3 Phase 230v VFD nuisance trips 120v GFI

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V02maxed

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I'm looking for any suggestions or input. I have several small conveyors in our plant that use 120v to power an AB Powerflex 523 VFD to run a 3 phase motor 230v. The issue is we are in a washdown facility and most of our 120v receptacles are GFI in the production rooms. The conveyor will trip a GFI almost immediately on any GFI outlet we try, with any of the conveyors.
We use Hubble 20amp GFI outlets.

Has anyone run into this before and does anyone have any methods for avoiding this nuance tripping? We are going to try a line conditioner from Isatrol in the panel with the VFD but haven't yet. We use VFD high voltage motor cable with shielding following AB wiring/grounding instructions.

Any ideas would be great. Thanks
 
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Possibly the surge protection devices on the VFD input are causing enough current from line to ground rather than from line to neutral that it does not take much added noise to trip the GFCI?
 
V02maxed said:
I'm looking for any suggestions or input. I have several small conveyors in our plant that use 120v to power an AB Powerflex 523 VFD to run a 3 phase motor 230v. The issue is we are in a washdown facility and most of our 120v receptacles are GFI in the production rooms. The conveyor will trip a GFI almost immediately on any GFI outlet we try, with any of the conveyors.
We use Hubble 20amp GFI outlets.

Has anyone run into this before and does anyone have any methods for avoiding this nuance tripping? We are going to try a line conditioner from Isatrol in the panel with the VFD but haven't yet. We use VFD high voltage motor cable with shielding following AB wiring/grounding instructions.

Any ideas would be great. Thanks
Click to expand...

I'm obviously missing something here - 120V power for a 230V motor?
120-0-120 maybe?
 
V02maxed said:
I'm looking for any suggestions or input. I have several small conveyors in our plant that use 120v to power an AB Powerflex 523 VFD to run a 3 phase motor 230v. The issue is we are in a washdown facility and most of our 120v receptacles are GFI in the production rooms. The conveyor will trip a GFI almost immediately on any GFI outlet we try, with any of the conveyors.
We use Hubble 20amp GFI outlets.

Has anyone run into this before and does anyone have any methods for avoiding this nuance tripping? We are going to try a line conditioner from Isatrol in the panel with the VFD but haven't yet. We use VFD high voltage motor cable with shielding following AB wiring/grounding instructions.

Any ideas would be great. Thanks
Click to expand...
When you say it will trip immediately do you mean as soon as you plug it into a GFCI protected outlet? If so has the drive even started yet when doing this? Might not be the drive but rather the power supply cord has a ground fault. Wash down area - and wicked water into the supply cord? I'd try a new cord, can't hurt and isn't that expensive either. You can meg the cord, but make sure to unhook it from drive first.
 
Besoeker2 said:
I'm obviously missing something here - 120V power for a 230V motor?
120-0-120 maybe?
Click to expand...

Small drives, up to 1HP, are available with voltage doubler circuits. This allows small 3ph 208/230V motors to be operated from a 120V circuit.

If the GFCI is tripping, my bet is on water infiltration; it's washdown. Or, as others have said, the surge protection devices in the drive are leaking too much current to ground. There's a chance it's noise-related, but that's doubtful. Unlike the older GFCI receptacles, modern GFCI's are pretty good at rejecting noise.



SceneryDriver
 
ptonsparky said:
I believe they have a small step up transformer included in the package
Click to expand...

No, there is what's called a "voltage doubler" circuit on the DC rectifier side that is a set of diodes and capacitors that boosts the roughly 165VDC from the rectifier to 330VDC for use by the inverter, which is the peak voltage needed for 230VAC output.

It's a well established fact that the vast majority of GFCIs will trip from the common mode noise created by VFDs and that is made even worse by the voltage doubler. In many cases adding a line isolation transformer helps. For that reason I usually recommend that if someone wants to use a VFD for something that will require being plugged into a 120V outlet that is protected by a GFCI, don't buy the 120V input version with the voltage doubler, buy the 240V version and add a shielded isolation transformer to step up from 120 to 240VAC because you are likely going to need the transformer to ward off the nuisance tripping anyway. And just to be clear, it won't matter if it's a GFCI breaker vs receptacle.
 
Jraef said:
No, there is what's called a "voltage doubler" circuit on the DC rectifier side that is a set of diodes and capacitors that boosts the roughly 165VDC from the rectifier to 330VDC for use by the inverter, which is the peak voltage needed for 230VAC output.

