KBAC 27 question

M

MJB206

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Mar 24, 2023
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Hello all

I finished assembling and mounting my Pheer grinder this afternoon. I have the KBAC 27 vfd unit hooked up to a 1.5HP motor running on 110v. I set the jumpers for 2x speed as well as the 1.5HP and the “sensitive” GFI.

I fired it up to run the motor through its paces - once I got to around 8 of 10 on the vfd scale, the fault light came on and it decreased speed a bit. Just wondering if this is normal - and what is the “max” speed setting.

I have the 7” drive wheel but I’d guess that doesn’t matter as the motor isn't providing any feedback to the vfd

Thanks!
 
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That is not normal. What type of motor is it (rpm)? Not sure what the sensitive GFI does, but maybe try without it on a regular outlet if you have one.
 
I've seen it said several times in the forums that a VFD won't run on a GFCI dedicated circuit. Not sure if that's what you're talking about.
 
Hubert S. said:
That is not normal. What type of motor is it (rpm)? Not sure what the sensitive GFI does, but maybe try without it on a regular outlet if you have one.
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Well, I'm an idiot. I just assumed they would have shipped the grinder with a 1725 motor. Turns out it's a 3450. Put the speed adjustment jumper back to 1x and fired it up. It went to 10 no problem. I'm still curious what kind of feedback the VFD gets from the motor to throw a code.
Keith Nix said:
I've seen it said several times in the forums that a VFD won't run on a GFCI dedicated circuit. Not sure if that's what you're talking about.
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On some models, that's correct (i.e. the KBAC 24) - but the 27 is supposed to play well with them if you set the GFI jumper
 
With the 2X jumper in and a 2 pole (3450 RPM) motor as you approach 8 you're hitting over 5500 rpm which can cause issues. Not sure what's causing the VFD to show fault light, but that motor (windings, bearing, etc) sure is suffering at that speed.

Anyway, it sounds like you've got it working now.
 
Ken H> said:
With the 2X jumper in and a 2 pole (3450 RPM) motor as you approach 8 you're hitting over 5500 rpm which can cause issues. Not sure what's causing the VFD to show fault light, but that motor (windings, bearing, etc) sure is suffering at that speed.

Anyway, it sounds like you've got it working now.
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Yeah - not to mention I have a 7" drive wheel, so the belt and platen wheels would really be moving up at that level....
 
Glad you got it figured out. If the belt is moving too fast for your liking with a 7" drive wheel, the KBAC has a trimpot that allows you to dial back the maximum speed a bit (IIRC, you can adjust between 70% and 110% of the motor base speed).
 
Hubert S. said:
Glad you got it figured out. If the belt is moving too fast for your liking with a 7" drive wheel, the KBAC has a trimpot that allows you to dial back the maximum speed a bit (IIRC, you can adjust between 70% and 110% of the motor base speed).
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I recall seeing that in the documentation as well. So far, it seems I’m able to get every speed I need by just adjusting the dial. With ceramic belts it eats up 1084 pretty quick at around 7-8.

Next I need to sort out how to reduce some of the belt bump with the higher grits….I’ve seen a few posts on here about it. It’s my first 2x72, so still a few things to sort out.
 
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