Skip to main content

Posts

Showing posts with the label Single Phase Transformer applications

What is meant by "Balanced Loading" on Single Phase Transformer applications?

Since most single phase transformers have a secondary voltage of 120/240, they will be operated as a three wire system. Care must be taken in properly distributing the load as the transformer secondary consists of 2 separate 120 volt windings. Each 120 volt winding is rated at one-half the name plate KVA rating. For example: A 10 KVA transformer, 120/240 volt secondary is to service an 8 KVA load at 240 volts and two 1 KVA loads at 120 volts each. If the incorrect method is used, winding A will be loaded at 6 KVA, and winding B will be loaded at 4 KVA. These do total 10 KVA but since each winding is only rated at 5 KVA (1/2 of nameplate rating), we have an overloaded transformer and a certain failure.