Are power switches required or desired on KBAC drives? The status lights are on 24-7

LARRYZ10

LARRYZ10

Joined
Feb 6, 2010
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This may not even be a concern but both of my variable drives have an orange status light on forever. I run the drives by lifting the start switch to make the belt/ disc move and use the knob to turn up the speed. There are rubber plugs where a power switch would install but I never put one in because every grinder I saw was being used without one. Everything had worked well for over two years so I was surprised to see a couple drives like mine with the power switches installed and I wondered if those guys knew something that I didn't. They couldn't have gone to the trouble just to save the power for the tiny status light...could they? Is it a safety rule in some shops? I like gadgets so I would install a wind gauge on my drive if it was an option without even questioning its usefulness. Does anyone have any facts...how about theories. I can't see the benefit but I don't want to be the only kid without one.
 
No AC electrical/electronic device that can carry more than 100 milliamps should be without a disconnect power switch. This switch shuts off the power BEFORE it gets to the device. It will isolate the device from any line surges as well as prevent internal failures in the device from turning on equipment or creating a shock hazard. It can be a switched receptacle or a switch on the device itself....but put something in the line between the power source and the device. When not in operation, turn off the power to the device.
 
Normally vfd have an interface terminal block for wiring external controls.

I installed a lot of these in harsh industrial situations, and generally they would be installed in a box next to din rail with terminal strips that had an e-stop wired to the VFD, as well as a breaker + disconnect. At the end of the day we would shut off the disconnect.

These types of things are usually installed ala carte, so they leave it up to the installer/end user to determine installation needs.

I don't think you could hurt one from it being in idle state as most of these units are cont. duty, but I usually would see them installed with disconnect.
 
Wont hurt to pick up the switch. I always shut mine off in case of a surge. Hard enough to get one of these never mind having to get another.
 
I have two KBAC27D VFDs and i've put the forward/stop/reverse, and the power switch on both of them. Works great and with no hassles.
 
It generally doesn't hurt to leave them on. Especially if they are in a cold garage etc. Changes in temperature can cause condensation and damage. Some drives have heaters and fans for this reason.
 
I never bothered. If I anticipate not being in the shop for a while or bad weather, I just turn off the breaker they're attached to. If that's not convenient though and they're hard wired in, definitely I'd want another disconnect.
 
javand said:
I never bothered. If I anticipate not being in the shop for a while or bad weather, I just turn off the breaker they're attached to. If that's not convenient though and they're hard wired in, definitely I'd want another disconnect.
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Circuit breakers don't hold up well when you trip the very much at all. A switch would be better.
 
I am convinced now that switches are the smart move and probably next to necessary. Thank you all for your comments. I ordered two switches from Galco today. There are four wires on them from the picture. Is there anything I should avoid when connecting them? I have seen the photo of the inside of the drive with the switches wired...seems pretty straightforward but I will probably wire it wrong the first time. I guess I will dig out the Kbac booklets that came with he drives. Thanks again, Larry
 
woodwrkr221 said:
Circuit breakers don't hold up well when you trip the very much at all. A switch would be better.
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*shrug* They've held up fine for years now. Cost me about the same to replace as a switch. I'm not saying I wont put switches in eventually, I'm just saying that I haven't thus far and haven't had an issue. Since I've said that publicly, I'll likely suffer a direct lightening strike tomorrow. Although FWIW, when I worked in computer system architecture, I saw numerous cases of massive surges from strikes bridge circuit gaps thru highly advanced and expensive line conditioning equipment. i.e. ultra expensive "surge protection". So, a small disconnect IMHO isn't likely to save you from much of anything serious.

Do what makes you feel safe though. Peace of mind is priceless.
 
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