Why no load current in a transformer is high?

Answer 1

A transformer's 'no load' current is not 'high'. On the contrary, it is zero!

'No load' means that there is nothing connected to the secondary (output) of the transformer -i.e. it is an open circuit. So a transformer's secondary 'no load' current is zero! The primary current still has to provide a magnetising current, but that current will be very small.

Don't forget, a 'light load' means little current is drawn, so the load must have a high resistance; a 'heavy load' means lots of current is drawn, so the load must have a low resistance.

Answer 2

there is current flow in the primary winding only not in secondary winding, primary current due to the energization of the core. it is considerably less.

Answer

When we describe a transformer having a 'no-load current', we are describing the current flowing in the primary winding when the secondary winding is open circuited and, therefore, not supplying a secondary current.

The primary 'no-load current' (Io) is determined by dividing the primary supply voltage by the impedance of the primary winding. This impedance is made up of a resistance that is very small in comparison to its inductive reactance and, therefore, the no-load current lags the supply voltage by very nearly 90 degrees. This current can be resolved into a magnetising current (Im), which lags the supply voltage by 90 degrees and is responsible for setting up the magnetic flux in the core, and a current (Ii) which is in phase with the supply voltage, and supplies the losses in the transformer.

Answer 3

No loaded condition the current on the primary side provides only core or iron loss.

there is no current at the secondary winding.

Answer 4

The no load current of a transformer is mostly due to eddy current losses in the iron core.

Answer 5

Mostly eddy currents in the transformer core.