I am currently performing the open circuit test on a transformer at my school to separate the hysteresis loss and the eddy current loss. Thus, I am changing the frequency of the AC current while keeping the flux constant by changing the applied voltage accordingly.
However, the current reading on my multimeter kept fluctuating badly. So, I wanted to know what is supposed to happen in theory and if the no load current is supposed to change when changing the frequency while keeping the flux constant.
Some more context:
The equipment my school has is not great right now. Actually its pretty terrible. The signal generator I am currently using can only give out 5V maximum, and the transformer I have is a dissectible transformer with no specifications. Due to the tiny voltage, the current reading is also pretty tiny too. Like I have to use microamps or milliamps on the multimeter to measure the current. When I said my multimeter fluctuates badly, let me just describe what it does:
Current at 35Hz: Around 3.5mA
Current at 40Hz: Around 3.2mA and it just keeps going up and down constantly
The current going down at 40Hz has screwed up my experiment as that means the power loss due to iron core losses decreased when frequency increased. However, the power loss due to iron core losses is supposed to increase with frequency when the flux is kept constant.
How do I find the no load current on a transformer?