Can transformers be operated at voltages other than nameplate voltages?
A. In some cases transformers may be operated at voltages less than nameplate voltage. In no case should a transformer be operated at a voltage above nameplate voltage unless taps are provided for this purpose. When operating below nameplate voltage the KVA rating of the transformer is reduced due to the increase in current. For example a 10 KVA 480-240 transformer can have a secondary load of 41.6 amps, if the same transformer was operated at 240-120 the same current draw of 41.6 amps equates to a 5 KVA transformer.
In some cases transformers may be operated at voltages less than nameplate voltage. In no case should a transformer be operated at a voltage above nameplate voltage unless taps are provided for this purpose. When operating below nameplate voltage the KVA rating of the transformer is reduced due to the increase in current. For example a 10 KVA 480-240 transformer can have a secondary load of 41.6 amps, if the same transformer was operated at 240-120 the same current draw of 41.6 amps equates to a 5 KVA transformer.
