i have posted a few other questions on this topic here and have gotten good answers and advice. i have been working on a project for over a year, i have built a long solenoid coil with an iron core and was trying to power it from a 12 volt car battery with no luck changed my strategy after some advice from a mentor here. he suggested i use a controlled benchtop type of supply, so i have bought a variac power supply, its input is 120 volts ac 50-60 Hz. its output is 130 volts 25 amps maximum. my solenoid is made from #8 gauge enamaled magnet wire. i have used 700 feet. i have connected the output of the variable transformer to a full wave bridge rectifier to convert the ac to dc. the fullwave rectifier is rated for more than 200 volts and 35 amps. my question is this, why does the fuse keep blowing before i get the voltage above 50 volts on the variable transformers voltage gauge?