Basically two types:
1. Copper losses:- when the transformer is loaded, current flows in primary and secondary winding, there is loss of electrical energy due to the resistance of the primary winding, and secondary winding and they are called variable losses. These losses depend upon the loading conditions of the Transformers. Therefore, these losses are also called as variable losses.
2. Iron losses or core losses:-The losses that occur in the core are known as core losses or iron losses. Two types of iron losses are: > eddy current loss
> Hysteresis loss.
The transformer will have the maximum efficiency.
No load losses are real power losses (in watts, not vars), so I'm not sure what you're talking about. If you're trying to parallel a transformer with another one to try to cancel out no load losses, you can't do this. These losses are also called core losses and are the price you pay to energize a transformer.
The no load losses are the losses caused by energizing the transformer. These are constant losses, regardless of loading. This in effect tells you the efficiency of the transformer. (Power in) - (no load losses) = (Power out)
Ideal transformer is useful in understanding the practical transformer..i does't have losses...
Losses due to loading. As more load (more current) is put on a transformer, these losses will increase. They are often referred to as I2R (or I^2*R) losses.
Core losses are losses in the magnetic system of the transformer, such as eddy currents in the core, hysteresis losses, etc. Because of this, the losses are constant, regardless of load, assuming voltage and frequency stay fixed.
That is the maximum efficiency occurs when the copper losses are equal to the core losses of the transformer.
there are several losses in a transformer that prevent it from attaining 100% efficiency. One is core loss, which can be divided into Hysteresis losses, Eddy currents and Magnetostriction loses. see for more details http://en.wikipedia.org/wiki/Transformer#Energy_losses
The transformer can be tested on open and short circuit to find the iron losses and copper losses separately, which uses a fraction of the power than having to run the transformer on full-load.
The no-load current of a transformer is the current which is drawn from the source at rated voltage and frequency even when no actual load current is being supplied.The no-load current is what must be drawn to overcome the inherent and unavoidable losses of the transformer's components. Those losses comprise the primary circuit's resistance (known either as the "copper losses" or as the "resistance losses") and the transformer's magnetic reluctance (known either as the "iron losses" or as the "magnetic losses").Reluctance is the techical description given to the energy necessary to excite the magnetic circuit and overcome its hysteresis, the effects of eddy currents, etc.For more information see the Related link shown below.
Transformer
Iron losses are due to energization of the transformer; they do not depend on the loading of the transformer. They will vary depending on the voltage applied to the transformer. The best model of this is a parallel connection to the ideal transformer winding.