Back to Back Test of Transformer:
The Back to Back Test of Transformer which consists of two parts namely,
- Back to Back Test on Three Phase Transformer
- Back to Back Test on Delta/Delta Transformers
1. Back to Back Test on Three Phase Transformers:
Fig. 3.52(a) shows the connection arrangement for the Back to Back Test of Transformers. The two secondaries must be connected in phase opposition and in proper phase sequence.
The auxiliary transformer for circulating full-load current is included in the circuit of the two secondaries; it could also be included in the circuit of the primaries. Thus with only losses (core-loss and copper-loss) supplied from the mains, a “heat run” test could be conducted on the transformers.
2. Back to Back Test on Delta/Delta Transformers:
The primaries are normally excited from the mains. Each secondary delta is opened at one junction and a single-phase transformer can be employed to circulate full-load current in both the deltas as shown in Fig. 3.52(b).