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VFD life expectancy

VFD life expectancy

VFD life expectancy

Our plant is in its 11th years of existence. As i can see, 25% of all our VFD had failure. We do use Allen-Bradley and Toshiba. Of what i can figure out is that 12-13 years seems to be the average life of a VFD. What do you think of that? Does someone disagree ?

RE: VFD life expectancy

I had no idea it could be so high!
The biggest problem with life expectancy on VFDs is in application. They must be capable of doing the job expected of them, they must be kept cool, clean and dry, and they must be kept away from voltage spikes. I have yet to see an industrial application where all of those factors are maintained for any length of time.
As a VFD mfgr / supplier I see that most failures are cause by one or more of these issues.
1) Many users do not truly understand what a VFD can and cannot do for you. Combined with buying from the lowest bidder who may be woefully missinformed, the end user is often left holding the bag on a frequently failed product.
2) The best of intentions about keeping them cool, clean and dry can only be kept up by the most vigilant of technicians. Employee turnover and shifting priorities take their toll.
3) No matter how good everyone thinks their power grid is, it will someday deliver a devastating blow. VFDs are like all other electronic products, except that the spikes and surges are usually a little more raw from the grid.

If you want them to last, think about how you buy them.  Hire an expert to determine if your application will work. Salesmen are often more interested in closing the deal than having it last 25 years. Buy the best enclosure you can, and assume you will not be there to change filters or watch the guy with the hose. Spend a little more for the reactors and/or filters, and check the integrity of surge protection systems often. It will pay for itself in the long run.

Or, buy cheap and often. The heck with reliability. That works well if you expect to be changing jobs next year anyway!

That which does not kill me, makes me stronger... and pissed off!

RE: VFD life expectancy

Many manufacturers quote a life expectancy of five years for the DC Bus capacitors, so there is a clue. Life expectancy is very temperature related (fault conditions excepted)

Mark Empson

RE: VFD life expectancy

Suggestion: The AC-DC, DC-DC, DC-AC converters have their limited Mean-Time-Between-Failure (MBTF) (e.g. it may be 50000 hours), Mean-Time-To-Repair (MTTR), etc. Try to obtain these figures from manufactures. They may or may not have them available. Sometines they guess these figures by their practical estimation, another time they will question you for what application it is needed, etc. You could also become a suspect of industrial spying.

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