Suggestions for a back up VFD

Chris Railey

Chris Railey

Well-Known Member
My KBAC is in the shop being fixed but it hurts having my grinder down. I saw a cheapo VFD listed in another thread and I was wondering if you guys could suggest a cheapo for my set up because I do not have the electrical knowledge to know which one to get. I am learning but not there yet. I have a 1.5 HP 110v motor on mu grinder. At present I do not have 220v as an option. Links are appreciated but plain info is fine too. Thanks....Chris
 
Others will likely disagree, but I say just steer clear of the "cheap" VFDs, and just wait for your KBAC to return. Time and time again, people have called me asking for help with those type VFDs.... usually after they burnt up a motor, and all I can tell you is for anything other then a very casual knifemaker, I recommend just staying away from them..... especially if you have limited electrical knowledge.
 
Patience is not my strong suit. However I am sure you are correct. According to the maker, a $25 part “blew up” perhaps due to over voltage. This part is not covered by the warranty but at $25 I will count myself blessed and pay that plus shipping. I tested the outlet and it has steady voltage. I looked all through the guts of that thing and nothing looked “blown up” to my eye but like I said, I am learning about electronics but still pretty ignorant. When they use words like blown up it makes me worry about damage to my motor but since the motor needs the drive to run I will have to wait until my drive returns. I have ordered an outlet tester to check the ground and stuff plus, a surge protector. I hate waiting especially when I am home and cannot use my favorite toy.
 
When they say "blew up" along with over voltage, it usually means a capacitor has gone out. If that's the case most likely your motor will be OK. Of course I can't be sure, but in my previous life as a computer technician that was the usual case. Replace the capacitor and all should be good.
 
Thanks Sean, that makes me feel a lot better I know you cannot be sure but it was a $25 part so it couldn’t be anything too bad I just do not know how overvoltage happens.
 
I agree with Sean! I can tell you that the KBAC VFDs are TOTALLY dependent on capacitors. Th only repairs I've ever had done a a KBAC was capacitor replacement.
 
With only 120VAC available, you're options are going to be pretty limited (likely 1 hp VFDs or below), so it may not be worth spending too much time and effort on a backup that you're only gonna need for a week or two anyway. If you had 240VAC in your shop, I might give some different advice.

Personally, I have a couple of KB drives as well as a couple ~$100ish VFDs from China, and I could easily recommend either/or, though it's slightly dependent on application. Yes, KBs are high quality, have better support, are easier to set up and use, etc..., but the average import VFDs that you can buy now days are an incredible value for the price, and actually offer a few more features that your KB drives aren't gonna have. Granted, these extra features don't really apply to the average knife maker / belt grinder set up, but I know that if either of my China VFDs blew up tomorrow, I'd be ordering another before the smoke cleared. :D

Of course, you do have to make accommodations for the open frames, the manuals usually aren't great, set up can often be a pain, and customer support is pretty much non-existent (depending on who or where you buy from), but at the end of the day, it's a VFD, and it will turn a motor/spindle. ;)
 
I used a Cheapie on the Disk Grinder I built. I normally wouldn't do that but, I'm out of work so I do what I can with what I have! It has a knob for speed control and I can even reverse it with no extra parts. I bought it on Ebay, I cant remember what I paid for it! But I think it was in the $50 range?? In fact the reason I bought it was because it was so cheap!! Here's a pic of the grinder with the VFD on it. Is it as nice as a KBAC HELL NO!! Will it last as long as a KBAC probably not, does it work sure does!! This grinder cost me about $125 ish for everything! Add 30 more bucks to total for the lights I added to it recently.
20200109_113601.jpg
 
Living in South Africa, I don't even know if we can get KBAC imported, so we make do with what we can get. We have a guy here that supplies us with the appropriate motors and variable frequency drives, and it works just fine. Mine has served me well for about two years now and going well.

20200412_105729.jpg
 
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