Motor Drive Unit Safety Procedures
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Questions and Answers

What is the maximum rated through-current of a three-phase VACUTAP® VRF OLTC as indicated in the type identification?

  • 1200 A
  • 1000 A
  • 1300 A (correct)
  • 1100 A

    • In the context of VACUTAP® VR, how many operating positions does the tap selector system have, including the mid-position?

  • 19 (correct)
  • 17
  • 23
  • 21

    • Which of the following components is used specifically as a coarse tap selector in the VACUTAP® VR operations?

  • Three-phase selector
  • Change-over selector (correct)
  • Mid-position selector
  • Fine tap selector

    • What type diagram is associated with the three-phase VACUTAP® VRF OLTC as mentioned in the documentation?

    <p>10 19 1G</p> Signup and view all the answers

    What is the pitch of the tap selector contact circle for the three-phase VACUTAP® VRF OLTC?

    <p>10</p> Signup and view all the answers

    What action should be taken to prevent damage to the OLTC when using the motor drive unit?

    <p>Ensure that the OLTC and motor drive unit are coupled.</p> Signup and view all the answers

    What should be noted before removing the diverter switch insert?

    <p>The current operating position of the OLTC.</p> Signup and view all the answers

    What is the primary safety precaution to take before carrying out maintenance work on OLTCs?

    <p>Ensure the transformer is switched off and secured against restarting.</p> Signup and view all the answers

    What is the risk associated with switching oil in the OLTC?

    <p>It is flammable and poses a fire hazard.</p> Signup and view all the answers

    What should be performed before opening the head cover on the OLTC?

    <p>Lower the oil level in the oil compartment.</p> Signup and view all the answers

    Which auxiliary equipment is necessary for servicing OLTCs, according to the preparation instructions?

    <p>Clean empty barrels and transformer oil.</p> Signup and view all the answers

    Which component must be actuated to block the motor drive unit against electrical operation?

    <p>The motor protective switch.</p> Signup and view all the answers

    What should be done with the transformer terminals before maintenance on OLTCs?

    <p>Connect them to the ground and short-circuit them.</p> Signup and view all the answers

    What is the maximum weight mentioned for the diverter switch insert during maintenance?

    <p>50 kg.</p> Signup and view all the answers

    What is the primary purpose of the tap position indicator?

    <p>Indicate the adjustment position.</p> Signup and view all the answers

    In what condition is it safe to operate the motor drive unit?

    <p>Only when the OLTC and motor drive unit are coupled.</p> Signup and view all the answers

    What type of damage may potentially occur if proper precautions are not taken during OLTC maintenance?

    <p>Permanent damage to the OLTC and transformer.</p> Signup and view all the answers

    What is essential to view before performing maintenance on the motor drive unit?

    <p>Documentation of the current OLTC position.</p> Signup and view all the answers

    Which item is NOT listed as necessary tools for OLTC maintenance?

    <p>Hydraulic press.</p> Signup and view all the answers

    What is indicated as a risk of electric shock during OLTC maintenance?

    <p>Failing to switch off the transformer.</p> Signup and view all the answers

    What type of rags are recommended for cleaning during OLTC maintenance?

    <p>Lint-free cleaning rags.</p> Signup and view all the answers

    Which step needs to be performed before removing the coupling tube from the diverter switch insert?

    <p>Remove the 6 screws</p> Signup and view all the answers

    What is the maximum tightening torque for the screws when removing the coupling tube?

    <p>30 Nm</p> Signup and view all the answers

    What should be checked for during the visual inspection of the coupling tube?

    <p>Mechanical or electrical damage</p> Signup and view all the answers

    What must be ensured regarding the coupling tube upon reassembly?

    <p>The top hole matches the adjustment marker</p> Signup and view all the answers

    What is advised regarding the diverter switch insert during tap change operations?

    <p>Do not operate the diverter switch insert while removed</p> Signup and view all the answers

    Which of the following is NOT a step in checking the coupling tube?

    <p>Tightening the screws to maximum torque</p> Signup and view all the answers

    What might indicate a significant problem with the coupling tube?

    <p>Mechanical or electrical damage</p> Signup and view all the answers

    Why should any damaged parts be replaced immediately?

    <p>To prevent further damage to the OLTC and transformer</p> Signup and view all the answers

    What is the recommended service interval for the tap selector maintenance?

    <p>After 1.2 million tap change operations</p> Signup and view all the answers

    Which component is to be replaced after 1.2 million tap change operations?

    <p>Fixed main contacts (MC)</p> Signup and view all the answers

    Who should be contacted for technical service regarding maintenance?

    <p>MR Technical Service</p> Signup and view all the answers

    In what order should the diverter switch insert be reinstalled?

    <p>In reverse order of disassembly</p> Signup and view all the answers

    What is the purpose of a varistor in electrical systems?

    <p>To protect against voltage surges</p> Signup and view all the answers

    What is the significance of the information provided in figures 24 to 34?

    <p>They illustrate the installation process for a component.</p> Signup and view all the answers

    Where is the MR Technical Service located?

    <p>Regensburg, Germany</p> Signup and view all the answers

    What does the complete diverter switch require after 1.2 million tap change operations?

    <p>Replacement</p> Signup and view all the answers

    It is safe to perform tap change operations of the diverter switch without the head cover in place.

    <p>False</p> Signup and view all the answers

    Removing the head cover requires loosening 20 screws with locking washers.

    <p>False</p> Signup and view all the answers

    It is essential to ensure that no small parts are dropped into the diverter switch oil compartment during maintenance.

    <p>True</p> Signup and view all the answers

    The round rubber gasket is not required to prevent damage during disassembly.

    <p>False</p> Signup and view all the answers

    Care must be taken to prevent the OLTC from blocking during the removal of the diverter switch insert.

