor-drive unit is oper- ated when not coupled! ► Never operate the motor-drive unit while the on-load tap-changer and motor-drive unit are not coupled. ► As a precaution, block the motor-drive unit against electrical operation by actuating the motor protective switch (see operating instructions for "Tapmotion® ED"). 1. Move on-load tap-changer to adjustment position. Figure 1: Adjustment position 2. Write down the current operating position of the on-load tap-changer. Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 19  7 Removing diverter switch insert 7 Removing diverter switch insert 7.1 Removing horizontal drive shaft 1. Loosen hose clips on guard plate of horizontal drive shaft, remove guard plate. Figure 2: Removing guard plate 2. Depending on version, loosen 4 or 6 screws on coupling brackets to up- per gear unit and bevel gear. Figure 3: Loosening coupling brackets 20 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 7 Removing diverter switch insert 3. Remove horizontal drive shaft. Be sure not to lose the coupling bolts. Figure 4: Removing drive shaft 7.2 Lowering oil level in diverter switch oil compartment Before removing the on-load tap-changer head cover, the oil level in the diverter switch oil compartment must be lowered. WARNING Danger of death or severe injury! Danger of death or severe injury from explosive gases under the on-load tap-changer cover, in the pipework system, in the oil conservator or at the dehydrating breather opening! ► Ensure that there are no naked flames, hot surfaces or sparks (e.g. caused by static charging) in the immediate surroundings and that none occur. ► Observe applicable fire protection regulations. 1. Remove screw cap on air-vent valve E1 on the on-load tap-changer head cover. Figure 5: Screw cap 2. Use screwdriver to lift valve tappet on air-vent valve E1 until oil starts to come out. Figure 6: Valve tappet Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 21  7 Removing diverter switch insert 3. Close stop-cock between oil conservator and on-load tap-changer. 4. Place a bucket (10 l) under the drain valve of the on-load tap-changer to collect the drained oil. 5. Open drain valve. 6. Use screwdriver to lift valve tappet on air-vent valve E1. The oil level falls automatically. Figure 7: Valve tappet 7. Once approx. 10 l of oil has been drained, close drain valve and seal air-vent valve E1 with screw cap. 7.3 Switching off supply voltage to tap-change supervisory control (if present) If the on-load tap-changer is fitted with a tap-change supervisory control, the tap-change supervisory control must be de-energized before the head cover is opened. 1. De-energize tap-change supervisory control. 2. Make sure everything is de-energized. 7.4 Removing on-load tap-changer head cover WARNING Danger of death or severe injury! Danger of death or severe injury from explosive gases under the on-load tap-changer head cover! ► Ensure that all auxiliary circuits (e.g. tap-change supervisory control, pressure relief device, pressure-operated relays) are de-energized. ► Do not operate any electric devices (e.g. impact wrench, risk of sparks) during the work 22 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 7 Removing diverter switch insert 1. Loosen screws with locking washers on the on-load tap-changer head cover. Figure 8: On-load tap-changer head cover 2. NOTICE! Remove the on-load tap-changer head cover. Check that the sealing surfaces on the on-load tap-changer head cover and on-load tap-changer head are in sound condition when removing and during all other work. Ensure that o-ring is in sound condition also. Ensure that parts do not fall into the diverter switch oil compartment. Parts in the diverter switch oil compartment may block the diverter switch insert, thereby damaging the on-load tap-changer and transformer. Check that you have the same number of parts when disassembling and reassem- bling. Figure 9: On-load tap-changer head cover with o-ring 3. Remove the remaining oil from the diverter switch oil compartment via the pipe connection S. Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 23  7 Removing diverter switch insert 7.5 Removing tap position indicator (version without multiple coarse change-over selector) ► Pull the spring clip off the shaft end and remove the tap position indica- tor disc. Figure 10: Tap position indicator disk 7.6 Removing tap position indicator from multiple coarse change-over selector with more than 35 operating posi- tions 1. Ensure that the red marks on the panel, tap position indicator disk and cover disk produce a continuous red line. 2. Remove countersunk head screw. Figure 11: Countersunk head screw 24 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 7 Removing diverter switch insert 3. Lever cover disk off underlying disk with flat screwdriver and pull out po- sition-indication disk from between panel and bracket. Figure 12: Cover disk and position-indication disk 4. Remove hexagon screws and associated lock tab. Figure 13: Lock tab 5. Pull panel and bracket up and off indicator drive shaft. Figure 14: Panel Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 25  7 Removing diverter switch insert 7.7 Removing tap-change supervisory control (if present) NOTICE Damage to the on-load tap-changer and transformer! Removing the tap-change supervisory control without due care may dam- age it, thereby resulting in damage to the on-load tap-changer and trans- former! ► Remove tap-change supervisory control with care in order not to dam- age or rip out the connecting leads. 