Questions and Answers
What is the maximum torque allowed when reattaching the support cylinder with support plate?
What component must be operated several times to check its mechanical function after reattachment?
What should be ensured during the alignment of the reattached support plate and accumulator housing?
During the installation of the diverter switch unit, how should it be lowered into the oil compartment?
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What type of oil should be used to fill the tap changer oil compartment?
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What is the appropriate maximum torque for the bleeder screw during oil filling?
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When filling the tap changer oil compartment, what is essential to do with the oil filter unit according to the instructions?
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What aspect is crucial when setting the insulating drive shaft during installation?
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What must be done after reinstalling all contact shells in relation to the diverter switch?
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What tool is needed to actuate the eccentric of the energy accumulator?
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When detaching the support cylinder, how many screws must be undone?
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What should be used to clean the support cylinder and the insulating drive shaft?
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What is the first step when working with a diverter switch unit that includes a support cylinder?
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How is the diverter switch set to its mid-position?
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What precaution should be taken when removing screws from the support cylinder?
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If replacement work is necessary on the diverter switch unit, which section refers to this procedure?
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What is the correct torque for securing the bolts of a special design bell-type tank?
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Which procedure should be followed before energizing the transformer?
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How should the oil be filled in the diverter switch compartment?
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What is necessary to ensure when replacing the tap changer head cover?
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What is the function of the bleeder valve in the tap changer head?
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What tool is required to lift the valve tappet in the bleeder valve?
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What is a critical step when installing the position indicating disc?
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What type of fasteners is used to secure the components of the tap changer assembly?
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What is the purpose of counting the sections from the tap change operation?
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What must be done if there is a difference in section counts when adjusting the motor drive?
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Which of the following is necessary before coupling the tap changer and motor drive?
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What is described as 'minor asymmetry' in the operation of the diverter switch?
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How should the adjustment process begin when the tap changer is in position 10?
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What indicates that the motor drive and tap changer are properly adjusted?
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What action should follow the counting of sections towards the diverter switch?
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What is the ultimate goal of ensuring symmetrical coupling between the motor drive and tap changer?
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What is the function of the locking bar mentioned in the content?
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What should be avoided during the raising of the device according to the content?
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Which column tube is identified in the content as 250mm?
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What is suggested about the travelling crab during operation?
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Which of the following is a potential risk during the operation of the device?
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The column tubes referenced in the content are available in what lengths?
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What should be ensured regarding the travelling crab during the operation?
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In relation to safety, what is the main precaution advised?
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The indication wheel for the tap change operation is divided into sections where each section corresponds to two rotations of the crank.
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The diverter switch's action is set to begin at the red center mark on the indication wheel.
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One tap change operation of the diverter switch equates to one complete revolution of the drive mechanism.
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The tap changers are adjusted using a crank and an indication wheel that features a red center mark for reference.
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The operational note specifies that tap changes should occur at intervals after reaching the motor drive's maximum position.
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The diverter switch operation indicates that multiple tap change operations can be executed in one full rotation of the indication wheel.
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It is essential to check for misalignment between the tap changer and motor drive unit.
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The maximum torque for securing the tap changer is stated to be 8 Nm.
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Trial operations should be performed only across a limited range of tapping.
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If the protective relay operates, it is safe to reset it immediately.
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The operational tests of the motor drive and tap changer can be skipped if the system appears functional.
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Screwing and locking the coupling is a final step in the adjustment process.
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The diverter switch does not need to be withdrawn if the protective relay operates.
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The follow-up of the motor drive must be the same in both forward and reverse directions.
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The spring energy accumulator must be switched to an unlocked position after reinstalling all contact shells.
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When detaching the support cylinder, it is necessary to undo 8 screws M10 x 20 each with a self-locking nut.
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The insulating drive shaft should be cleaned with a brush and sandpaper before reinstallation.
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The eccentrics of the energy accumulator are operated using an operating key to ensure the pawl locks-in.
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Transition resistors are checked for function after the diverter switch unit has been reinstalled.
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After cleaning, the support cylinder and insulating drive shaft should be left wet with transformer oil.
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The diverter switch unit is ready to be reinstalled after performing all procedures in sections 5.1 to 5.5.
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It is essential to operate the diverter switch only once to verify its mechanical function.
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To secure the support cylinder with support plate, 8 bolts M8 x 20 with a maximum torque of 25 Nm are required.
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The insulating drive shaft must be aligned such that the shaft key points away from the eccentric.
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The oil filling process must involve the use of only new mineral insulating oil for the tap changer oil compartment.
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Mechanical function checks of the diverter switch should be performed after reattaching the insulating drive shaft.
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The correct process for reinstalling the diverter switch unit involves lowering it gently into the oil compartment.
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During the installation of the diverter switch unit, the tap changer oil conservator can be filled with any type of oil.
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It is necessary to vent the suction pipe before filling the tap changer oil compartment.
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The transition resistors check must be conducted after operating the diverter switch several times.
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The travelling crab must be locked for operating safety during the raising of the device.
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It is permissible to raise the device with the travelling crab locked under certain conditions.
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The operation of the device is safe when the travelling crab is engaged.
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Operating safety is compromised if the travelling crab is not monitored while the device is raised.