    <p>True</p> Signup and view all the answers

    The head cover can be removed without any specific tool requirements.

    <p>False</p> Signup and view all the answers

    The diverter switch insert must be removed after moving the OLTC into a special adjustment position.

    <p>True</p> Signup and view all the answers

    The installation of the head cover should use mismatched screws to ensure a tight fit.

    <p>False</p> Signup and view all the answers

    OLTCs must be serviced after 300,000 tap change operations.

    <p>True</p> Signup and view all the answers

    The insulating oils in the transformer can be monitored by anyone, without any specific qualifications.

    <p>False</p> Signup and view all the answers

    Functional tests of the protective relay should be performed according to Operating Instructions No. 59.

    <p>True</p> Signup and view all the answers

    Regular inspections of the OLTC head, the protective relay, and the motor drive unit are discouraged.

    <p>False</p> Signup and view all the answers

    Proper function of the in-built electric heater in the protective housing is a maintenance priority.

    <p>True</p> Signup and view all the answers

    The state of the dehydrating breather for the OLTC should be monitored as part of regular maintenance.

    <p>True</p> Signup and view all the answers

    Maintenance reports do not need to be forwarded if the service is conducted by trained personnel.

    <p>False</p> Signup and view all the answers

    Gaskets of the protective housing do not require inspection during maintenance.

    <p>False</p> Signup and view all the answers

    The diverter switch insert can be safely operated while removed from the system.

    <p>False</p> Signup and view all the answers

    The coupling tube needs to be cleaned with transformer oil to maintain its integrity.

    <p>True</p> Signup and view all the answers

    Mechanical or electrical damage can be identified by conducting a visual inspection of the coupling tube.

    <p>True</p> Signup and view all the answers

    The 6 screws removed during the coupling tube check should be tightened to a torque of 50 Nm.

    <p>False</p> Signup and view all the answers

    The position of the hole at the top of the coupling tube is not critical during reassembly.

    <p>False</p> Signup and view all the answers

    Reassembly of the coupling tube can be done in any order after removal.

    <p>False</p> Signup and view all the answers

    Checking the coupling tube is only necessary for three-phase OLTCs.

    <p>False</p> Signup and view all the answers

    Spacer sleeves are not involved in the maintenance of the coupling tube.

    <p>False</p> Signup and view all the answers

    The automatic switch-off function of the OLTC should only be tested in one end position.

    <p>False</p> Signup and view all the answers

    Operating Instructions No. 42 details the procedure for installing the drive shaft.

    <p>True</p> Signup and view all the answers

    The transformer can be switched on immediately after completing the required checks.

    <p>False</p> Signup and view all the answers

    The bleeding procedure involves connections detailed in Operating Instructions No. 138.

    <p>True</p> Signup and view all the answers

    A careful visual inspection of the coupling tube is deemed unnecessary during OLTC maintenance.

    <p>False</p> Signup and view all the answers

    Before applying voltage, some test operations must be conducted to check the mechanical functions of the tap changer.

    <p>True</p> Signup and view all the answers

    Section 8 is dedicated to further checks that need to be performed before operating the OLTC.

    <p>True</p> Signup and view all the answers

    The operation of the OLTC can be carried out without adhering to the cautionary notes provided.

    <p>False</p> Signup and view all the answers

    Pressing the 'ON' button on the protective relay while in the danger zone of the transformer is safe.

    <p>False</p> Signup and view all the answers

    The protective relay must be reset by pressing the 'OFF' button after conducting an active protection test.

    <p>False</p> Signup and view all the answers

    The circuit breaker should remain closed during the passive protection test of the transformer.

    <p>False</p> Signup and view all the answers

    After a protective relay is triggered, the diverter switch insert must be inspected as per maintenance instructions.

    <p>True</p> Signup and view all the answers

    The OLTC and transformer are not at risk of damage if the instructions are followed correctly during maintenance.

    <p>True</p> Signup and view all the answers

    Leaving the danger zone of the transformer is unnecessary after pressing the 'OFF' button on the protective relay.

    <p>False</p> Signup and view all the answers

    The circuit breaker of the transformer must remain open after resetting the protective relay.

    <p>True</p> Signup and view all the answers

    In the event of major faults, contacting the transformer manufacturer is optional.

    <p>False</p> Signup and view all the answers

    What does the warning signal word 'CAUTION' indicate?

    <p>The situation could result in minor or moderate injury.</p> Signup and view all the answers

    Which pictogram represents a warning of combustible substances?

    <p>Warning of combustible substances.</p> Signup and view all the answers

    What kind of information is mainly provided to simplify procedures?

    <p>Important information for improving understanding.</p> Signup and view all the answers

    Which statement represents a critical point in the maintenance procedure for OLTCs?

    <p>Read and understand the technical file before maintenance.</p> Signup and view all the answers

    Which of the following indicates that a hazardous situation could lead to death or serious injury?

    <p>WARNING</p> Signup and view all the answers

    What is the primary purpose of using signal words in notices?

    <p>To indicate the severity of a hazard.</p> Signup and view all the answers

    What kind of hazard does the pictogram indicating dangerous electrical voltage warn against?

    <p>Risk of electric shock.</p> Signup and view all the answers

    Which statement about the general safety information is false?

    <p>It should be ignored by experienced technicians.</p> Signup and view all the answers

    What could potentially block the diverter switch insert during maintenance?

    <p>Parts within the diverter switch oil compartment</p> Signup and view all the answers

    What is essential to ensure when removing the tap position indicator from a multiple coarse change-over selector?

    <p>The red marks align properly</p> Signup and view all the answers

    Which component must be handled carefully to avoid damaging the tap position indicator during removal?

    <p>Shaft end</p> Signup and view all the answers

    What is necessary to perform after removing the hexagon screws during the removal of the diverter switch insert?

