VFDs and GFIs

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PSarganis

Joined
Aug 14, 2004
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First off, love the new speed of the forums. It use to be really slow for me.

I know I've seen threads on this issue, but I can't find them. The search isn't working for me. My question is, does anybody know of a work around of using a kbac vfd with a gfi? I'm plugging into a gfi at a farmers market so I have no other options.

I have a 1.5hp motor (3600 rpm) with a kbac 27 that works fine. I swapped it out for an ironhorse 1 hp (1800 rpm) using a kbac 24 and it pops the gfi. It finally dawned on me that the gfi was the issue, but I don't understand why one would work and the other doesn't.

Thanks,

Paul
 
Thanks Drew! I'll check it out.

I did a search outside of bladeforums and found some info, but no solutions. I appreciate the link and I'll try what you suggested.

Paul
 
Show both data plates.

There can be amperage differences between the two rpm's

Best if there is no GFI on the circuit.

Dedicated fridge circuits are standalone and non GFI
Talk to the organizers and see what they can do.

The other soln is a small generator, but I bet they wouldn't want the noise of a generator.

How long would a car battery or two last ?
Who can figure that out ?
 
I have to see how to post pictures, but I did try different combos of motors with the VFDs in my bathroom GFI.

The original setup with my lesson 1.5hp and kbac 27 works fine. I tried my kbac 27 with the new ironhorse motor (1hp) and it triggered the gfi. I even tried an old 1 hp GE motor and that triggered the gfi. Two reasons for switching and that is I'm afraid I'll burn out my leeson since it's 3600 rpm and I run it slow for sharpening for long periods of time. I don't need 1.5 hp for sharpening either and wanted to use it on another knifemaking grinder.

I have a generator, but don't think they want me using it as I'm next to people with food and no GFI is not an option since it's an outdoor cabinet with GFI outlets.

The doc in the link above says they came up with a solution using software. Can't say I understand that, Maybe they mean firmware. But, I'm going to give KB a call and see what suggestions they have.
 
It popped the gfi with the GE motor also. If I plug into a standard outlet all the combos work fine.
 
Kb makes a vfd designed to work with gfci plugs.
 
I can't remember, and I can't find it on their website anymore... when I was shopping for my KBAC27D I saw it on there... I sent them an email to ask, but I haven't heard back yet. I'll post here either way.
 
They seem to be very slow to respond. I called Wednesday morning and was transferred to someone and had to leave a message, but haven't received a call back yet.
 
Meant to reply to this sooner but forgot my login info🙈 so all kbac vfds made in the last 5 years atleast have a jumper setting for gfci sensitivity.

Ive had atleast 10 different kbacs, 24 and 27 and used them in nice well wired garages and shops to pretty sketchy apartment garages with gfcis.

id have to find the manual but you have a jumper with 3 settings inside the vfd, one is standard, the second is semi sensitive and third is very sensitive. My understanding is it changes the frequency of the drive because that’s what is tripping the gfci.

After I adjusted it my vfd worked on any outlet I tried that was atleast 15 amps
 
My manual (covers models KBAC-24D, 27D, 29, 29 (1P), 45 and 48) says that the J12 jumper is for GFCI on 3G models only.
G1 / GF1 - Standard GFCI
G2 / GF2 - Sensitive GFCI
The factory setting is on the 8kHz switching frequency setting.
"Note: GFCI operation may increase audible noise"
 
Thanks guys. I'll open it up tomorrow and check it out. The only thing my manual says is don't hook it up to a gfci circuit and call sales if you want to.
 
I opened up my kbac 24 and saw that I have a J12 jumper (I bought it in December 2020. It has 4 jumpers and I tried both the gfi ones and it still popped my gfi. I plugged it into a regular outlet and it works fine.

I found a manual on motorsandcontrol.com. Have to look it over.
 
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I talked to tech support today and basically if it doesn't work with the gfi circuit then change to another one. He said it works with most, with older ones working better. So, I'll have to try it at the market and see if it works with their gfi.
 
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Just for others looking for a solution... I plugged my gfi/motor combo in at the market today and it worked. Pretty happy about that. So, all I did was change that J12 jumper to the gfi setting. Third generation kbac vfds should have this jumper.
 
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