dc electromagnet question?

vick · 2007-09-27T21:31:47+00:00

I have constructed a DC electromagnet for a special use at my shop. Being a electrical contractor I thought this would be simple. (NOT) Made the electromagnet, connected it to a 12vdc power supply at 5 amps and it works great with one problem, it starts to heat up quickly. My desired results was for it to run on a 80% duty cycle. Will resistors keep this heating problem from happening? DC voltage is not something I have dealt with indepth. Can anyone help me with this problem? Vick