    <p>Remove the associated lock tab</p> Signup and view all the answers

    What should be checked in preparation for removing the diverter switch insert?

    <p>The number of parts before disassembly</p> Signup and view all the answers

    What might indicate a potential problem during the disassembly of the diverter switch insert?

    <p>Excessive force when pulling the panel and bracket</p> Signup and view all the answers

    Which tool is necessary for leveraging off the cover disk when accessing the position-indication disk?

    <p>Flat screwdriver</p> Signup and view all the answers

    What ensures that the product does not present hazards throughout its entire life cycle?

    <p>Compliance with legislation and operational quality assurance system</p> Signup and view all the answers

    What must be ensured regarding the diverter switch oil compartment before starting maintenance work?

    <p>No parts are missing from disassembly</p> Signup and view all the answers

    Which of the following represents inappropriate use of the product?

    <p>Using the equipment with a different transformer than specified</p> Signup and view all the answers

    What must be done to avoid liability for damage related to the product?

    <p>Consult before making any changes to the product</p> Signup and view all the answers

    Which aspect is a strict requirement for the product's operational safety?

    <p>Maintenance according to this technical file guidelines</p> Signup and view all the answers

    What is deemed inappropriate regarding product operation?

    <p>Altering the product specifications without consultation</p> Signup and view all the answers

    Which of the following statements reflects the importance of using specified equipment?

    <p>It ensures optimal product quality and safety</p> Signup and view all the answers

    What is a key consideration regarding changes to the product?

    <p>Consultation is vital before implementing unauthorized changes</p> Signup and view all the answers

    What is primarily ensured by maintaining compliance with the specified requirements?

    <p>Consistent high-quality operational standards</p> Signup and view all the answers

    What should be ensured for safe operation regarding the hand crank used for manual operation of the motor-drive unit?

    <p>Only the hand crank provided for this purpose should be used.</p> Signup and view all the answers

    What is a crucial step to prevent damage to the on-load tap-changer when performing operations?

    <p>Perform less than 250 tap-change operations without oil.</p> Signup and view all the answers

    Which precaution must be taken before starting any coupling work on the motor-drive unit?

    <p>Ensure the motor protective switch is tripped.</p> Signup and view all the answers

    What must be done before actuating the on-load tap-changer after drying the transformer?

    <p>Completely immerse the tap selector and change-over selector in oil.</p> Signup and view all the answers

    What is an essential condition to fulfill when inserting a diverter switch insert?

    <p>The OLTC should be disconnected from the main power supply.</p> Signup and view all the answers

    In what scenario might the control circuit still be active even when the hand crank safety switch is engaged?

    <p>If the hand crank is used intermittently.</p> Signup and view all the answers

    What should be verified regarding the cardan shafts during maintenance of special design types?

    <p>The condition of expansion bellows and the lubricant reservoir.</p> Signup and view all the answers

    What is the outcome of performing too many operations on the on-load tap-changer without complete oil filling?

    <p>Damage to the on-load tap-changer.</p> Signup and view all the answers

    What is the importance of continuing to turn the hand crank until the mid-position is reached during on-load tap-changing operations?

    <p>It ensures a complete tap-changing operation.</p> Signup and view all the answers

    What is the required tightening torque for refitting the vertical drive shaft of the motor-drive unit?

    <p>9 Nm</p> Signup and view all the answers

    When operating the motor-drive unit using the hand crank, which direction should the crank be turned?

    <p>In the same direction as the tap-change indicator.</p> Signup and view all the answers

    What happens if the on-load tap-changer is not coupled correctly during operation?

    <p>The operation may result in incomplete tap-changing.</p> Signup and view all the answers

    What action is specifically NOT required when determining the sectors needed for tap-changing operations?

    <p>Calculating a correction value.</p> Signup and view all the answers

    During the on-load tap-changing operation, what must be done after noting the determined value A?

    <p>Continue to turn the crank until the necessary sections are reached.</p> Signup and view all the answers

    What safety precaution is emphasized regarding the hand crank during operation?

    <p>Do not turn the motor-drive unit or drive shaft further than needed.</p> Signup and view all the answers

    What is a critical danger if the on-load tap-changing operation is incomplete?

    <p>Risk of death or severe injury.</p> Signup and view all the answers

    It is mandatory to visibly connect all transformer terminals to ground and short circuit them before performing maintenance.

    <p>True</p> Signup and view all the answers

    An energized transformer poses no risk of injury during maintenance as long as the maintenance team is careful.

    <p>False</p> Signup and view all the answers

    Before maintenance, the transformer needs to be switched off and locked to prevent unintentional restart.

    <p>True</p> Signup and view all the answers

    Regular cleaning rags are suitable for use during the oil change of an on-load tap-changer.

    <p>False</p> Signup and view all the answers

    The oil quantity for cleaning and oil change is the same regardless of the on-load tap-changer type and its rated voltage Um.

    <p>False</p> Signup and view all the answers

    The oil level in the on-load tap-changer rises automatically when the drain valve is opened.

    <p>False</p> Signup and view all the answers

    It is safe to operate electric devices during maintenance work on the on-load tap-changer.

    <p>False</p> Signup and view all the answers

    The on-load tap-changer head can be opened without first de-energizing the tap-change supervisory control.

    <p>False</p> Signup and view all the answers

    The sealing surfaces on the on-load tap-changer head cover must be in sound condition before removing it.

    <p>True</p> Signup and view all the answers

    Ten liters of oil should be drained from the on-load tap-changer before sealing the air-vent valve E1.

    <p>True</p> Signup and view all the answers

    Head cover removal of the on-load tap-changer requires the loosening of specifically five screws.

    <p>False</p> Signup and view all the answers

    All auxiliary circuits must be energized before opening the head cover of the on-load tap-changer.

