How to calculate no load current of transformer

Transformer Loading Example No1. Calculate the no - load current , Io and resulting power factor. Because of this core loss component, the source current in transformer on no - load condition supplied from the source as source current is not exactly at 90° lags. I am interested in calculating parameters Rc and Xc which we get performing open circuit test.

After this multiplication of resistance ( responsible for core loss).

In recent decade, change in the type of loads and increasing use of power electronic devices with their nonsinusoidal current waveform has distorted the system voltage waveform .

The current supplied by the source to fulfil the core losses of the transformer.

At no load , secondary current becomes zero du. A practical transformer diagram is shown in figure there is no load in secondary side it is open circuited. So that the primary no load current Iis not 90˚ behind the . Now,to answer your question,when on no load , current drawn by secondary is zero. So,the so called image current in primary due to secondary is also zero.

This leaves us with only the current that is required to set up flux in the transformer. As mentioned iron core has inductance and resistance. To simplify our calculations we . In that case, only few skilled workers will be required to build it. Since the secondary of the transformer is open, the primary draws only no - load current , which will have some copper loss.

This no - load current is very small and because the copper loss in the primary is proportional to the square of this current , it is negligible. There is no copper loss in the secondary because there is no . No Load Current is less than Full Load Current. Magnetizing current lags applied voltage by 90°, while core loss is in phase with the applied voltage (Figure 6b). VP and VS are shown 180° out of phase. IH is very small in comparison with Im, and Im is nearly equal to IE.

No - load current , IE, is also referred to as exciting current. Primary current begins to flow. The instrumentation requirements for no - load loss measurements to ensure proper application of the correction formula will be described.