The Role of Harmonics in Transformers

Harmonics means the mulple freq of the basic freq. eg 100Hz will be the 2nd harmonic of 50Hz if generated due to some reason in the device fed to or generating 50Hz power or Signal.

In transformers these are generated due to:

1.) If the Source Supply is not pure Sine-wave. It then contains hamonics. Even-number multipliers or x2, x4 .. & odd are x3, x5 ..

2,) The transformer itself is Uni-directionally loaded, ie 1/2 wave rectified loads are magnetizing core so the power wave shape will be distorted. If you know Wave-analysis then you know that any wave-shape other than Sine-wave is formed of so many harmonics.

Please go to:

"Sources of Harmonics"

http://globalspec.ip09.com/rd/9z1zmmi1pbp0m71gtrt8j8vqogqva7jb8s51omg17ng

a lot of info is there

You either Introduce Harmonics by bringing in Non-Sinusoidal Primary--OR

Create by loading Secondary Non-Sinusoidally - say Thyristor controlled loads.

If the flux density in the core is below the Saturation Hysterisis Hooks -you are all right, so- to-say.

Heavy unbalances and high peaks cause saturations each cycle-driving input Ampereturns nuts --and causing Magneto-Striction WHINEs. waveforms both at Primary & Secondary are no longer Sinusoidal. Apart from Noise- huge extra Watt losses appear--in Primary/Secondary/core.

Lend an occasional ear to your Transformer--any Transformer!