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Raising the device without precautions related to the travelling crab poses a minimal risk.
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During the safe operation of the device, the travelling crab can be left unattended.
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Study Notes
Reinstallation Process of Diverter Switch Unit
- Spring energy accumulator must be set from mid-position to switched position and locked-in post reinstallation of contact shells.
- Use a screwdriver to insert between wind-up and cocking sledge of the energy accumulator to actuate the eccentric.
- Ensure the pawl locks-in to confirm correct setup.
- Check the diverter switch mechanical function by operating it multiple times.
- Verify transition resistors per specified section before setting the diverter switch to the withdrawal position.
Diverter Switch Unit with Support Cylinder
- Procedures detailed in sections 5.1 and 5.2 must be followed when working with units having a support cylinder.
- Detach the support cylinder after removing eight M8 x 20 screws with self-locking nuts.
- Prevent loss of parts into the diverter switch during disassembly.
- Clean the support cylinder and insulating drive shaft with a brush and transformer oil; flush and dry thereafter.
- Set the diverter switch to mid-position using the operating key handle in the eccentric drive shaft groove.
Final Assembly Steps
- Lock the spring energy accumulator using the operating key after following procedures from sections 5.3 to 5.8.
- Reattach the cleaned support cylinder with the support plate using eight bolts M8 x 20, ensuring alignment of triangle marks for proper installation.
- Operate the diverter switch multiple times to check functionality before setting it back to withdrawal position.
Reinstallation of Diverter Switch Unit
- Remove the tap changer head cover to lower the diverter switch unit into the oil compartment carefully.
- Fill the oil conservator with new mineral insulating oil maintaining the original oil level.
- Securely attach the diverter switch unit with screws to the support plate, replacing the O-ring if necessary.
- Open the stop valve between the protective relay and oil conservator and vent the tap changer head through the bleeder valve.
Adjustment Process
- Ensure symmetric coupling during adjustment by verifying position indication readings of both motor drive and tap changer.
- Adjust the motor drive if discrepancies are noted between counts of sections in either direction during the operation.
- Follow outlined procedures for coupling and uncoupling for precise adjustment of tap changer and motor drive.
Safety Precautions
- New oil fills must not occur unless the transformer is de-energized for a specified time.
- Engage the travelling crab safely during operation, preventing locking during critical moments to ensure operational safety.
Spring Energy Accumulator Setup
- Reinstall all contact shells before adjusting the spring energy accumulator.
- Set the accumulator from the mid-position to a switched position of the diverter switch and lock it in.
- Use a screwdriver to position the wind-up sledge and cocking sledge for the energy accumulator.
- Operate the eccentric with an operating key until the pawl locks in place.
- Test the mechanical function of the diverter switch multiple times.
- Recheck transition resistors as outlined in section 5.2.
- Reset the diverter switch to its withdrawal position (refer to section 5.1).
Diverter Switch Unit with Support Cylinder
- Follow procedures from sections 5.1 and 5.2 for a diverter switch unit that includes a support cylinder.
- Detach the support cylinder by removing 8 M8 x 20 screws with self-locking nuts.
- Avoid dropping parts into the diverter switch during disassembly.
- Clean both inside and outside of the support cylinder with a brush and transformer oil, then flush and dry.
- Clean the insulating drive shaft thoroughly.
- Use the operating key to set the diverter switch to its mid-position, aligning it with the eccentric drive shaft.
Reinstallation Steps for Diverter Switch Unit
- Reattach the support cylinder and support plate using 8 bolts, ensuring alignment marks on the housing.
- Torque bolts to a maximum of 22 Nm.
- Operate the diverter switch multiple times to confirm mechanical functionality.
- Check transition resistors again as mentioned in section 5.2.
- Set the diverter switch to the withdrawal position per section 5.1 again.
Oil Filling Procedure
- Vent the suction pipe by loosening the screw cap of the assembly.
- Fill the oil compartment only with new mineral insulating oil, ensuring it adheres to IEC 296 guidelines.
- Start the oil filter unit and bleed as necessary before remounting the diverter switch unit.
Operational Testing
- With the transformer in the OFF position, ensure circuit breakers cannot close.
- Verify the alignment of position indicators for both the tap changer and the motor drive unit.
- Lock the tap changer head cover with 8 screws, setting a maximum torque of 5 Nm.
- Assess alignment between the tap changer and motor drive; misalignment can cause severe damage.
- Confirm symmetrical coupling of the motor drive with the tap changer and adjust if necessary.
Final Checks Prior to Power
- Conduct trial operations across the full tapping range to ensure functionality.
- Confirm the action timing of the diverter switch is set correctly, ensuring synchronization with motor drive action.
- The tap change indication wheel must reflect proper intervals during operation for efficient transitioning.
Important Safety Notes
- During device raising, ensure the traveling crab is not locked for operational safety.
- Address any malfunction indicated by the protective relay before resetting.
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Description
This quiz covers the procedural steps for setting up the spring energy accumulator after reinstalling contact shells. It includes detailed instructions on the locking mechanisms of the diverter switch and checking mechanical functions, using the appropriate tools. Understanding these steps is crucial for ensuring proper functionality in electrical systems.
