How to prevent VFD failures

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vikasnar

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I have a knitting and dying plant and I am experiencing lot of VFD failures (15-18 in a year) Overall a plant has 95 VFDs and I am really surprised by so many failures.

what all I need to do/check to prevent failures and increase reliability?
What is Average life of VFDs?

Vikas
 
pton makes a good point about the cooling.
I haven't been to a knitting plant by my experience with other textile plants, dust from fibers can be a bit of a problem.
Vikas, have you had any feedback on the nature of the failures? You need to have some idea of what's gone wrong in order to determine
Are all the VFDs from the same manufacturer?
Are they low power? There's a lot of low cost kit of sometimes debatable quality at the low end of the market.
 
Besoeker said:
pton makes a good point about the cooling.
I haven't been to a knitting plant by my experience with other textile plants, dust from fibers can be a bit of a problem.
Vikas, have you had any feedback on the nature of the failures? You need to have some idea of what's gone wrong in order to determine
Are all the VFDs from the same manufacturer?
Are they low power? There's a lot of low cost kit of sometimes debatable quality at the low end of the market.
Click to expand...

All true.
My main beef with ASD 'application' is that it is often done by a salesman. How many times a manager have heard: Boy have I got a solution for you that will save you a TON of money! So the manager does what they do best: DO IT TO IT! All ASD applications should be done by different level of expertise.
Have an expert review all of your applications if this was not done initially. Do a root cause analisys.
Your failure rate is way beyond tolerable.

There is one thought though: if all these drives are 10-15 years old and the application is properly engineered, you may be experiencing capacitor failure, for which there is no cure but replacement. On small drives it may be more cost effective to replace the drive, since it could be obsolete and you would be seeing other type failures as well with aged drives. The old drives also had poor tolerance for surges. Surges effects are cummulative and lead to eventual failure. If the drives are large and were added increementally throughout the years, you may have a harmonic 'polution' problem that could effect other electrical components within your system.
 
weressl said:
My main beef with ASD 'application' is that it is often done by a salesman. How many times a manager have heard: Boy have I got a solution for you that will save you a TON of money! So the manager does what they do best: DO IT TO IT! All ASD applications should be done by different level of expertise.
Click to expand...
We are suppliers and system integrators, mostly for variable speed drives.
My experience is that the applications fall broadly into two areas.
The first is for energy savings, typically pumps and fans.
The second is on processes that actually need variable speed in their operation like paper making machines, textile lines etc.

I suspect that the drives in the knitting plant may fall into the second category.
Maybe Vikas will come back and provide some more information on his application.
 
boboelectric said:
Are they Allen -Bradley?
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Not sure if your question was directed to me?
If so yes, we sometimes use Allen Bradley but more for PLCs (Rockwell Automation) than VSDs.
We are approved system integrators by many of the mainstream manufacturers.
Very often the choice is dictated by our customer who may have an installed base of one particular type. Familiarity with the product and spares inventory means this can make sense from their perspective.
And sometimes, for non-standard applications, we offer our own.
 
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