scope:

The standard gives service conditions, definitions, ratings, design and construction details, type and routine tests and nameplate details, applicable to on-load tap-changers for p ower transformers and their motor-drive mechanisms. It relat es mainly to oil-immersed tap-changers, but air-insulated ta p-changers are not excluded and the conditions should be sui tably modified. Tap-changers for transformers for railway ro lling stock are excluded from this standard. In selecting a tap-chan------------