Material And Spare Parts Required; Procedure; Changing The End Stops In Motor-Drive Mechanism; General - ABB UZE Repair Manual

3.3.3 Material and spare parts required

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3.3.4 Procedure

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2.
The cover for access to conductors on top of UZF tank may be opened only after
draining the transformer main tank.
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3.4 Changing the end stops in motor-drive mechanism

3.4.1 General

This instruction explains how to reduce the regulating range of the on-load tap-changer.
The motor-drive mechanism original end stop screws (lower end stop and upper end stop,
see Fig. 9) must not be moved.

3.4.2 Tools required

Key for socket head cap screw (width across flats 4 mm)
1ZSE 5492-128 en, Rev. 4
Maintenance Guide
Clean and empty drums
Rags (not cotton waste)
Gasket for front cover (UZE/UZF) and/or top cover (UZF)
Grease as for ball-bearings
Tighten the domed nuts (19 mm). Tightening torque max 42 Nm. If the oil leakage still
remains, the gasket has to be replaced.
Replacement of front cover gasket: Drain the on-load tap-changer. For information
about oil draining, see the Maintenance Guide.
Replacement of top cover gasket: Lower the oil level in the transformer according to the
transformer documentation.
Loosen the nuts and remove the front cover/top cover. When removing the top cover,
take care of the washer with earthing snag placed on one of the stud bolts.
Clean the gasket surfaces. Replace the gasket with a new one.
The gasket is not glued. The gasket surface against the cover is coated with grease to
facilitate openings in the future. Use grease as for ball-bearings.
Mount the front cover/top cover and fasten the domed nuts. Tightening torque 42 Nm.
When the top cover is mounted, one of the stud bolts should have a washer with earth-
ing snags against the cover in order to ensure potential connection of the top cover.
Restore the oil level. For information about oil filling, and correct oil level. See the Main-
tenance Guide or the transformer documentation.
WARNING
CAUTION
3 Repairs and adjustments
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