1990 c1500 5.7 a/c problem...

I have converted to 134a with a new compressor, new accumulator, new pressure sensor and pressure switch. About two weeks later, I started blowing a 25 amp fuse. When the truck is cool the compressor will run for about 5 minutes and it'll either blow the fuse or the compressor will stop once the truck heats up. Could these symptoms indicate a bad relay? Or does anyone have any other suggestion? Thank you...