Which VFD? 110V input, 1.5hp motor

Samuel Goodhue

Samuel Goodhue

Joined
Nov 26, 2018
Messages
84
Hey everyone,

I know that VFD threads have been done a million times before, but I'm looking for advice on which specific make/model of VFD will fit my needs and I can't seem to find anything that clears it up.

I'm currently running a 1hp motor on my belt grinder. It's set up in a direct drive configuration, No VFD, 4" drive wheel.

I'm thinking about upgrading to a 1.5hp motor and a VFD. I've got a dedicated 110V 20amp circuit to work with in my studio and my question is this... is a KBAC27 my only choice for a VFD?

I ask because every other less expensive VFD that I can find(like the Teco) seems to be either 110V input with a 1hp max, or 220V input with a 2hp(or more) max. Is the KBAC27D the only VFD that can take 110V power and run a 1.5hp motor?

If Im misunderstanding something please let me know, my experience with electrical stuff is very limited.

Thanks,
Sam
 
As far as I know, the KB drives are the only ones that can run 1.5 HP motors on 110V. They offer a digital version in a similar price range (KBDA-27D), also in a NEMA 4 enclosure. I like the KBAC-27Ds, they are very easy to wire and appear to be very well built. You will love variable speed.
 
As far as I know, that is correct, the KBAC drives are the only drives to accept 120vac input for 1.5hp motor. I'd get a 2hp motor and derate it to 1.5hp to run on 120vac input, then if you ever get 220vac available you've got 2hp.
 
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Ken H> said:
As far as I know, that is correct, the KBAC drives are the only drives to accept 120vac input for 1.5hp motor. I'd get a 2hp motor and derate it to 1.5hp to run on 120vac input, then if you ever get 220vac available you've got 2hp.
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Does this derate on 120vac hold true for a 1750rpm 2hp, same as a 3600rpm 2hp?
 
I see non sealed units online that show 1500 kw as the max, can those run a 1.5 hp motor? I also see some 2200 kw as the max, but they show 3 phase 110v output. Is 3 phase 110V a thing?
 
Not really. Depending on Delta or Wye you can have a 110, 208, 220, or 240 volt leg, but the actual 3-phase voltage to a motor will always be 220 or more.
 
Thanks! I've seen the 3 phase 110v output a few times on overseas vfd and didnt know what that meant! I want to convert my bandsaw to a vfd.
 
JV Knives said:
Don't waste your money on a non-sealed unit...dust and VFDs don't mix :)
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unless you do like Brian House shows where you take the VFD apart and put it in an ammo box to isolate it from the metal dust. I don't participate on the FB group House is active on, enough to know if guys are seeing short life on these much less expensive VFD. But I have to assume they hold up fairly well when modified correctly. On that FB group "DIY Belt Grinders & Machines" seems the majority of guys are going the route of the cheaper VFD and modifying them, from a look real quick just now of the builds posted.
 
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I've been running my cheapo VFD since Feb 2021 and it's a non sealed unit. I use a remote cord to run the small, detachable control panel mounted onto my grinder and the VFD is on the other side of a tarp/partial plywood wall away from my grinder, so only very light dust filters through to that area and it's not the heavier metal dust. I hope I didn't jinx myself! I do want to redo the wiring and make a protective box for it down the road.
 
oceanrider said:
unless you do like Brian House shows where you take the VFD apart and put it in an ammo box to isolate it from the metal dust. I don't participate on the FB group House is active on, enough to know if guys are seeing short life on these much less expensive VFD. But I have to assume they hold up fairly well when modified correctly. On that FB group "DIY Belt Grinders & Machines" seems the majority of guys are going the route of the cheaper VFD and modifying them, from a look real quick just now of the builds posted.
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I think any method that gets the sensitive portion of the drive protected works fine. Ammo cans are know for their robustness and sealing so they are a cheap alternative, I suppose.

I have also heard lots of guys running them unprotected with no issues, like above. That's not my luck. Mine would short out at the worst possible time, so I try to pass along advice from my world :)
 
Many of the cheap VFD's control pad is actually removeable from the VFD itself and you just need to have the right extension cable to run it further away. Often, the manufacturer has them available or can tell you the connectors you need, but may not advertise them online. It's typically a ribbon type cable with 5 or 10 pin connectors on the ends. Get some long ribbon cable, and match up the connectors and make your own cord if you can't find one online. Then you can mount the VFD away from the grinder/dust.

Supposedly it's the metal dust that gets sucked in and fries/shorts them, so even mounting it away from the grinder may help increase life without having to put it in a box. No dust is good to get in there, but the metal dust is really bad and can cause shorts! From what I have seen, most of the metal dust doesn't travel as far as wood/handle dust due to it's weight. The VFD's have fans for ventilation, so they can suck the dust inside if they are too close, so even some distance away from the grinder and some sort of barrier between the vfd and grinder will be sufficient. Even making a rough box with plastic sheeting and paint stir sticks as a frame will probably work if it's several feet away. The KBAC27-d are expensive and were hard to get for a while, so I went the cheap VFD route instead for now. It's nice to see a less expensive 110V to 220V VFD available now! I didn't see that option a couple years ago when I got mine.
 
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