This example shows how to model a transformer using fundamental magnetic library blocks. The transformer is rated 50W, 60 Hz, 120V/12V and assumed to have an efficiency of 94%, no-load magnetizing current of 1% and a leakage reactance of 2.3%. Core losses are not modeled and the core material B-H characteristic is assumed to be linear.
The transformer initially operates under no-load conditions. At time t=0.5s, the rated load is turned on. Because of the winding resistances and leakage inductances, the secondary voltage drops from 12 Vrms to 11.3 Vrms and the transformer supplies a full load current of 3.9 A rms on its secondary. The flux and mmf scopes show the operating conditions during no-load and full-load. Compare the leakage flux with the core flux, and observe the primary and secondary-side mmfs.