IL 44-751-1
Instruction Leaflet
Page 18 November, 2001
Processing Temperatures
The type DTW tap changer is designed to operate properly in the transformer environment.
However, the transformer manufacturer must not over stress the tap changer, thermally, during
transformer manufacturing and processing. The maximum temperature that the type DTW tap
changer can be exposed to during transformer manufacturing is 125
º
C. If the tap changer will be
exposed to temperatures greater than 125
º
C, ABB should be consulted for technical guidance.
Processing within the temperature range of 105
º
C to 125ºC
should not exceed 48 hours total
exposure time.
Renewal Parts
If renewal parts are required, order them through the nearest ABB representative. Please provide
the item description and the identification numbers (model, style, catalog number) from the unit’s
nameplate.
Repairs
In normal use, the DTW tap changer will not require repairs. We recommend that the transformer
manufacturer be contacted before any repairs are made.
Maintenance
ABB de-energized tap changers require little or no maintenance to ensure proper mechanical and
electrical operation of the switch. The transformer should be de-energized before operating the
tap changer. The external operating mechanism should be inspected for any damage and gears
should be lubricated to ensure proper operation. Operate the tap changer across its full range a
minimum of twenty times to assure proper mechanical operation and cleaning of the contacts.
The above should be performed if the position of the switch is changed for any reason.
W A R N I N G
Before attempting any disassembly or repairs, de-energize the transformer
and the auxiliary power source. Failure to do so could result in personal
injury, property damage, or death.
