No load current of transformer | No load voltage | vector diagram

No-load voltage and no-load current of the transformer.

No Load Voltage: No-load voltage is the amount of voltage applied to the primary when the secondary circuit of the transformer is left open without load.

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The no-load current of transformer: The small amount of current flowing in the primary winding in the no-load condition of the transformer is called the no-load current. The current flowing in the primary of the transformer at full load is about 2% -5% of the current flowing at no load.


No-load vector diagram : 


no-load-vector-diagram

The no-load current of the elements name:


Working component,

Magnetizing component,



The working component of the transformer is called the active component: 

The working component is in the same phase with the supply voltage and causes core loss (eddy current loss and hysteresis loss), it is called the active component.



The magnetic component of the transformer is called the waterless component:

 The magnetic rising component establishes the mutual flux in the core from 90 degrees behind the supply voltage and is called the waterless component.


Amount of current in no-load condition:

 It has the required turn in the winding during design As a result, it becomes a high-quality inductive circuit Now when all the voltages are applied to a circuit with a high impedance, the counter EMF is generated due to self-induction, limiting the primary current. That is why the amount of no-load current is very low in the no-load condition


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