    <p>False</p> Signup and view all the answers

    Removal of the diverter switch insert must be done without concern for additional parts falling into the oil compartment.

    <p>False</p> Signup and view all the answers

    The VACUTAP® VR II III series requires maintenance after 500,000 tap change operations.

    <p>False</p> Signup and view all the answers

    The dielectric strength of diverter switch oil is assessed only after maintenance procedures.

    <p>False</p> Signup and view all the answers

    The head cover of the OLTC can be removed without any tools.

    <p>False</p> Signup and view all the answers

    During the maintenance of an OLTC, the insulating oils can be checked by unqualified personnel.

    <p>False</p> Signup and view all the answers

    Removing the diverter switch insert requires moving the OLTC into a specific adjustment position.

    <p>True</p> Signup and view all the answers

    The protective relay must be functionally tested according to Operating Instructions No. 56.

    <p>False</p> Signup and view all the answers

    Mismatched screws should be used for the installation of the head cover in the OLTC.

    <p>False</p> Signup and view all the answers

    Regular inspections of the OLTC head, protective relay, and motor drive unit are encouraged.

    <p>True</p> Signup and view all the answers

    Cleaning and inspecting the diverter switch insert is a step included in the maintenance of the OLTC.

    <p>True</p> Signup and view all the answers

    The oil level in the diverter switch oil compartment should be raised before removing components.

    <p>False</p> Signup and view all the answers

    Replacing vacuum interrupters is not listed as a task during OLTC maintenance.

    <p>False</p> Signup and view all the answers

    The tap-change supervisory control is optional and not always present in the OLTC.

    <p>True</p> Signup and view all the answers

    Dielectric strength and water content limits for on-load tap-changer oil can be found in the appendix.

    <p>True</p> Signup and view all the answers

    The primary purpose of a safety precaution is to ensure the safe removal of the OLTC electric motors.

    <p>False</p> Signup and view all the answers

    The hand crank should be turned in the opposite direction of the tap-change indicator during operation.

    <p>False</p> Signup and view all the answers

    A correction value must be calculated for every on-load tap-changing operation.

    <p>False</p> Signup and view all the answers

    The mid-position on the tap-change indicator is identified by a gray area.

    <p>True</p> Signup and view all the answers

    If the determined value during operation is less than 8 tap-change indicator sections, no further action is required.

    <p>False</p> Signup and view all the answers

    The tightening torque for the vertical drive shaft should be 15 Nm during assembly.

    <p>False</p> Signup and view all the answers

    Turning the hand crank past the mid-position can lead to severe damage or injury.

    <p>True</p> Signup and view all the answers

    Each section on the tap-change indicator represents 1.0 tap-change indicator sections.

    <p>False</p> Signup and view all the answers

    The motor-drive unit can be coupled to the on-load tap-changer in any alignment.

    <p>False</p> Signup and view all the answers

    The silver coating on the contacts inside the diverter switch oil compartment must be discolored for proper function.

    <p>False</p> Signup and view all the answers

    New transformer oil should be used to clean the diverter switch insert.

    <p>True</p> Signup and view all the answers

    Mechanical or electrical damage should be investigated only under dim lighting conditions.

    <p>False</p> Signup and view all the answers

    Phantom images can be documented with a camera to indicate defects in the oil compartment.

    <p>False</p> Signup and view all the answers

    The coupling tube does not need to be removed for inspection of the diverter switch insert.

    <p>False</p> Signup and view all the answers

    Six screws hold the lower screening ring of the coupling tube in place.

    <p>True</p> Signup and view all the answers

    The diverter switch oil compartment can be uncovered once a year for inspection.

    <p>False</p> Signup and view all the answers

    Spacing sleeves are not required for the maintenance of the coupling tube.

    <p>False</p> Signup and view all the answers

    What is the first step before removing the on-load tap-changer head cover?

    <p>De-energize all auxiliary circuits</p> Signup and view all the answers

    What must be done to lower the oil level in the diverter switch oil compartment?

    <p>Lift the valve tappet on the air-vent valve E1</p> Signup and view all the answers

    Which tool is suggested to actuate the valve tappet on the air-vent valve E1?

    <p>A screwdriver</p> Signup and view all the answers

    What is advised to avoid losing during the removal of the horizontal drive shaft?

    <p>The coupling bolts</p> Signup and view all the answers

    In what situation should the coupling brackets be loosened?

    <p>Before removing the drive shaft</p> Signup and view all the answers

    What is the significance of closing the stop-cock between the oil conservator and on-load tap-changer?

    <p>To isolate the oil compartment before draining</p> Signup and view all the answers

    What procedure should be followed after lifting the valve tappet on the air-vent valve E1?

    <p>Open the drain valve</p> Signup and view all the answers

    What is the primary requirement for personnel conducting maintenance on the on-load tap-changer?

    <p>They should be MR-trained or suitably qualified.</p> Signup and view all the answers

    What should be done after loosening the screws on the coupling brackets?

    <p>Remove the drive shaft</p> Signup and view all the answers

    What document should be forwarded to update maintenance files after performing maintenance by unapproved personnel?

    <p>A detailed report of the maintenance performed.</p> Signup and view all the answers

    Why is it necessary to check the dielectric strength of diverter switch oil after maintenance?

    <p>To ensure compliance with limit values for safety and functionality.</p> Signup and view all the answers

    What should be done with the dielectric strength measurements of the diverter switch oil?

    <p>They must comply with the limit values provided in the appendix.</p> Signup and view all the answers

    What is the maximum time recommended for maintenance of an on-load tap-changer pole when well prepared?

    <p>One day per pole.</p> Signup and view all the answers

    What specific information must be included in inquiries about spare parts?

