magnetizing current value - which is acceptable?

Thread Starter


Joined Jan 8, 2018
How to choose the value for magnetizing current? Sometimes i just see "Assume that magnetizing current is 10% of primary current"
Which value is required to avoid saturation?


Joined Aug 27, 2009
What do you mean by chose the value? The magnetizing current generates the flux of the transformer. The exact value depends mainly on the losses in the transformer core during operation.

As you can see (hysteresis curve) from above the flux density is not directly proportional to the magnetizing current because of core saturation. The magnetizing current value has to deviate to keep the flux sinusoidal with a sinusoidal applied voltage. For most power transformers it's perfectly normal to design and run them close to knee of total saturation.