Its odd, again, I fired it up, and the fuse immediatly blew (after the variac hummmed for a second), but once the fuse was gone, the variac worked again. The cap seems to be acting as a short to the variac.
I'm not very familiar with the variac: it was the numbers on it (1-5) for leads, how can I tell which ones are hot, neutral, etc? I was just asuming they were standard....
any other suggestions on to why the fuse is blowing?
I suspect some mistake in the wiring assuming there are no defective components in the system, and assuming the capacitor is near the correct value. The capacitor should not be a motor start type. If you tell the variac brand; General Radio, Powerstat, Ohmite, etc, and also the model; V10, 1156, etc., I may be able to give you the information for the lead connections. But you may also may be able to do a google search for that information and get it a lot faster. It would also be helpful to know the amperage, or HP of the motor, and the capacitor value.