Need source for Hardinge HC powerfeed rheostat

Machine had blown the 1 8/10 amp fuse, figured I must have fed it too hard. Replaced with a 1 1/4 amp, worked fine for a few days then blew again - lighter fuse, must be more sensitive. Replaced with 1 6/10 won't hold at all. Take powerfeed motor apart, rotor wore thru wire, shorted and burned. Repair, try again, fuse still blows. Take apart powerfeed control box, rheostat burned wires off winding at the lowest setting.

I know little about electronics but do know I need at least a rheostat, but will that solve the problem or could it be something like a rectifer or other part? Clearly the fuse did not work fast enough to save the rheostat, but its hard to believe the wires burned at such low amperage.

Any help in sourcing parts is greatly appreciated.

Thanks,

Smoooth