DISTRIBUTION MAINTENANCE BULLETIN
B22MB92005
01234567-5-123456789LM
September 18, 1992

SUBJECT: DESIGN CRITERIA FOR CONTACTOR APPLICATIONS

Dear MILNOR Dealer/Service Technician:

In the recent past, we have heard a number of comments regarding contactors used on MILNOR equipment. In specific, we heard that CBW contactors have been providing less than satisfactory service life.

Of course, there have been many statements made about the method by which we pick such contactors which have been erroneous. So I'll take this opportunity to clear up any confusion.

Depending on the size of the contactor, the average mechanical life expectancy is from 15 to 20 million cycles. With a little bit of math, you would find that this equates to upwards of 15 to 20 years of mechanical service in our washer/extractors and CBW's.

But most important is the contact life expectancy. In the example of the 50kg CBW, the rated full load current at 200V 50HZ is 10 amps (for the 50kg CBW, this is the worst case example) while the contactor is rated at 24 amps. The corresponding service life due to this de-rate is 10 years. In real life, the 50kg tunnel does not draw rated current such that the life expectancy is 13 years.

We have heard some quotes "contact life in the CBW of less than 1 year". This is simply not the case and was misquoted from the source.

Allen Bradley is a high quality vendor which has responded to all of our questions and application challenges admirably. We expect their products to work as indicated above, and so do they.

If you have any reason to believe that these products are not living up to their good name, please let me know so we can take appropriate action.

With best regards,

PELLERIN MILNOR CORPORATION



Gary L. Lazarre
Manager
Customer Service

GLL/das