1. Take tap-change supervisory control plug connector out of bracket and disconnect. Figure 15: Plug connector 2. Remove nuts and locking elements (3 or 4 depending on model) on the mounting plate. Figure 16: Mounting plate with nuts and locking washers 26 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 7 Removing diverter switch insert 3. Remove the tap-change supervisory control together with the mounting plate and drive shaft. Figure 17: Tap-change supervisory control with mounting plate and drive shaft 4. Remove nut and Teflon strip from stud bolt. Figure 18: Stud bolt with Teflon strip and nut Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 27  7 Removing diverter switch insert 7.8 Removing the oil suction pipe 1. Remove cable ties from the oil suction pipe. Figure 19: Cable tie 2. Pull oil suction pipe out of on-load tap-changer head. Figure 20: Oil suction pipe 3. Swivel lead of tap-change supervisory control out of on-load tap-chang- er head in direction indicated by arrow until the cable will not be dam- aged when the diverter switch insert is pulled out. Figure 21: Swiveling out tap-change supervisory control lead 28 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 7 Removing diverter switch insert 7.9 Lifting out diverter switch insert 1. By turning the coupling tube on the upper screening ring, align it in such a manner that the triangular marks on the on-load tap-changer head and those on the coupling tube match up. Figure 22: Aligning the coupling tube 2. Insert the lifting gear in the eyebolts of the coupling tube and position vertically above the diverter switch insert. 3. Lift the diverter switch insert slowly and vertically out of oil compartment. Figure 23: Diverter switch insert 4. CAUTION! Place the diverter switch insert on a level surface and secure it against tipping. An unstably positioned diverter switch insert may tip, resulting in injuries and damage. 5. NOTICE! Neither operate the diverter switch insert while removed nor change the position of the tap selector coupling.Otherwise, the diverter switch insert may be damaged when being reinstalled. Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 29  8 Maintaining on-load tap-changer 8 Maintaining on-load tap-changer The on-load tap-changer must be maintained after every 300,000 switching operations. Proceed as follows to do this: NOTICE Damage to the on-load tap-changer and transformer! Damage to the on-load tap-changer and transformer from used fixtures and gaskets! ► Only use lock tabs, lock disks, lock nuts and the on-load tap-changer head cover o-ring once and replace once removed. ► Only use self-locking screws with thread coating with micro-encapsulat- ed adhesives once and replace once removed. Note expiry date of new parts. ► Ensure that screw connection points and elements are free of oil and grease. 8.1 Cleaning and checking diverter switch oil compartment and oil conservator Cleaning diverter switch oil compartment and oil conservator Proceed as follows to clean the diverter switch oil compartment and oil con- servator: WARNING Danger of death or severe injury! Danger of death or severe injury from explosive gases under the on-load tap-changer head cover, in the pipework system, in the oil conservator or at the breather opening! ► Ensure that there are no naked flames, hot surfaces or sparks (e.g. caused by static charging) in the immediate surroundings and that none occur. ► Use pumping equipment and hoses approved for flammable liquids. ► Only clean with transformer oil. 1. Open stop valve located between on-load tap-changer head and on- load tap-changer oil conservator. 2. NOTICE! Only rinse on-load tap-changer oil conservator with new transformer oil. Other cleaning agents may cause damage to the on- load tap-changer and transformer. 3. Use an oil pump to pump all the oil out of the diverter switch oil compart- ment. 4. Make sure the oil compartment is completely drained. 30 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 8 Maintaining on-load tap-changer 5. NOTICE! Clean diverter switch oil compartment and on-load tap-chang- er oil conservator using only new transformer oil and absorbent, lint-free cleaning cloths. Other cleaning agents may cause damage to the on- load tap-changer and transformer. Avoid damaging the inner surface of the oil compartment and the contacts fitted there. 