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On-load tap-changers type UBB

The UBB is a selector switch type of on-load tap-changer. It is designed for mounting inside of the transformer tank, but many of the features and benefits our customers appreciate from our UZ on-tank technology. This combination of the best qualities from both types of tap-changer makes the UBB model unique in its design and operation. Primarily designed for the small and medium sized transformer, the unit is compact and cost effective compared to equivalent diverter switch types of tap-changers.

Product scope

  • Base technology: Conventional, resistance, in-tank, selector switch
  • Common applications: Network, special


  Tap-changer placed in the neutral point of the winding Other placements of the tap-changer
Highest voltage for equipment (Um) 76 kV 76 kV
Max lightning impulse (BIL) 350 kV 350 kV
Max current
1-phase (one tap-changer/phase)
500 A
500 A
500 A
500 A
Max step voltage 1500 V 1500 V


Why Hitachi Energy?

  • Compact size reduces overall space requirements in transformer to ensure cost effective solutions
  • Simplistic, reliable design philosophy ensures less complexity for reduced maintenance time and cost
  • Proven contact system has more than 40 years of service experience in more than 25,000 tap-changers

Get to know more

Document title ID
Technical guide 1ZSE 5492-106
Declaration of conformity 1ZSC000498-ABP
Ordering data form (.xlsm)
Please note that this is an interactive form, which can be filled in, saved and sent to us by e-mail.
Ordering data form explanations 1ZSC000498-AAR
User's manual 1ZSE 5492-156
Installation and commissioning guide 1ZSE 5492-118
Maintenance guide 1ZSE 5492-127
Repair guide 1ZSE 5492-130
Spare parts list 1ZSC000562-ACY
Accessories and protection devices 1ZSC000562-AAD
Oil filter unit, type HPS 27/27, 54 1ZSC000562-AAF
Oil filter unit, type OLU 1ZSC000562-AAR

Type designation Drawing number
UBBLT 5492 0088-1
UBBRT, UBBDT 5492 0088-2
UBBLN 5492 0088-3
UBBRN, UBBDN 5492 0088-4

The drawing shows Drawing number
Mounting on active part 5492 0088-8
Lifting tool for active part mounting 5492 0088-7
External drive shaft system 5492 0088-9
Bevel gear 5492 0083-1
Top section accessories 5492 0088-17
Connection of oil filter unit to top section 5492 0088-15
Recommended flange on transformer cover 5492 0088-11
Ball valve 1ZSC000772
Pressure relay 5492 0083-2
Oil flow relay 1ZSC003527-ABB
Pressure relief device - flow diameter 50 mm, standard - Comem 1ZSC003721-AAW
Pressure relief device - flow diameter 50 mm, class C5-M - Comem 1ZSC003721-AAV
Temperature relay 1ZSC003716-AAM
Tie-in resistors for UBBRN, UBBDN (136 kohm) 5492 0050-27
Tie-in resistors for UBBRN, UBBDN (204-300 kohm) 5492 0050-28
Tie-in resistors for UBBRT, UBBDT (136-200 kohm) except for 7-13 pos. 5492 0050-19
Tie-in resistors for UBBRT, UBBDT for 7-13 pos. 5492 0050-34

Movie title ID
Tap-changers by ABB: Based on traditions - geared for change 1ZSC000717-AAM
Life cycle support: Training centers 1ZSC000717-ABD
Tap-changer retrofit: Transformer life extension 1ZSC000717-ABY
It's all about commitment: Life cycle support 1ZSC000717-ACX

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