DISTRIBUTION MAINTENANCE BULLETIN
B22MB92007
01234567-5-XX3XXXXXXXX
October 9, 1992


SUBJECT: 72" SPLIT POCKET WASHER/EXTRACTOR EXTRACT MOTORS


Dear MILNOR Dealer/Customer:

We have recently noticed a rise in extract motor failures on 60 and 72" split pocket machines. About two months ago, we changed our production and spare parts supply to copper bar rotor equipped motors. These motors would reduce the long standing problem of aluminum dye cast rotor failures which have plagued this particular application in the past.

Much to our surprise, we have seen one copper bar motor returned with a "damaged" rotor. Originally, we thought the motor was manufactured improperly, but ultimately found that this E2 motor failed because of an E1 motor rotor failure on the same machine. As you can imagine, when the E1 motor does not accelerate the load completely, the E2 motor must make up the work that the E1 motor does not provide. This would mean that the E2 motor would accelerate the load, in some cases, from drain speed up to high extract speed. The work required is tremendous. Because of this, the rotor on an E2 motor was significantly warped and damaged beyond further use.

It is absolutely necessary for any customer with an E2 motor failure to properly diagnose a potential E1 motor rotor failure. This can be easily accomplished by loading the machine fully and allowing the machine to enter low extract speed while monitoring the current draw of the E1 motor and motor RPM's. At the onset of E1, the motor should initially draw from 5 to 7 times full load nameplate amps. Within 30 seconds, the current draw should be at or below full load nameplate amps, while the motor RPM's is within 3% of motor nameplate RPM's. A rotor failure would typically indicate a current draw of less than 3 times nameplate amps and never accelerate to full speed in less than a minute. In some cases, it is virtually impossible for the motor to accelerate the basket at all.

The cost of misdiagnosing or not diagnosing an E1 motor rotor failure is a subsequent E2 motor failure. As you can imagine, it is impossible for Baldor Motor Company to warrant a motor which has been excessively loaded by accelerating a load from drain speed up to high extract speed.

Thanks for your help and efforts to help distribute this information.


Best regards,

PELLERIN MILNOR CORPORATION



Gary L. Lazarre
Manager
Customer Service

GLL/das