6. Check the oil conservator breather of on-load tap-changer and replace the drying agent if necessary. Checking diverter switch oil compartment Proceed as follows to check the diverter switch oil compartment: 1. Check fixed oil compartment contacts and inside of diverter switch oil compartment using a mirror and lamp. The silver coating on the con- tacts must not be discolored. Figure 24: Oil compartment contacts 2. Under adequate lighting, inspect the inside of the diverter switch oil compartment for mechanical or electrical damage (creepage paths, signs of discharge). 3. Document any defects with a camera. 4. After the inspection, cover diverter switch oil compartment with the on- load tap-changer head cover. If you are unsure, please contact the MR Technical Service department for advice. In such cases photographs of the affected areas are helpful. 8.2 Cleaning and inspecting diverter switch insert 1. NOTICE! Thoroughly clean diverter switch insert using only new trans- former oil. Other cleaning agents may cause damage to the on-load tap- changer and transformer. 2. Perform thorough visual inspection of the diverter switch insert. 3. Under adequate lighting, inspect diverter switch insert for mechanical or electrical damage (creepage paths, signs of discharge). Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 31  8 Maintaining on-load tap-changer 8.3 Inspecting coupling tube The coupling tube has to be removed from the diverter switch insert for the check. 1. Remove the 6 screws holding the lower screening ring. Figure 25: Screws on the lower screening ring 2. Lift the lower screening ring and remove the 6 spacing sleeves using pli- ers. Figure 26: Spacing sleeves on the lower screening ring 3. Pull off the coupling tube. 4. Clean the coupling tube with transformer oil. Note the oil quality limit val- ues. 32 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 8 Maintaining on-load tap-changer 5. Perform thorough visual inspection of the inside and outside of the cou- pling tube. Check for mechanical or electrical damage (leakage paths, discharge marks). The coupling tube is refitted following the instructions for removal but in re- verse order. When refitting, ensure alignment of the red adjustment mark (at top of cou- pling tube) and the adjustment mark on the diverter switch insert (energy ac- cumulator, see appendix [► 66]). Figure 27: Adjustment marks In order to ensure that the adjustment marks are positioned correctly, when assembling the coupling tube, the parts must be positioned as they were be- fore being disassembled. 8.4 Checking transition resistors Check the transition resistors visually for unusual appearances. Figure 28: Transition resistors Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 33  8 Maintaining on-load tap-changer 8.5 Replacing vacuum interrupters Replace the vacuum interrupters, including pre-fitted supporting structure, after 600,000 tap change operations. Please contact MR Technical Service. 8.6 Checking insulating shim Before refitting the diverter switch insert in the oil compartment, ensure that all six insulating shims are in the energy accumulator carrier. Figure 29: Insulating shims 8.7 Replacing varistor connection leads The two varistor connection leads and their fasteners should be replaced af- ter 600,000 tap change operations. Please contact MR Technical Service. 8.8 Replacing diverter switch insert Replace the complete diverter switch insert after 1.2 million switching opera- tions. Please contact MR Technical Service. 8.9 Replacing fixed main contacts Replace the fixed main contacts (MC) in full after 1.2 million tap change op- erations. Please contact MR Technical Service. 8.10 Maintaining tap selector The tap selector must be maintained after 1.2 million tap change operations. Please contact MR Technical Service. 34 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 8 Maintaining on-load tap-changer 8.11 Cleaning and inspecting protective relay RS Proceed as follows to clean and inspect the protective relay: 1. Loosen screws on cover and take off cover. Figure 30: Cover with hexagon socket screws Figure 31: Cover with hexagonal head screws 2. Clean protective relay with a brush and new insulating oil. 3. Use spring balance to measure retaining force of flap valve. The retain- ing force must be between 2.0...2.2 N. Contact the Technical Service at Maschinenfabrik Reinhausen GmbH if the above value is not observed. Figure 32: Flap valve Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 35  8 Maintaining on-load tap-changer 4. Visually inspect dry-reed magnetic switches. Ensure that dry-reed mag- netic switches are intact and sealed. 5. Replace seal in cover. 6. Fit cover and screw down. Figure 33: Cover with hexagon socket screws Figure 34: Cover with hexagonal head screws 36 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 9 Inserting diverter switch insert 9 Inserting diverter switch insert Proceed as follows to insert the diverter switch insert: NOTICE Damage to the on-load tap-changer and transformer! Damage to the on-load tap-changer and transformer from used fixtures and gaskets! ► Only use lock tabs, lock disks, lock nuts and the on-load tap-changer head cover o-ring once and replace once removed. ► Only use self-locking screws with thread coating with micro-encapsulat- ed adhesives once and replace once removed. Note expiry date of new parts. ► Ensure that screw connection points and elements are free of oil and grease. 