TRANSFORMER ON NO LOAD

In practical two types of losses happens in transformer 

1.cu losses       2.iron core losses

When their is no load on transformer following properties occur.

1. hysteresis losses increased

2. Cu losses produce in primary 

3. I will be leg by voltage so power factor decreased ,two type of current transformer produce 

where Iw is cu and iron losses and Im shows magnetizing current 

4.At no load the magnetizing current will be very less than Primary full current so losses will be very less at no load condition

TRANSFORMER ON LOAD 

When load is connected with a transformer so I2 will be start moving towards secondary coil, if the load is non inductive so both current and voltage will be in phase if inductive voltage will lead if capacitive then I will lead.

Secondary current will produce its own current that current will produce flux opposite to the primary coil flux which will be greater than primary flux,so in primary voltage will be increased to equalize or neutralize the secondary coil flux 

if their is any change in current same phenomena will be done if load current increased by primary current rating then transformer will move towards saturation