Thread: CIM speed in reverse?
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Unread 22-11-2004, 07:12
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Paul Copioli Paul Copioli is offline
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Re: CIM speed in reverse?
Wow, lots of disinformation in this thread. Let me give you some facts.

1. The CIM motor windings are symmetric, so there is no inherent speed difference between forward and reverse. However, there are small differences from motor to motor due to manufacturing tolerances but not enough to notice. We have tested these motors extensively and they have the same behavior in forward and reverse.

2. Matching motors at free speed is perfectly fine. Matching motors at any other speed is fine, too. Please note that if you match at a speed lower than your top speed, then any speed over that matching speed one of the motors will be doing negative work. What this means is that one of the motors will be acting like a generator and not like a motor. What this also means is that one of the motors will be doing all the work when running at a speed above the matching speed.


Now for some of my opinions on your drive problems:

1. The fact that your conditions under load are different than sitting on the table points to either your gear box or drive train. Bent shafts, bad bearings, gear or chain misalignment could all be the culprits.

2. It could also be a bad connection, but usually you can find that problem by just running on the table. To find out if it is a bad motor, systematically disconnect one motor at a time and see if the side you disconnected the one motor from still drives. This happened to us a few times and this method found the problem each time.

-Paul