    <p>The serial number and number of tap-change operations.</p> Signup and view all the answers

    How should maintenance intervals be determined?

    <p>According to the maintenance schedule provided in the appendix.</p> Signup and view all the answers

    What is a crucial factor for ensuring efficient maintenance of the on-load tap-changer?

    <p>Preparation and organization of the maintenance process.</p> Signup and view all the answers

    What is the structure of single-step instructions in the technical file?

    <p>Aim of action, Step 1, Result of step, Result of action</p> Signup and view all the answers

    Which pictogram indicates a warning of dangerous electrical voltage?

    <p>Warning of dangerous electrical voltage</p> Signup and view all the answers

    What is a required step before the maintenance of OLTCs?

    <p>Familiarize with the technical file</p> Signup and view all the answers

    What should be included in multi-step instructions according to the technical file structure?

    <p>Requirements, Several Steps, Final Result</p> Signup and view all the answers

    Which type of warnings are indicated by pictograms in the technical file?

    <p>Warnings of danger points and electrical hazards</p> Signup and view all the answers

    What type of information is crucial in the instruction system of the technical file?

    <p>Detailed procedure instructions</p> Signup and view all the answers

    Which additional component is often considered non-essential during maintenance of OLTCs?

    <p>Familial inspection of all used tools</p> Signup and view all the answers

    What should be avoided during the removal of the diverter switch insert?

    <p>Dropping small parts into the compartment</p> Signup and view all the answers

    What is the recommended action for replacing fixed main contacts for models other than VR I 1601/1801 after a specified number of operations?

    <p>Replace after 1.2 million operations</p> Signup and view all the answers

    What must be inspected visually in the maintenance of the protective relay?

    <p>The dry-reed magnetic switches</p> Signup and view all the answers

    How often should the tap selector be maintained according to the provided guidelines?

    <p>Every 1.2 million operations</p> Signup and view all the answers

    What is the required retaining force of the flap valve during inspection?

    <p>2.0 N to 2.2 N</p> Signup and view all the answers

    For models VR I 1601/1801, after how many tap change operations should the fixed main contacts be fully replaced?

    <p>300,000 operations</p> Signup and view all the answers

    What should be done to the protective relay before replacing the seal in the cover?

    <p>Loosen screws and take off the cover</p> Signup and view all the answers

    What is the purpose of replacing the fixed main contacts after specified operations?

    <p>To ensure operational reliability</p> Signup and view all the answers

    What tool is recommended for cleaning the protective relay?

    <p>Brush and new insulating oil</p> Signup and view all the answers

    What is crucial to ensure when filling the diverter switch oil compartment with insulating oil?

    <p>Insulating oil must be filled to the upper edge of the coupling shaft.</p> Signup and view all the answers

    What procedure must be followed regarding the o-ring when installing the on-load tap-changer head cover?

    <p>The o-ring must be new and should not be damaged during installation.</p> Signup and view all the answers

    Which steps should be ensured when securing the cover disk with a countersunk head screw?

    <p>To center-punch the screw to ensure it is secured.</p> Signup and view all the answers

    What alignment is necessary when placing the head cover on the on-load tap-changer?

    <p>Matching the red triangular marks on both components.</p> Signup and view all the answers

    What should be checked regarding the sealing surfaces before inserting a new o-ring?

    <p>Surfaces must be clean to prevent damage to the o-ring.</p> Signup and view all the answers

    Which of the following is a potential consequence of a damaged o-ring in the diverter switch?

    <p>Oil leakage from the diverter switch oil compartment.</p> Signup and view all the answers

    What type of screw is specified for securing the cover disk?

    <p>Countersunk head screws suitable for center-punching.</p> Signup and view all the answers

    What might happen if improper insulating oil is used in the diverter switch?

    <p>It might lead to damage to the on-load tap-changer and transformer.</p> Signup and view all the answers

    Qualified personnel can usually perform maintenance on an on-load tap-changer pole within two days.

    <p>False</p> Signup and view all the answers

    The dielectric strength of diverter switch oil must comply with set limit values during both operation and after maintenance.

    <p>True</p> Signup and view all the answers

    Reports on maintenance performed should be sent to ensure updates to maintenance files.

    <p>True</p> Signup and view all the answers

    The dielectric strength of the diverter switch oil does not need to be checked after maintenance.

    <p>False</p> Signup and view all the answers

    All maintenance should be conducted by the Technical Service department to ensure safety and compliance.

    <p>False</p> Signup and view all the answers

    A fax template for reporting maintenance is provided in the appendix for convenience.

    <p>True</p> Signup and view all the answers

    The limit values for dielectric strength and water content are only applicable during maintenance periods.

    <p>False</p> Signup and view all the answers

    Maintenance of the on-load tap-changer can be completed irrespective of the serial number provided.

    <p>False</p> Signup and view all the answers

    The on-load tap-changer can have a maximum of 35 operating positions with a change-over selector.

    <p>True</p> Signup and view all the answers

    The type designation of an on-load tap-changer does not provide any information on the maximum rated through current.

    <p>False</p> Signup and view all the answers

    Inspection of the OLTC head and motor drive unit is considered unnecessary by default.

    <p>False</p> Signup and view all the answers

    The pitch of the tap selector is indicated in the type designation for the VACUTAP® VRF.

    <p>True</p> Signup and view all the answers

    The diverter switch insert must be left in place during maintenance to avoid damage.

    <p>False</p> Signup and view all the answers

    The highest voltage for equipment Um in the type designation is measured in volts.

    <p>False</p> Signup and view all the answers

    OLTCs should undergo service every 300,000 tap change operations.

    <p>False</p> Signup and view all the answers

    The tap position indicator is used to determine the maximum operating position of an OLTC.

    <p>False</p> Signup and view all the answers

    The VACUTAP® VRD/VRF has a selector size identified as E/F.

