CAUTION
ABB recommends that only service engineers with appropriate skills regarding on-load tap-
changers carry out the repairs.
ABB recommends that only maintenance engineers trained by ABB carry out contact re-
placement.
During service
WARNING
Small amounts of explosive gases will always come out from the breathing devices
(dehydrating breather or one-way breather). Make sure that no open fire, hot surfaces
or sparks occur in the immediate surroundings of the breathing devices.
If a failure in power supply occurs during operation, the operation will be completed
when the power returns.
The hand crank must not be inserted during electrical operation.
If the on-load tap-changer is not in its exact position and the hand crank is pulled out,
the motor-drive mechanism will start and go to the exact position if the power supply
is on.
CAUTION
After a pressure 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
the respiratory organs and the eyes. After long and repeated contact with transformer
oil skin becomes very dry.
Used on-load tap-changer oil from diverter switch housings and selector switch
housings contains harmful substances. Fumes are irritating to the respiratory organs
and the eyes and are very easily set on fire. Used transformer oil may well be carcino
-
genic.
Avoid contact with the oil as much as possible and use oiltight protective gloves
when handling the oil.
First aid:
Skin contact: Wash the hands. Use skin cream to counteract drying.
In the eyes: Rinse the eyes in clean water.
Swallowing: Drink water or milk. Avoid vomiting. Call a doctor.
Collect used oil in oil drums.
Waste and cleaning up: Should be absorbed by an absorber. Treat it as hazardous to
the environment.
Upon fire: The fire should be extinguished by using powder, foam or carbon acid.