9.1 Inserting diverter switch insert 1. To fit the diverter switch insert, ensure that the tap selector coupling is in the adjustment position. Figure 35: Adjustment marks in oil compartment base VACUTAP® VRC/VRE Figure 36: Adjustment marks in oil compartment base VACUTAP® VRDVRF Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 37  9 Inserting diverter switch insert Figure 37: Adjustment marks in oil compartment base VACUTAP® VRG 2. Ensure that the diverter switch insert's energy accumulator is inter- locked (the energy accumulator's eccentric disk is at its dead center, see "Adjustment plan" for tap-changer variant used in the appendix). 3. Attach lifting gear to diverter switch insert and position diverter switch in- sert over oil compartment. NOTICE Damage to the on-load tap-changer and transformer! Damage to on-load tap-changer and transformer due to diverter switch in- serts being confused in K applications (on-load tap-changer set comprising a VACUTAP® VR I and VACUTAP® VR II). ► When using the diverter switch insert, note the red markings on the coupling flange and on the on-load tap-changer head: VACUTAP® VR I: 1 marking VACUTAP® VR II: 2 markings 4. Align diverter switch insert such that the red markings at the top of the coupling flange and on the on-load tap-changer head are opposite one another. 38 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 9 Inserting diverter switch insert 5. Slowly lower diverter switch insert until it hits the oil compartment base. Figure 38: Aligning diverter switch insert 6. Carefully press until energy accumulator carrier is in position. The shape of the tap selector coupling ensures that coupling with the oil compart- ment base is only possible in the correct position. 7. Check the distance between the upper edge of the diverter switch insert coupling tube and the head flange. The distance is 10 ± 2 mm (cover mounting and bell-type tank mounting). Figure 39: Distance between the upper edge of the coupling tube and head flange 9.2 Inserting oil suction pipe NOTICE Damage to the on-load tap-changer! Damage to the on-load tap-changer and oil suction pipe due to incorrect or- der of installation. ► Strictly adhere to the order of installation. Make sure to always install the diverter switch insert before inserting the oil suction pipe into the oil compartment. Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 39  9 Inserting diverter switch insert 1. Insert the oil suction pipe into the on-load tap-changer head. Figure 40: Inserting oil suction pipe 2. Fasten oil suction pipe on retaining bracket with cable tie. Figure 41: Fastening the oil suction pipe 40 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 9 Inserting diverter switch insert 9.3 Inserting tap-change supervisory control (if present) 1. Insert tap-change supervisory control with mounting plate and drive shaft. Figure 42: Mounting plate with drive shaft 2. Check that drive shaft feather key is seated correctly in groove. Figure 43: Feather key and groove Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 41  9 Inserting diverter switch insert 3. Secure mounting plate (3 or 4 nuts and locking washers depending on model). Figure 44: Mounting plate 4. Connect plug connector outside its bracket. Figure 45: Plug connector 5. Insert plug connector into the bracket. Figure 46: Plug connector in bracket 42 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 9 Inserting diverter switch insert 6. Attach Teflon strip with nut onto stud bolts. Figure 47: Stud bolt with Teflon strip and nut 9.4 Inserting the tap position indicator without multiple coarse change-over selector Due to the coupling pin, the tap position indicator disc can only be installed when in the correct position. ► Place tap position indicator disk on indicator drive shaft, slide spring clip on to shaft end. Figure 48: Tap position indicator disk Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 43  9 Inserting diverter switch insert 9.5 Inserting tap position indicator with multiple coarse change-over selector with more than 35 operating posi- tions 1. Place panel with bracket on indicator drive shaft and secure with hexa- gon screws and associated lock tab. Figure 49: Panel 2. Insert position-indication disk horizontally between panel and bracket and fit cover disk. Align tap position indicator disc and cover disk to pro- duce a continuous red line. Figure 50: Position-indication disk 44 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 9 Inserting diverter switch insert 3. Secure cover disk with countersunk head screw. The countersunk head screw must be suitable for center-punching. Figure 51: Cover disk 4. Secure countersunk head screw by center-punching. 