variable speed motor

Well, I finally got the fellows gear shaper going after many headaches. I had a guy come out to the house and wire it that is an electrician at westinghouse. I figured out how to hook the wires from the motor to the speed control by calling a guy at ge motors in Indiana that was able to give me a wiring diagram for the motor. It is a four speed motor and it had four sets of terminal strips with 3 terminals on each strip. The motor wires were labeled, but over the years, some of the tags on the wires from the controller had fallen off, but some were still there luckily. I was able to use the motor diagram to figure out the numbering sequence on the terminal strips and connect the wires back to the motor on the machine and fire it up as there is no diagram for a ge motor controller as old as this one (1943). I fired the motor up and it tripped the breaker on one of the speeds. Here lately, I have been playing with the machine and cranking the motor up in the different speeds and can't seem to find the speed that wouldn't work. Anybody got any ideas on what's going on ; don't think the motor has fixed itself. Could it have been some trash inside the motor that came out when the motor ran some? Do know that the machine came from a shop that apparently had a foundry in it as I pulled the end off of the motor and it was full of foundry sand.

Hi Tod,
The technology used in 1943 to develop variable or multiple speed motors has long since past into oblivion. I am retired and that machine was before my time by two years. I doubt very seriously if you will find anyone currently involved in any technology related to electric motors or drives that has any idea what you have there. I would suggest you try and find a very old edition of the Electrician's Handbook. Probably around 1950 would be a good year to look for. Even if you are not an electrician you should be able to find your motor type and you could provide this information to some one else who is an electrician.

As for your hit and miss problem, you may have discovered what the cause was already. If the motor is as old as the machine, there could possibly be some insulation breakdown in one of the windings. In such cases moisture often causes a problem in these areas and seemingly disapears when the motor has been run for a while thus building up heat and drying out the motor. This doesn't actually fix the motor, but it does clear the fault. The probability is that somewhere down the road the insulation breakdown will progressively get worse until a major problem develops and takes out the motor permanently. One solution would be to get the motor rewound, but that may also be a problem with a motor of that type and age. It would be cheaper to find a surplus three phase motor and a VFD drive for it that will run on single phase power. There I am assuming you only have single phase, but I'm guessing. A good source would be to go to www.hgrinc.com . Everything they have is online and they will ship stuff. BTW, you can bargain with them on anything they have. Hope this helps.

Dave