Info on a Master Electric Motor

[GHaulk]

Does anyone know where I might be able to find a wiring schematic for a Master motor that was probably manufactured in the 40's? I have the nameplate info. It is a 440V 3 phase AC motor, but it has 14 leads. The nameplate also has ratings for 4 different speeds at 440V. This leads me to believe it is a 4 speed motor, but I don't know how to wire it without a diagram. Any Help?

 

[jraef]

Not likely. The internet was still pretty much in it's infancy in the 1940's....

Seriously though, Master Electric Motors was bought by Reliance in the 1950's, so it's highly unlikely that any documentation has survived that long. You might try calling Baldor (who recently bought Reliance from Rockwell) but they are unlikely to have taken on records for any more than just the most recent of Reliance's products.

It's also not necessarily a great idea to try to use that motor if it has been sitting idle for a long time either, so you should take it to a motor rewind shop to be checked out. They will be able to provide you with connection information when they are done.

 

[GHaulk]

That's what I thought. Al Gore wasn't old enough then to have invented the internet. Ha, Ha. I have placed a call to Baldor and they are looking into it. I did consider contacting our motor repair shop for info as well. I was just wondering if anyone had any additional info. Thanks for the reply.

 

[oftenlost]

what are the lead numbers? 14 leads strikes me as odd but I have several older GE pubs that might give us a hint.

 

[waross]

There are two basic ways to design a two speed motor. One method is to change the number of poles by reconnecting the windings.
The speed ratios are generally 2:1. (3600/1800)
The other method is to wind the motor with two complete windings with different numbers of poles. Now you can have any two standard speeds. (3600/1800/1200/900)
A long time ago, in a text that was old then, I remember seeing a description of a 4 speed motor that used both methods.
A 2 pole 3600 RPM winding that could be reconnected for 1800 RPM and a 3 pole 1200 RPM winding that could be reconnected for 900 RPM.
The double winding required a special or an over sized frame.
Some of the leads are probably common to both windings.
The frame will probably have exceptionally good torque. Even better than single speed motors of that era which had more low end torque than modern motors.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[dbaird]

Just a thought.... go to:

http://www.easa.com/

Website and under "find a member"

"Search Active Membership
(Repair or Service Center/Distributor)"

It will prompt you for a country and/or state. Once you find your locality call some of these motor rewind shops. Some have been doing business for years and just might have an answer and/or solution for you.

David Baird

Sr Controls Designer
EET degree.
Journeyman Electrician.

 

[GHaulk]

Not sure if this worked, but I have attached a picture of the Motor ID plate. Maybe this will help.

 

[oftenlost]

Looks like a standard 4 speed, two winding constant torque motor. These would normally have only have six leads per winding, each set of six capable of switching from 2Y for the high speed to 1 Delta for the low speeds. I do not understand the other two leads unless you have heaters or thermal overloads. Are all the leads of the same insulation?