A problem with VFD KBAC 27D

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rashid11

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The highly recommended NEMA 4 2 HP VFD from KB Electronics
continues to disappoint. Induces really bad vibrations in 2 different
motors I got: 2 HP Emerson (3600) and 1.5 HP (1750) Leeson. While on the
knife grinder I made, I can live with it, I got the second motor
to convert my 9x20 lathe to VFD and now the project is dead. Good thing
Grainger has hassle free returns w/o any fees. Not so with KB.

The motors are brand new, so is the VFD.

Throughout most of the RPMs the controller makes the motors vibrate/shake like crazy, with or w/o load on the shaft, even when bolted down to a massive WB. The vibrations only disappear @ top RPMs. The grinder is kind of
OK, as I have it attached to massive plate, but still I am afraid the finish will
suffer.

Any1 with these controllers (KMG uses them) - do you have of these problems ? Are the motors ABSOLUTELY nice and smooth when controlled with this VFD ?

I tried about every setting on the VFD, jumpers and POTs, checked all the
wiring etc. It is set to 220V .
 
I have 3 and all my motors weg 2 hp, leeson 1.5 and a baldor all hooked into KB drives as descirbed above and all wired for 220v. Not one problem what so ever sorry to hear this.


Edit to add: Not sure if Rob fink from beaumont metal works is around here but he knows more about these drives than most folks

sar
 
What type of cable are you using to connect the VFD to the motor? For some reason the little voice in the back of my head is saying "might be the electrical feed".

Just a thought,

-d
 
Interesting. When I started my setup first time (2hp Leeson + KBAC 27D)
motor was not literally vibrating but rather making some jerky movements at start up. I took motor to an official repair dude. He run it and said that motor is OK.
After running my setup for about 30 min. problem disappeared. Now it runs very smooth.
 
Does the motor shake while it isn't attached to the grinder?
 
Yep, both of them shake/vibrate real bad, w or w/o load on the shaft. When I bolted the 2 HP to the grinder, it made it less obvious, but the vibration is still there. The rate of "shakes" is may be 5-8/sec

And of course, this is totally unacceptable on a lathe. I won't have ANY kind of finish with it going like this.

The output of VFD is fed to the motor over 3 feet of 4x16 gage , 3 phase + ground. I use L14 connectors, so that I swap the motors and go from grinder to lathe and back.
That WUZ the plan, anyway. It aint' anymore. Electrical wires checked and rechecked ad noseum. Used some low-pressure compressed air and gently cleaned the interior. Thinking I might have some debris in there.

Checked the 6 IGBTs with a meter. They all give me identical readings accross contacts, so I don't think any of them are blown. Must be something
with the circuits that drive em.

Called KB and had 2 separate guys listen to the motors and both agreed it doesn't sound right at all. 2nd guy felt one of 3 phases is not driven the "other" way (gets only the pos or neg output, but not both). So it will go out to them tomorrow. I have to pay for shipping that-way. They will match the return (Red will go Red and so on).

They WONT cross-ship, even with CC offered as a hostage.

I think I will scrap the idea of going VFD on my lathe. Instead, will go DC. The 2 HP threadmill motor + DC speed controller + enclosure are $175 (including shipping). The 3 phase 1.5 HP motor I got from Grainger is $175 too. It is a almost a tie, with DC having upper hand, as I won't have to swap the contollers when going from grinder to lathe and back. Plus I feel AC motors will never be as smooth as DC.
 
I've got two of these same VFDs. One is driving a 1.5hp TEFC Leeson 1725 rpm motor on a KMG and the other is driving a 2 hp Leeson 3450 rpm TENV motor on my other KMG. Both are fed from 230V single phase in my home shop. Both run as smooth as you could hope for.

Sorry to hear you're having trouble.
 
Bummer about the problem!! How frustrating that must be. I've set-up a few of these drives and have never seen this...or heard about it before. If the drive has dropped a leg, I'm suprised that it didn't shut down with a fault/alarm.

Regardless of the pot adjustments..for me, they run smooth as silk. I can't say enough positive things about them.

There are a lot of us using them, so please keep us posted with your findings. See if you can get a repair report from KB detailing the failure and repair. You don't need a receipt for the warranty claim as the unit is dated on the circuit board and traceable through the serial number.

I'm not sure where you got it. If it came from Beaumont Metal Works....SEND IT BACK for an immediate replacement. They are in stock and ready to ship out as soon as the faulty unit arrives. This saves the warranty repair delay through KB. Plus you'll get the newest/lastest design revisions on the drive which just came out a few months ago.

The case has been changed by adding more accesible ground lugs and the circuit board is totally different. They also have a new owners manual.

I'll be glad to help if I can,

Good Luck,
Rob
 
I also have a KBAC-27D and 2HP Leeson 220V. Never had a problem with it, runs very smooth. I really likr mine.

Hopefully KB Electronics will make it right.

Sorry to hear of problems with yours. Keep us posted.

Kelly
 
Rob,

What do you mean there's new improved designs? They made the drives better?

Funniest damn thing, I juist went out and fired mine up and there seems to be some issues. I think the magic smoke came out of em........

Guess I'll have to send em back..........



































































































hehehe. Just kiddin!

But that is one of the reasons I bought mine from Rob. I might have saved a few bucks had I REALLY searched, but I knew I'd get no better service anywhere else.
 
OK, the drive is in the mail, enroute to KBE.

The FW is 02/1.10 (white sticker on the PIC), PCB: Rev -A00 04.12.05.

Just bad luck, that's all :( Bought it from State-Electric
 
I don't think you will get an answer. This is a six year old thread, and rashid hasn't posted on BF in three years.


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