Ive got a Covell OD grinder, with a powered 5c collet work spindle. There is what appears to be a relabled Minarik drive controller mounted on the machine, with what appears to be around a 1/4-1/2 motor running the spindle.
The holidays have given me some time to catch up on my To Do List and this is next. When I brought this home, the motor had been disconnected from the drive, and I simply matched the colors of the wiring and turned it on.
It would run ok, at low range, pretty slow, no matter how fast the pot was set, though it would change speeds somewhat. It would not run at all at high speed, nor would it reverse. It ultimately blew a puff of smoke out of the louvers on the drive, blew the fuses then quit. Generally this is not a good sign........
Opening it up, there is a pair of old style bridge rectifiers made up of 4 diodes, and a medium sized veriac or pot. Nothing appears visibly blown on a quick inspection.
The data plate on the motor has been work smooth from years of operators resting their hands on it, so no data is available.
I know absolutely NOTHING about DC motors, or how they work, and even less about DC drives.
I can do a fast and cheap replacement of the diodes by replacing them with the common Rat Shack rectifiers, and I can ohm out the pot thingy..but what do I do next? Id rather not replace everything if po$$isble though the stuff on Ebay is sorta kida maybe affordable. The grinder is in good shape otherwise and runs smooth, and has a good coolant tank and pump.
Any ideas, suggestions, links to wiring diagrams, types of motors DC motors that need two bridge rectifiers and a pot...
This is one big hole in my knowledge base I really need to fill.
'If you own a gun and have a swimming pool in the yard, the swimming pool is almost 100 times more likely to kill a child than the gun is.'" Steven Levitt, UOC prof.