Two-Speed Motor

[sii]

We have a ventilation fan in one of our buildings that has a motor tripping the overloads. The motor is a Baldor M1223T

http://www.baldor.com/products/detail.asp?1=1&catalog=M1223T&product=AC+Motors&family=Two%2DSpeed%7Cvw%5FACMotors%5FTwoSpeed&winding=36WGY048&rating=40CMB%2DCONT.

I won't have a chance to get to it for a couple of days but the spec sheet shows the speed as 1725/1140 RPM. What means of achieving the dual speeds am I going to find when I get to it? Dual windings?

 

[sgunsel]

Presumably this is an issue on the high speed, 3 HP. The specs show 24 amps starting current and 4 amps running at full load. Where is the OL set? I'd put an ammeter on and see how many amps it pulls. Could be a mechanical problem - too much friction requiring too much torque.

 

[rcwilson]

On the Baldor web page for the motor, click on Drawings and then the information packet. On page 10, a connection diagram shows it is a two-speed, two-winding motor. For slow speed connect T1, T2, T3, for high speed, connect T11, T12, T13. The two speed starter should have two interlocked contactors, Fast and Slow. No need to short any terminals as is needed on a two-speed, single-winding motor.

Ask if someone changed the pulley size or made other changes that increased the load.