    <p>False</p> Signup and view all the answers

    The adjustment plan for VACUTAP® VRC with multiple coarse change-over selector is designed for change-over selector division 10.

    <p>True</p> Signup and view all the answers

    Technical service for maintenance of OLTCs is generally recommended to be performed by personnel without specific qualifications.

    <p>False</p> Signup and view all the answers

    The diverter switch oil's dielectric strength and DC resistance measurement are part of the maintenance scope.

    <p>True</p> Signup and view all the answers

    The VACUTAP® VRF adjustment plan allows for both change-over and coarse tap selector connections.

    <p>True</p> Signup and view all the answers

    Operating the motor-drive unit is safe even if the horizontal drive shaft has been removed.

    <p>False</p> Signup and view all the answers

    A specific adjustment plan exists for the VACUTAP® VRG that utilizes a reversing change-over selector connection.

    <p>False</p> Signup and view all the answers

    The adjustment plan without change-over selector for the VACUTAP® VRF is designated as model number 10016148.

    <p>True</p> Signup and view all the answers

    It is necessary to ensure that no ignition sources are present when working with the on-load tap-changer due to explosive gases.

    <p>True</p> Signup and view all the answers

    The number 2343791 refers to a different version of VACUTAP® than the one labeled 2343791/02 EN.

    <p>False</p> Signup and view all the answers

    Conductive and grounded hoses that are approved for flammable liquids must not be used during maintenance.

    <p>False</p> Signup and view all the answers

    The head cover of the on-load tap-changer requires no specific tools for removal.

    <p>False</p> Signup and view all the answers

    Vacutap® VRC is described as having coarse tap connections with specific divisions.

    <p>True</p> Signup and view all the answers

    Damage to the on-load tap-changer can occur if the motor-drive unit is operated while not coupled.

    <p>True</p> Signup and view all the answers

    Adjustment plans for VACUTAP® VR are outlined only for the RC/RD series.

    <p>False</p> Signup and view all the answers

    VACUTAP® VRC, adjustment plan for division 12, provides four coarse tap connections.

    <p>False</p> Signup and view all the answers

    Regular inspections of the OLTC head, protective relay, and the motor drive unit are encouraged.

    <p>False</p> Signup and view all the answers

    The instruction document contains detailed information about the performance of the tap selector system.

    <p>True</p> Signup and view all the answers

    The diverter switch insert must be removed after the on-load tap-changer is placed into a normal operating position.

    <p>False</p> Signup and view all the answers

    Explosive gases may be present under the on-load tap-changer head cover.

    <p>True</p> Signup and view all the answers

    The maximum measured current for a filled oil compartment during a DC resistance measurement is 50 A DC regardless of whether the current is interrupted.

    <p>True</p> Signup and view all the answers

    DC resistance measurements on transformer windings can exceed 10% of their rated current if the winding is not overheating.

    <p>False</p> Signup and view all the answers

    It is permissible to measure DC resistance with a maximum of 10 A DC in an empty oil compartment without interrupting the measured current.

    <p>False</p> Signup and view all the answers

    When the measured current is interrupted before changing the operating position, the maximum allowed current remains the same as when it is uninterrupted.

    <p>False</p> Signup and view all the answers

    Performing maintenance on an energized transformer can lead to severe injury or even death.

    <p>True</p> Signup and view all the answers

    The maximum current for measuring DC resistance should always be kept at 50 A DC for safety reasons in any scenario.

    <p>False</p> Signup and view all the answers

    The risk of electric shock during OLTC maintenance is eliminated by ensuring the transformer is de-energized.

    <p>True</p> Signup and view all the answers

    DC resistance measurements should not be conducted while the transformer is under load.

    <p>True</p> Signup and view all the answers

    Study Notes

    Preparation for OLTC Maintenance

    • Ensure safety by switching off the transformer and securing against reactivation.
    • Connect all transformer terminals to ground and short-circuit them to prevent electric shock.
    • Required auxiliary equipment includes clean barrels, transformer oil, an oil pump, absorbent cleaning rags, a workbench, an oil sump, and lifting devices.
    • Maximum weight of the diverter switch insert is 50 kg; withdrawal height depends on OLTC type and rated voltage.
    • Use appropriate tools and fixtures as specified in technical documentation.

    General Information on OLTCs

    • On-load tap-changers (OLTCs) are categorized with unique type identifications for different versions.
    • Example: VACUTAP® VRF OLTC has a max rated current of 1300 A and voltage rating up to 72.5 kV.
    • Tap selector size and operating positions must be noted; mid-position is one of the operating positions.

    Operations and Maintenance

    • Never operate the motor drive unit while uncoupled from the OLTC.
    • Maintain the adjustment position before removing the diverter switch insert.
    • Lower oil level in the oil compartment prior to opening the head cover due to flammable liquid risks.
    • Inspect and clean the coupling tube and ensure it is free of mechanical or electrical damage.
    • Reassemble parts ensuring correct positioning according to adjustment markers.

    Maintenance Procedures

    • Diverter switch inserts must be replaced after 1.2 million tap change operations.
    • Fixed main contacts also require replacement following the same tap change operation threshold.

    Technical Service Contact

    • For maintenance queries or parts replacements, contact MR Technical Service (Maschinenfabrik Reinhausen GmbH):

    Installation Guidelines

    • Reinstall the diverter switch insert by reversing the removal steps, following detailed figures in technical documentation to ensure correct assembly.

    OLTC Maintenance and Inspections

    • Occasional visual inspections of the OLTC head, protective relay, and motor drive unit are essential for early damage detection.
    • Regular servicing of OLTCs is crucial to maintain high operational reliability.
    • Key inspection areas include oil tightness at sealing locations, gaskets of the protective housing, and the state of the dehydrating breather.
    • Functional tests of the protective relay should be performed according to Operating Instructions No. 59.
    • Insulating oils must be monitored to ensure their quality and proper function.

