Question about KBAC-27D switches and cable ports

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CallumRD1

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Jan 10, 2020
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I've just ordered a KBAC-27D to run a DIY 2x72 grinder but I would like to add an AC interrupt switch to it so I can fully turn it off. The factory part number is 9523 but most places want $29 for it. Does anyone know of a compatible switch that's more affordable?

Also I have the same question about adding liquid tight fittings (more for dust resistance than liquid resistance) at a lower price point. Can anyone point me to a more affordable part?
 
Shucks, I was going to hop over to Amazon and give you a link to a DPST switch just like you need - all I could find was DPDT switches! I was surprised how hard to find a DPST toggle switch!

Ebay was the same way, all DPDT switches. You can always use the a DPDT and not wire in the bottom contacts. https://www.amazon.com/dp/B07LBMMN2Y/ would give you 3 of the switches, one for the ON/OFF and one for FORWARD/REVERSE switch.
 
What Ken said is how Dan Comeau wired his. He has a tutorial here in case you have not seen it. He also has a tutorial on wiring the forward/reverse switch here. I think Mouser has a DPST that might work but it is $22 before shipping.
 
Actually, there is a bunch of switches on Mouser that are a good bit cheaper and might work. I don't have the exact specs and cannot find them on the web. If you have the specs, you can use the filters on the Mouser website and narrow it down pretty quickly.
 
Ken, do you think it's important to get a sealed switch? They have the little rubber/silicone boots on Mouser as well for around $2 a pop. Is that enough protection?
 
Fwiw,
We use ordinary switches like you might have on your wall. Look beyond whats on hand at the Big Box store. All manner of electrical configuration is available.
Works great provided you are not stuck within physical space limits.
Said that,
They are installed vertically in dry albeit filthy environments. No failures from dirt ingress yet...
 
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Since the switch is going to be enclosed inside the NEMA 4X VFD housing I doubt seriously any dust to speak of would ever get inside the switch thru the toggle lever. If it did after a few yr it wouldn't be any problem to replace the switch "IF" it ever fails due to dust. BUT, a silicone boot isn't expensive and would match existing switches. I'd most likely opt for the boot, not so much as a "need" but to match rest of drive switches.
 
I just now finished wiring up my KBDA-27D, same ports, terminals inside, etc. I wimped out on plugging it in, decided I'd wait until I asked a question about it that I'll post separately. Here's what I found when searching for the connectors and a bit more about the actual wiring that might help:

You can get two 1/2 NTP glands, matching nuts and some sheet rubber to cut gaskets from for $10 plus $5 shipping from zoro.com. That's cheapest I found. If I didn't have some rubber sheet already and other stuff to order that hit the $50 free shipping, I would have just got the KB kit.

For the smaller holes you can use 1/2 NTP cable glands.
1/2 NTP cable glands fit the smaller two holes and a 3/4 NTP cable gland fits the larger - you only need two, one hole gets plugged up with one of the two plugs shipped with the VFD.

I was unfamiliar with NTP thread sizes and was thrown off by how much larger diameter the threads are than the number indicates - based on the pipe ID, apparently. Probably common knowledge but I almost ordered the wrong ones. The OD on the threads is ~.8, if you look for rubber washers instead of gasket material. I saw some sealing washers intended for this somewhere, don't recall where.

1/2 NTP for smaller holes, Cord Dia. Range: 0.17" to 0.45" (make sure that fits your cable):
https://www.zoro.com/hubbell-wiring...-conn-017-045-strt-1-cord-sec50ba/i/G1693921/

1/2 NTP Lock nut:
https://www.zoro.com/hubbell-wiring...tor-locknut-nylon-12-in-31622003l/i/G0746347/

If you want to use the larger hole:
3/4 for larger hole, Cord Dia. Range: 0.45" to 0.71"
https://www.zoro.com/hubbell-wiring...-conn-045-071-strt-1-cord-sec75ba/i/G1851211/

3/4 NTP Lock nut:
https://www.zoro.com/hubbell-wiring...tor-locknut-nylon-34-in-31622007l/i/G1572453/

They have others for other sized wires, ones that make 90 degree bends, and some that cost more but include nuts and washers, just search "liquid tight connector 1/2".


Some info on the wiring, in case it's useful to help you have stuff on hand when the VFD arrives:

I got 12/3 and 14/4 SJOOW cable. I think the manual says 14/3 would have worked (check, don't count on it). If so I would do that next time. 12 AWG is a bit thick to find crimp on terminals that fit (more below) and almost hard to fit around the stud on it's own. Home depot near me does not carry 14/4 and was out of 12/3 and 14/3 - then messed up the order when I ordered it. I ended up adding it to a McMaster Carr order and spending a bunch extra since their minimum length is 10 feet.

There's a thread here that discusses how to physically wire the vfd, with some saying to use ring terminals instead of just the stripped wire end. This is awkward because the 12 or 14 AWG wire is a bit large for the size of ring terminal that would fit (3.5mm / #6 stud and maximum ring diameter around 0.325"). I found some locally for 14 AWG but not 12 AWG wire. I ended up calling KB and asking the tech, he said they just use the wire end, no crimped on terminals.

I like the security of ring terminals so I used them on the motor wires and will order some from mouser.com for the AC-in wires. They sell them individually for ~$1.00 each, plus $8.00 shipping (at least to my location).

The ground terminals in the VFD have 4mm studs and the ring has to be no wider than about 8.5mm to fit in the rimmed washer. You might check to see what you'll need for your motor junction box as well. I needed wire nuts and a larger ring terminal for ground.

Another note: the tech also mentioned that if the VFD has been sitting for over a year you should plug it in and NOT RUN IT for one hour to "reforming the capacitors". I figure that's an easy step to take just in case since I don't know how long it was at the warehouse. Just passing that along.

Sorry for the long post, hope it saves you time hunting.
 
Just for reference, a DPDT switch can be used as a SPDT switch by merely using only one side. I often use the other side is often used to light an indicator lamp with a green lens/LED to show "Main Power-ON".
 
Stacy is correct that a DPDT switch is easy to use as a single pole switch. The OP was asking about the main power switch which really needs a DPST (OFF-ON) that has two poles to break BOTH power legs.
 
Good find on ebay Stacy, I looked but didn't find any on ebay. Your "search" is better than mine:)

I had thought about the use of a DPDT and would use it myself if needed, but was hesitant to suggest for anybody else due to the 3 positions with one position not used. There is a DPDT switch that is ON-ON with no middle OFF position that would have been just fine.
 
Thank you all for the help. I ended up ordering a DPST for the on off switch and a DPDT for the forward-reverse switch from eBay.
 
Stacy, Like I said, your search is MUCH better than my searching yesterday. When I first posted to thread I'd planned to hop over to Amazon (or other places) and find exactly what was needed, but it just didn't turn up. I'm usually confident in my search ability on-line, but not that time. I even checked DigiKey with no luck, then Mouser with limited success. I've purchased electronic components from both those places for years.
 
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