Non squeal VFD

What is the actual source of the noise?

I run a 1/2HP VFD and 5HP VFD in the high power side cabinet on my Hurco, and both are virtually silent. The servo dithering is louder than either one.

Most..not all...but most VFDs do NOT squeal. Of all the ones Ive installed over the past 16 yrs...only one..a Hitachi 3/4hp on a drill press squealed.

Automationdirect.com is a very good place for inexpensive drives

The GS1 drives will probably do you just fine. If you need any bells and whistles..the Gs2 drives will suit your needs.

Ive installed probably 75 of them to date....all worked as advertised nicely.

The GS-2 drives typically are used on Lathes to replace bad vari-drives..usually Hardinge lathes. Its cheaper to install a drive than it is to repair/replace the vari-drive..by a significant amount, given Hardinge's rape you/dry pricing.

Gunner

"There are no leftists in mainstream American politics.

Just two right wing parties, one hard right and one softer." Christopher A. Lee, 8/18/2013

Like Gunner said, and you implied, I just had bad luck last time. i also have many VFDs with no noise. But, this is a much quiter level, trying to get less noise than a dot matrix printer.

The problem was two years ago, maybe more. Folks on this group said it was carrier wave and I seem to remember reactor being suggested. But my memory sux and maybe who ever said it was full of beans.

Anyway, should i pop for a reactor? I've bought from automation direct before with good results.

Karl

Karl Townsend fired this volley in news: snipped-for-privacy@4ax.com:

If the squeal is coming from the motor itself, the reactor(s) will help smooth the 'simulated sine wave' coming out of the inverter drive.

Good VFD's divide the stepped waveform up into small enough slices so that the noise is of a high enough frequency not to be heard by us old men, and not annoying to anything but cats and bats and teenagers (a good thing).

I've used the Automation Direct VFDs and also Motortronics, with which I have had very good experience and reliability. No noise from either brand.

Lloyd

you can certainly try a reactor. Though Id buy one on Ebay for much less than a new one. Get as big a one as you can, as you may need it down the road on some other drive...if it doesnt solve your problem.

The 1/2hp drives from AD will set you back about the price of a reactor IRRC..they run about $140 at most.

Gunner

"There are no leftists in mainstream American politics.

Just two right wing parties, one hard right and one softer." Christopher A. Lee, 8/18/2013

You hit the nail on the head about teenagers. i though it was quieter, they threatened to mutiny.

Karl

The later Rockwells I've used had a menu item to change the carrier frequency if noise was evident. Our vendor recommended reactors if

200' or more. Something to do with harmonics on the feed line. Mine were usually about 10' or less. Mitsubishis I have now are quiet except I can hear the cooling fans.

Good luck.

Pete Keillor

I think that the squeal is likely from loose laminations in the stator of the motor -- and likely just right to be resonant at the default frequency of the VFD -- so a change in frequency would likely make a big difference. (An alternative is to force a varnish into the laminations -- but be sure to pick one which will not attack the varnish/enamel on the wires wound on there.) Maybe a very thin epoxy would work.

A reactor might reduce the high frequency part getting to the motor windings -- but is otherwise unlikely to be necessary.

A replacement motor will likely not show the same problem -- even if the same brand. But it might be the most expensive approach.

Good Luck, DoN.

Can you move the drive closer to the motor temporarily, just for experimentation purposes? It's a whole lot easier to remote the control wiring from the VFD back to where the operator is sitting.

Is the pump motor Inverter Duty rated? If you have an antique motor out there, it could sing no matter what you do - they are made to take

60 Hz, Period, and you'll start vibrating laminations with any inverter harmonics.

And then you make hot spots in the windings, and they start shorting internally and provide an escape route for the Magic Smoke.

And if the pump motor's a goner, may be cheaper to replace the whole thing. Variable Speed Pumps for swimming pools are hitting wide use - meaning they're getting seriously cheaper. And the drives are already integrated with the motor, and a pump body and debris strainer.

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My impression has always been that the PWM frequency was simply too low on first-generation inverters; and that while anything built within the past couple decades might well still create some annoyong electrical noise, acoustic emmissions will be at a frequency substantionally above the human hearing threshold

I don' know what the total range of human hearing is, but when I was younger I could hear or be aware of frequencies upto about 20kz. Depending on the sound generator somewhere between 19.5 and 20.5 I would notice it go substantially silent. Now as I have gotten older I have noticed that I can't hear much above about 17.5.

Anyway, the range of human varies with age, and does so noticeably with men in the high frequency range. Also, its possible that some people have a wider range of hearing atleast at the peak level of their physical development. All of that being said, who knows what odd frequencies can be generated by a VFD.

Hmmmm... I'm not sure any of that makes a point, but its some nice anecdotal information to consider. LOL.

Female voices are predominately high frequency.

Men, as we age, tend to lose our hearing at high frequencies first.

Coincidence?

"Bob La Londe" fired this volley in news:4U5Rt.155612$ snipped-for-privacy@fx08.iad:

Bob, I used not to be comfortable in a room with a TV which had a loose bracket on the flyback transformer. The 17.5KHz deflection frequency literally drove me out of the room!

At 64, I can't hear much above 10KHz, and suspect that's diminishing due to my fireworks and explosives activities (and Viet Nam, where I had an eardrum perforated by a nearby and unexpected firing of a Browning .50).

Lloyd

Survival.

"There are no leftists in mainstream American politics.

Just two right wing parties, one hard right and one softer." Christopher A. Lee, 8/18/2013

Try having a claymore go off over your hide. Takes out both eardrums. Trust me.

"There are no leftists in mainstream American politics.

Just two right wing parties, one hard right and one softer." Christopher A. Lee, 8/18/2013

Gunner Asch fired this volley in news: snipped-for-privacy@4ax.com:

I've been within 20M of them on the (so-called) 'safe side'. Yeah, they're loud, even when you're hunkered-down below the projectile path.

Lloyd

Im fortunate I can still hear..mostly. I have however gotten pretty good at lip reading most women. I can hear their voices..I just cant make out what many say. Way above my hearing range.

I had my hearing checked by a pro a few years ago..and he had the chart with my hearing range in his hand..he looked up at me...looked at the chart..and said..let me guess..combat vet right?

The chart had holes in the hearing ranges all over the place. He said only combat vets have a chart that looks like it was hit with a shotgun a couple times..with scattered holes all over it. Its been years since Ive heard a violin.

Shrug.

"There are no leftists in mainstream American politics.

Just two right wing parties, one hard right and one softer." Christopher A. Lee, 8/18/2013

One could get some dope or varnish and drip into the area and re-coat the fins into a firm position. Might be an insulation sheet that is hard with varnish - shaking and making noise.

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