    Maintenance Intervals and Protocol

    • OLTCs require servicing after 300,000 tap change operations; the motor drive unit has an operation counter.
    • Personnel performing maintenance should be trained or qualified by MR to ensure compliance and safety.
    • Maintenance reports must be forwarded for documentation and record-keeping.

    Safety Precautions

    • Avoid tap change operations without the head cover to prevent damage to the diverter switch.
    • Ensure all screws and small parts are accounted for during disassembly and reinstallation to avoid blockages and operational hazards.

    Removing and Inspecting Components

    • Head cover removal requires careful handling of 24 screws (M10/w.s.17); avoid damaging faying surfaces.
    • Check and clean the coupling tube, inspecting for leaks or discharge tracking.
    • Reinstallation must align the coupling tube's position with the adjustment marker.

    Functional Testing and Further Checks

    • Perform mechanical function checks before voltage application to the transformer, making sure to run the tap changer through the entire operating range.
    • Check protective relay functionality by conducting both passive and active protection tests.

    Technical Support and Further Assistance

    • Contact MR Technical Service for any major issues or if the protective relay triggers, providing them with pertinent details for further support.

    Signal Words in Warning Notices

    • WARNING: Indicates hazardous situations that could lead to death or serious injury if not avoided.
    • CAUTION: Indicates situations that may result in minor or moderate injury if not addressed.
    • NOTICE: Indicates necessary measures to prevent property damage.

    Pictograms for Dangers

    • Danger Point: Warns of a danger point.
    • Electrical Voltage: Alerts to the presence of dangerous electrical voltage.
    • Combustible Substances: Indicates the risk of combustible materials.
    • Tipping Risk: Warns of danger related to tipping hazards.

    Safety Information

    • The technical file contains detailed maintenance procedures to ensure safe product use.
    • Appropriate Use: Adheres to legislation and health/safety standards throughout the product's lifecycle—from delivery to disposal.
    • Product maintenance must follow specified technical guidelines, using appropriate tools and equipment.

    Inappropriate Use

    • Use beyond prescribed guidelines is deemed inappropriate; manufacturers do not accept liability for such misuse.
    • Unauthorized modifications can lead to personal injury or property damage.

    Removal and Maintenance Guidelines

    • Removal of the tap position indicator requires specific steps such as removing the spring clip and countersunk head screws.
    • Care must be taken to keep track of parts to ensure proper reassembly.

    Inserting Diverter Switch Insert

    • During coupling work, ensure the motor protective switch is off to prevent accidental start-up.
    • Manual operation should be conducted with the designated hand crank only.

    Operational Warnings

    • WARNING: Incomplete operations could lead to severe injury or property damage, emphasizing the need to complete all tasks before concluding the tap-changing process.
    • NOTICE: Limit tap-change operations without oil to prevent damage to the on-load tap-changer; ensure complete oil filling before first activation post-drying.

    General Operations

    • Continuation of turning during the tap-changing operation is critical for correct functionality.
    • Identification of directional rotation is necessary for proper operation and safety.

    Introduction to Maintenance Manual

    • Maintenance manual for VACUTAP® VR II III on-load tap-changer, covering safe and proper maintenance procedures.
    • Important notes on validity, completeness, and potential changes in product information.
    • Supporting documents and notation conventions detailed for clarity.

    Safety Considerations

    • General safety practices emphasized to prevent death or severe injury during maintenance.
    • Mandatory safety precautions include switching off, locking, grounding, and ensuring de-energization of transformers.
    • Outline of necessary auxiliary equipment such as oil pumps, cleaning tools, and containers for oil changes.

    Operational Surveillance

    • Monitoring during operation to ensure safe functioning and early identification of potential issues.

    Product Overview

    • Functionality and setup of on-load tap-changer are described, highlighting various models and type designations.

    Maintenance Protocols

    • Detailed scope of maintenance includes intervals for dielectric strength checks and DC resistance measurements.
    • Specific measures for assessing dielectric strength of diverter switch oil, both during operation and after maintenance.

    Preparation for Maintenance

    • Essential safety precautions and equipment needed prior to servicing.
    • Steps for adjusting the on-load tap-changer and ensuring readiness for maintenance tasks.

    Diverter Switch Insert Removal

    • Comprehensive steps for removing the diverter switch insert, including precautions around energized systems and explosive gases.
    • Importance of checking sealing surfaces and o-rings during maintenance to avoid contamination.

    Maintenance Procedures

    • Cleaning and inspecting the diverter switch oil compartment and ensuring proper functioning of switch components.
    • Specific procedures for replacement parts including vacuum interrupters, varistor connection leads, and main contacts.

    Reassembly Process

    • Protocols for correctly re-inserting diverter switch components and ensuring oil levels are adequate.
    • Guidelines for securing and testing the operational readiness via trial tap-change operations and setting mechanical stops.

    Commissioning the Transformer

    • Procedures for commissioning the transformer post-maintenance to ensure all systems are operational and safe.

    Additional Information

    • Maintenance schedules and limit values for dielectric strength and water content of tap-changer oil provided in the appendix.
    • Detailed tap-change processes, switching sequences, and adjustment plans for specific VACUTAP® models, catering to different configuration needs.### Checking Diverter Switch Oil Compartment
    • Inspect fixed oil compartment contacts and the interior of the diverter switch oil compartment using a mirror and lamp.
    • Ensure the silver coating on the contacts remains undamaged and not discolored.
    • Conduct thorough inspections for mechanical or electrical damage, such as creapage paths or discharge signs, under good lighting.
    • Use a camera to document any defects found during inspection.
    • After inspections, cover the diverter switch oil compartment with the on-load tap-changer head cover.
    • For uncertainties, contact MR Technical Service; providing photographs of defects can be beneficial.

