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On-load tap-changer, type UC with 

motor-drive mechanisms, type BUE/BUL

Repair guide

1ZSE 5492-129 en, Rev. 6

Summary of Contents for UC Series

Page 1: ...On load tap changer type UC with motor drive mechanisms type BUE BUL Repair guide 1ZSE 5492 129 en Rev 6...

Page 2: ...This document must not be copied without our written permission and the contents thereof must not be imparted to a third party nor be used for any unauthorized purpose Contravention will be prosecuted...

Page 3: ...E provides additional information to assist in carrying out the work de scribed Safety precautions WARNING Before any work is carried out on the on load tap changer Make sure that the trans former is...

Page 4: ...ressure relay trip follow the instructions in the chapter Pressure relay in this guide During oil handling WARNING Unused transformer oil is slightly harmful Fumes from unused warm oil may irritate th...

Page 5: ...housing Take care to avoid ingestion of moist air when oil is drained If the ambient air is moist let incoming air pass through a dehydrating breather with slow air flow to obtain proper dehy dration...

Page 6: ......

Page 7: ...Procedure__________________________________________________23 3 2 Replacement of diverter switch housing cover gasket_ ________________27 3 2 1 General_________________________________________________...

Page 8: ......

Page 9: ...tap changers type UC are housed in the transformer tank The motor drive mechanisms types BUE or BUL are attached to the transformer tank and connected to the on load tap changer by means of drive sha...

Page 10: ...contacts Intermediate gear Insulating shaft Bevel gear Position indicator Fig 1 General arrangement of on load tap changer type UC Earthing terminal Serial No Diverter switch housing Serial No Connect...

Page 11: ...f the transformer is manufactured by ABB in Ludvika Sweden NOTE One of these serial numbers must be quoted in all correspondence and telefax messages and during any telephone conversations with ABB Fa...

Page 12: ...propriate Maintenance guide You will need the Maintenance guide since references are made to it 1 6 Tightening torque The following tightening torques are recommended for metallic screw joints M6 10 N...

Page 13: ...indicate a leakage between the diverter switch housing and the transformer tank Make sure that the cause for the alarm is not over filling at commissioning or overhaul This can be checked by adjustin...

Page 14: ...r condition Fault finding procedure The pressure relay has tripped during normal operation 1 Examine the diverter switch according to section 3 5 Examination of the diverter switch after a pres sure r...

Page 15: ...ctive motor switch 6 If the motor drive has been handcranked against the mechanical endstop handcrank back to end position The on load tap changer performs more steps than ordered or operates to wards...

Page 16: ...reaches the position indica tor 2 Measure the resistance on the terminals of the position transmitter in all positions after both raise and lower operations WARNING Before starting any work inside the...

Page 17: ...incoming supply WARNING Dangerous voltage 2 3 3 Miscellaneous Error condition Fault finding procedure Corrosion and or condensa tion in the motor drive mecha nism cabinet 1 Check the function of the...

Page 18: ...ed when the on load tap changer has through positions Closed when the on load tap changer is in through positions fm_00236 Fig 4 Standard circuit diagram BUE For actual information use the circuit dia...

Page 19: ...19 1ZSE 5492 129 en Rev 6 fm_00237 Fig 5 Contact timing diagram BUE 2 Trouble shooting...

Page 20: ...ed when the on load tap changer has through positions Closed when the on load tap changer is in through positions fm_00238 Fig 6 Standard circuit diagram BUL For actual information use the circuit dia...

Page 21: ...21 1ZSE 5492 129 en Rev 6 Fig 7 Contact timing diagram BUL fm_00239 2 Trouble shooting...

Page 22: ...cautious CAUTION When making this repair it is important that neither the on load tap changer nor the motor drive mechanism is operated with the shafts disconnected 3 1 2 Tools required Normal set of...

Page 23: ...a signed certificate from the engineer in charge The oil in the diverter switch housing may be hot Be cautious Clamps washers and screws TC_00151 Fig 8c Tap changer from above Position indicator Bolts...

Page 24: ...are in the same service position as the motor drive If something is out of range please consult ABB for advisory CAUTION To take an on load tap changer that is not aligned and or out of position into...

Page 25: ...he fixed brass coupling to the gear box closest to the motor drive Put on the protection tubes and hose clamps 18 Fit the loosened coupling to the replaced gear box Tighten the two screws closest to t...

Page 26: ...all gear boxes are lubricated with grease If not apply grease on the gears 24 Make a final check that all gear boxes are in their exact positions within the tolerance given in Fig 8 and that all on lo...

Page 27: ...rter switch housing No open fire hot surfaces or sparks may be present during opening of the housing or draining from the valve After the cover is removed let the gas vent away approxi mately 15 min b...

Page 28: ...load tap changer for connection dimensions of the oil valve 3 3 3 Procedure WARNING The oil in the diverter switch housing may be hot Be cautious There is always a cushion of explosive gases in the t...

Page 29: ...the pump 12 The level in the oil conservator and the gas cushion are now restored CAUTION Avoid to do the restoring in damp weather since moisture will get into the diverter switch housing If the res...

Page 30: ...e screws to new ones length 20 and 10 or 35 mm 3 Turn the contact arm on the new multi position switch to the same position as the exist ing multi position switches Place the transparent cover on the...

Page 31: ...djustments Distance screw L 20 mm Distance screw L 10 mm or 35 mm Multi position switch Transparent cover Shaft Upper coupling half Bottom place Sliding bearing Torque disc Lower coupling half Contact...

Page 32: ...e relay trip Follow the procedure in section Lifting and cleaning the diverter switch in the Mainte nance guide when lifting the diverter switch Look for flash marks loose parts etc Measure the transi...

Page 33: ...reconnect the incoming wires If the pressure relay does not withstand the electrical stress the pressure relay should be replaced see section 3 9 Replacement of pressure relay 2 Function test Set the...

Page 34: ...acement of pressure relay 1 Set the three way valve handle to the test position see Fig 11 and the information plate on the pressure relay WARNING Disconnect all power sources before any work is carri...

Page 35: ...35 1ZSE 5492 129 en Rev 6 3 Repairs and adjustments Fig 11 Pressure relay Information plate Valve handle Test tap R 1 8 TC_00264 Three way valve handle Quick coupling Pressure relay Connection nut...

Page 36: ...nents SE 771 80 Ludvika Sweden Phone 46 240 78 20 00 Fax 46 240 121 57 E Mail sales se abb com www abb com electricalcomponents Contact us Copyright 2011 ABB All rights reserved 1ZSE 5492 129 en Rev 6...

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