I plan on using a very large solenoid for a magnetic field experiment. I have estimated what I believe to be the inductance and resistance of the solenoid and, with the desired field to be produced, almost 20 amps will be required. After running a simple simulation, I am not sure how to select the right size of an AC power source. Vendors have them rated by kVA or kW. But do I need to choose one based on the peak value of the sinusoidal waveform or some other measure?