    Cleaning and Inspecting Diverter Switch Insert

    • Use only new transformer oil for cleaning the diverter switch insert to avoid damage.
    • Perform a detailed visual inspection of the diverter switch insert.
    • Under adequate lighting, check for any mechanical or electrical damage.

    Inspecting Coupling Tube

    • Remove the coupling tube from the diverter switch insert for inspection.
    • Detach the lower screening ring by removing six screws securing it.
    • Extract the six spacing sleeves with pliers once the lower screening ring is lifted.
    • Carefully pull off the coupling tube and clean it with transformer oil.
    • Operate the motor-drive unit using the hand crank in the same direction to reach specific tap-change indicator sections.
    • Reattach the vertical drive shaft to connect the motor-drive unit and on-load tap-changer, ensuring a tight torque of 9 Nm.

    Safety Precautions for On-load Tap-changer Operation

    • Complete any on-load tap-changing operation to avoid potential dangers, such as incomplete processes that can lead to severe injury or property damage.
    • Always continue turning the hand crank in the same direction until reaching the mid-position on the tap-change indicator column.
    • Ensure the coupling is correct to facilitate safe operation without needing to calculate correction values.

    Pictograms and Warning Notices

    • Pictograms are used to communicate specific dangers.
    • Key warning pictograms include:
      • Danger point warning
      • Dangerous electrical voltage warning
      • Combustible substances warning
      • Tipping hazard warning

    Information and Instruction Systems

    • Information presentation simplifies understanding of procedures.
    • Contains both single-step and multi-step instructions:
      • Single-step instructions follow a simple structure of aim, requirements, action steps, and results.
      • Multi-step instructions involve a sequence of steps with individual results noted for each action.

    Safety and Maintenance Protocols

    • General safety guidelines provide comprehensive product maintenance instructions.
    • Thoroughly read the technical file to ensure proper product usage.
    • Maintenance should be performed by qualified personnel and can often be done within one day per on-load tap-changer pole.
    • Maintenance reports need to be forwarded to maintain regulatory compliance and updates.

    Oil Management and Testing

    • Dielectric strength tests are crucial during and after maintenance to ensure safety:
      • Check oil dielectric strength in the diverter switch oil compartment.
      • The oil level must be lowered before opening the on-load tap-changer head cover.
    • Procedures are in place for handling oil levels and screw caps to prevent contamination or damage.

    Maintenance Intervals and Requirements

    • Fixed main contacts must be replaced after a specific number of tap change operations:
      • 1.2 million operations for most types.
      • 300,000 operations specifically for VR I 1601/1801 models.
    • Maintenance of the tap selector is required after 1.2 million operations.

    Conducting Electrical and Mechanical Inspections

    • Protective relay inspection involves cleaning, measuring retaining forces, and visual checks of magnetic switches.
    • Special attention to the positioning of components and seals during reassembly to prevent leaks.

    Finalizing Maintenance Procedure

    • Proper filling of the diverter switch oil compartment is critical:
      • Insulating oil must meet dielectric strength and water content specifications.
      • A new o-ring must be installed correctly to prevent oil leaks.
    • Ensuring proper alignment of the on-load tap-changer head cover during installation is essential for operational integrity.

    VACUTAP® Overview

    • VACUTAP® on-load tap-changer models include various selector sizes and adjustment plans for specific applications.
    • Available models include VRF, VRC I/VRE I, VRD, and VRG, each with specific configurations and selector connection types, such as coarse and change-over selectors.

    Configuration and Design

    • On-load tap-changer is divided into components: head, diverter switch oil compartment, and tap selector.
    • Standard models operate without a change-over selector, offering a maximum of 18 positions, while models with a change-over selector can accommodate up to 35 positions.
    • Type designation includes model abbreviations, phase count, current ratings, voltage levels, tap selector size, and operational settings.

    Maintenance Guidelines

    • Maintenance should ideally be performed by trained personnel or the manufacturer's Technical Service to ensure efficiency and safety.
    • Maintenance procedures can often be completed in one day if adequately organized.
    • Required maintenance tasks include checking dielectric strength of diverter switch oil and monitoring DC resistance of transformer windings.

    Safety Precautions

    • Strict safety measures are vital due to the risk of electric shock and explosion.
    • Precautions include ensuring no ignition sources and de-energizing circuits before maintenance begins.

    Measurement Considerations

    • DC resistance measurements require restricting current to prevent overheating, with set maximums based on the oil compartment's status and the method used.
    • Measurements should account for operational position changes and the timing of current interruptions.

    Preparatory Steps for Maintenance

    • Record current position and change to adjustment position as per connection diagrams.
    • Implement safety protocols to mitigate risks associated with energized components.

    Diverter Switch Insert Removal

    • Removal of the diverter switch insert must follow strict safety and procedural guidelines to avoid damage or personal injury.
    • Precautions include blocking the motor-drive unit to prevent unauthorized operation during maintenance.

    Important Maintenance Components

    • Serious danger exists with explosive gases in maintenance areas, necessitating a no-ignition environment.
    • Conductivity and grounding of hoses and pumps must be ensured when working with flammable substances.

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    Related Documents

    Maintenance Instructions WA 290/02 PDF
    VACUTAP® VR II III Maintenance Manual PDF
    VACUTAP® VR I On-Load Tap-Changer Maintenance Manual PDF

    Description

    This quiz focuses on the critical safety procedures and auxiliary equipment related to the Motor Drive Unit as outlined in document WA 290/02 - VACUTAP® VR. Test your knowledge on the key practices and equipment necessary for safe operation. Ideal for professionals working in electrical engineering and maintenance.

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