Just repaired a Variable Speed Motor Drives

[sam_sam_sam]

I just had to repair a Variable Speed Motor Drives (AC ) that is 12 years old it had two bad cap on the current sensing board 47uf @ 16 volt

This board cost $418.00 and there is a 2 week lead time and a week to get to where I am

If you want to see what the board looks like here is a link where there is a photo of one

http://item.taobao.com/item.htm?id=10372034692&

My BOSS is very happy that I could fix this board until we can get another board to have a spare one

The current sensing modules they are made by Honeywell But I can not find the ones I need

Here is what the problem with this drive was when it cooler in the AM the drive would go in to an ground fault alarm every time you would start the the drive to run the motor

But here is the funny part of this.....>
One cap had a ESR reading .57 @ 80 *F but at about 60 *F then it when to .75 and going higher the other cap was .51@ 80 but at about 60 *F then it when to .70 and going higher

The FR caps 47uf @ 25 volts I put in I did the same test and had a ESR reading .47 @ 80 *F but at about 60 *F then it when to .51 and stay there

This is the second or third time I have seen this type of failure

[budm]

Re: Just repaired a Variable Speed Motor Drives

Great works, ESR of the cap goes down as the temperature goes up, that is why hair dryer is a good tools for finding bad cap with high ESR.