9.6 Filling oil and securing on-load tap-changer head cover 1. NOTICE! Fill diverter switch oil compartment with insulating oil to upper edge of coupling shaft. Ensure that dielectric strength and water content of insulating oil comply with the limit values provided in the appendix [► 60]. Otherwise damage to the on-load tap-changer and transform- er may result. 2. NOTICE! Insert new o-ring in on-load tap-changer head cover. Take care not to damage the o-ring. A damaged o-ring will cause oil to es- cape from the diverter switch oil compartment, resulting in on-load tap- changer damage. Also ensure that the sealing surfaces are clean. 3. Place the on-load tap-changer head cover on the on-load tap-changer head. Ensure that the red triangular marks on the on-load tap-changer head and the on-load tap-changer head cover match up. Figure 52: On-load tap-changer head cover Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 45  9 Inserting diverter switch insert 4. Screw down on-load tap-changer head cover with on-load tap-changer head. Figure 53: On-load tap-changer head cover 5. Open stop-cock between protective relay and oil conservator. 6. Fill oil conservator with insulating oil. 7. Vent on-load tap-changer head on air-vent valve E1 of on-load tap- changer head cover. To do this, remove screw cap and lift valve tappet with a screwdriver. Figure 54: Screw cap Figure 55: Valve tappet 8. Seal air-vent valve E1 with screw cap (tightening torque 10 Nm). 46 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 9 Inserting diverter switch insert 9. Vent pipe connection S on on-load tap-changer head. To do this, open pipe connection's screw cap and vent screw. Close screw cap again af- ter venting. Figure 56: Pipe connection S 10. Take oil sample from diverter switch oil compartment. 11. Record temperature of oil sample just after sample is taken. 12. Determine dielectric strength and water content at a diverter switch oil temperature of 20 °C ± 5 °C. The dielectric strength and water content must comply with the limit values provided in the appendix [► 60]. 9.7 Installing horizontal drive shaft 1. Secure horizontal drive shaft between upper gear unit and bevel gear with coupling brackets and 4 or 6 screws. Refer to the drive shaft oper- ating instructions for details. Figure 57: Securing drive shaft Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 47  9 Inserting diverter switch insert 2. Use hose clips to secure guard plate to horizontal drive shaft. Figure 58: Securing guard plate 3. For special design types featuring cardan shafts, be sure to check the expansion bellows and the lubricant reservoir of the cardan shafts. You will find a detailed description of how to fit the drive shaft in the MR op- erating instructions "Drive shaft". 9.8 Coupling on-load tap-changer and motor-drive unit WARNING Danger of death or severe injury! Danger of death or severe injury due to motor-drive unit starting up by acci- dent and due to electric voltage! ► Before starting any coupling work make sure that the motor protective switch is tripped. ► Carry out any adjustment work in manual mode only. ► When manually operating the motor-drive unit only use the hand crank provided for this purpose. ► Note that the hand crank safety switch causes a 2-pole disconnection of the motor circuit but that the control circuit is not interrupted. 48 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 9 Inserting diverter switch insert NOTICE Damage to the on-load tap-changer! Performing too many operations without complete oil filling will damage the on-load tap-changer! ► Do not perform more than 250 tap-change operations on the on-load tap-changer without oil before drying. ► Before first actuating the on-load tap-changer after drying the trans- former, the tap selector and change-over selector (if present) must be completely immersed in transformer oil and the oil compartment must be completely filled with oil. 1. NOTICE! Move on-load tap-changer/off-circuit tap-changer and the mo- tor-drive unit into adjustment position before commencing any adjust- ment work. Ensure that tap position indicators for the motor-drive unit and on-load tap-changer/off-circuit tap-changer match. Otherwise dam- age to the on-load tap-changer and transformer may result. Figure 59: Adjustment position Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 49  9 Inserting diverter switch insert 2. Attach the hand crank in the motor-drive unit to the shaft end located in the upper cover plate. This activates a hand crank safety switch which disconnects the motor circuit at 2 poles. Figure 60: Hand crank 3. Turn the hand crank clockwise until the diverter switch operation begins. When turning the hand crank, observe the tap-change indicator which mechanically reflects the progress of the tap-change operation. One on-load tap-change operation is represented by one rotation of the tap- change indicator. This indicator is divided into 33 tap-change indicator sec- tions each of which corresponds to one hand crank revolution in the stand- ard motor-drive unit design. The time of the switchover depends on the on- load tap-changer/off-circuit tap-changer type, but is always 2 tap-change in- dicator sections before the tap-change indicator gray field at the latest. Figure 61: Turning the hand crank until the diverter switch operation begins 50 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 9 Inserting diverter switch insert 4. Once the diverter switch operation begins, turn the hand crank in the same direction while counting the sections required for the pointer to reach the mid-position of the area marked in gray on the tap-change in- dicator. Note the determined value A and the direction of rotation (exam- ple: A=2). Figure 62: Counting the tap changes needed to reach the mid-position 5. If the determined value A is less than 8 tap-change indicator sections, turn another 8-A tap-change indicator sections in the same direction (ex- ample: 8-2=6) to complete the tap-change operation. Then turn in the opposite direction until the pointer is in the mid-position of the area marked in gray on the tap-change indicator. Figure 63: Completing diverter switch operation 6. Turn the hand crank counter-clockwise until the diverter switch opera- tion begins Figure 64: Turning hand crank in the opposite direction 7. Once the diverter switch operation begins, turn the hand crank in the same direction while counting the sections required for the pointer to reach the mid-position of the area marked in gray on the tap-change in- Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 51  9 Inserting diverter switch insert dicator. Note the determined value B and the direction of rotation (exam- ple: B=5). If the values obtained for A and B are identical, the on-load tap-changer and the motor-drive unit are correctly coupled. The number of tap-change indicator sections from the beginning of the diverter switch operation until the pointer reaches the mid-position of the area marked in gray on the tap-change indicator should be the same in both directions. A slight asymmetry of a maximum of 1 tap-change indicator sec- tion is permissible. Figure 65: Counting tap-change indicator sections needed to reach the mid-position 8. If the determined value B is less than 8 tap-change indicator sections, turn another 8-B tap-change indicator sections in the same direction (ex- ample: 8-5=3) to complete the tap-change operation. Then turn in the opposite direction until the pointer is in the mid-position of the area marked in gray on the tap-change indicator. Figure 66: Completing diverter switch operation 9. If the values determined for A and B are different, establish correction value C by halving the difference between A and B: C=|(A-B) x 0.5| Example: C=|(2-5) x 0.5|=|-1.5|=1.5 Also take numbers after the decimal point into account. 10. If the correction value |C| is less than 0.5 tap-change indicator section, no further actions are required. Refer to point 17 for how to proceed next. 52 VACUTAP® VR II III (with VR I 2602) 2343793/01 EN Maschinenfabrik Reinhausen 2013 9 Inserting diverter switch insert 11. Use hand crank to perform one on-load tap-changing operation up to the diverter switch action in the direction with the higher determined val- ue A or B (example: counter-clockwise because B > A). 12. Uncouple the motor-drive unit and the vertical drive shaft by removing the coupling brackets. After uncoupling, don't turn drive shaft any fur- ther. Figure 67: Uncoupling motor-drive unit and drive shaft 13. Operate the motor-drive unit using the hand crank in same direction, continuing by C tap-change indicator sections on the tap-change indica- tor (example: 1.5 tap-change indicator sections). 14. Couple motor-drive unit and on-load tap-changer by refitting the vertical drive shaft (reverse order to that described under point 12, tightening torque 9 Nm). Do not turn drive shaft and motor-drive unit any further. DANGER Danger of death or severe injury and damage to property! Danger of death and damage to property due to incomplete on-load tap- changing operation! ► Always complete on-load tap-changing operation by continuing to turn hand crank in the same direction until mid-position of area marked in gray on the tap-change indicator is reached. ► If the on-load tap-changer is coupled correctly, the on-load tap-chang- ing operation is always completed by continuing to turn hand crank in the same direction until the mid-position is reached. There is no need to calculate a correction value as in points 5 and 8. Maschinenfabrik Reinhausen 2013 2343793/01 EN VACUTAP® VR II III (with VR I 2602) 53  9 Inserting diverter switch insert 15. Continue to turn in the same direction while counting the sections re- quired for the pointer to reach the mid-position of the area marked in gray on the tap-change indicator. Note the determined value A and the direction of rotation. If the determined value B is less than 8 tap-change indicator sections, turn another 8-