It's a well established fact that the vast majority of GFCIs will trip from the common mode noise created by VFDs and that is made even worse by the voltage doubler. In many cases adding a line isolation transformer helps. For that reason I usually recommend that if someone wants to use a VFD for something that will require being plugged into a 120V outlet that is protected by a GFCI, don't buy the 120V input version with the voltage doubler, buy the 240V version and add a shielded isolation transformer to step up from 120 to 240VAC because you are likely going to need the transformer to ward off the nuisance tripping anyway. And just to be clear, it won't matter if it's a GFCI breaker vs receptacle.
Click to expand...
. The small demo model I have on my shelf has a transformer ahead of it, no doubt doing what you suggest.
 
ptonsparky said:
. The small demo model I have on my shelf has a transformer ahead of it, no doubt doing what you suggest.
Click to expand...

Not all VFD mfrs offer a voltage doubler version. I have collected several small obsolete VFD demo units over the years complete with fractional HP motors. Some have the voltage doubler built into the drive, some have a little cord connected voltage doubler, some have a transformer. If I plug any of the ones with a voltage doubler into a GFCI outlet, the GFCI trips 90% of the time. If I plug in the ones with a transformer, most do not. I've noticed however that even the transformer versions will trip a Sq D Q0 GFCI breaker for some reason. Not all GFCI circuits are created equal I guess.
 
kwired said:
When you say it will trip immediately do you mean as soon as you plug it into a GFCI protected outlet? If so has the drive even started yet when doing this? Might not be the drive but rather the power supply cord has a ground fault. Wash down area - and wicked water into the supply cord? I'd try a new cord, can't hurt and isn't that expensive either. You can meg the cord, but make sure to unhook it from drive first.
Click to expand...

No, the drive starts and after about 2-3 seconds the GFI snaps off.
 
SceneryDriver said:
Small drives, up to 1HP, are available with voltage doubler circuits. This allows small 3ph 208/230V motors to be operated from a 120V circuit.

If the GFCI is tripping, my bet is on water infiltration; it's washdown. Or, as others have said, the surge protection devices in the drive are leaking too much current to ground. There's a chance it's noise-related, but that's doubtful. Unlike the older GFCI receptacles, modern GFCI's are pretty good at rejecting noise.



SceneryDriver
Click to expand...

Thanks for your reply although even on brand new conveyors that we are setting up in the shop, I have to find a standard non GFI outlet to test the conveyor before ever getting near water. I can power up the drive for parameters, but cannot start the drive or it trips the GFI.
 
GFCIs are rated for personnel protection OR equipment protection. We use 'equipment rated' GFCIs on heat trace, for example. Make sure you are using 'equipment rated' GFCIs.
 
Jraef said:
Not all VFD mfrs offer a voltage doubler version. I have collected several small obsolete VFD demo units over the years complete with fractional HP motors. Some have the voltage doubler built into the drive, some have a little cord connected voltage doubler, some have a transformer. If I plug any of the ones with a voltage doubler into a GFCI outlet, the GFCI trips 90% of the time. If I plug in the ones with a transformer, most do not. I've noticed however that even the transformer versions will trip a Sq D Q0 GFCI breaker for some reason. Not all GFCI circuits are created equal I guess.
Click to expand...
If the QO GFCI tripping on ground fault or because of low magnetic trip setting? Standard QO single pole breakers have low magnetic trip and don't always play well with inductive loads.
 
ghorwood said:
GFCIs are rated for personnel protection OR equipment protection. We use 'equipment rated' GFCIs on heat trace, for example. Make sure you are using 'equipment rated' GFCIs.
Click to expand...
Problem is when using 15/20 amp 125 volt receptacles - you might not be able to get around not using GFCI protection.

Best solution is to avoid using 15/20 amp 125 volt receptacles, but I think that may get a little tougher with 2017 NEC.
 
kwired said:
If the QO GFCI tripping on ground fault or because of low magnetic trip setting? Standard QO single pole breakers have low magnetic trip and don't always play well with inductive loads.
Click to expand...

According to Schneider Electric's FAQ website:
"... above explanation comparing the standard breaker to the high magnetic breaker applies to 1-pole, 15A and 20A, QO, QOB, QOU, HOM and CHOM breakers only. Other ampere 1p breakers, and all 2-pole and 3-pole versions are already high magnetic as standard. (Breakers with suffix GFI, AFI, CAFI, or DF are not available as high magnetic).


In a different FAQ they say:
"Because drives produce high level of leakage current, and depending of the sensibility of the breaker, tripping can occur.
At the start up of the drive, the capacitor bank is charging and we see the peak of leakage current. This peak is higher when there is more than one drive after the breaker.
Also, it's dependant on many installation parameters such as motor cable type, motor cable length, switching frequency, motor, ground connection.
To avoid the random tripping of breaker due to earth leakage it is recommended to use GFCI called full immunized type A "SI" which is reinforced against high frequency leakage current."
 
jim dungar said:
According to Schneider Electric's FAQ website:
"... above explanation comparing the standard breaker to the high magnetic breaker applies to 1-pole, 15A and 20A, QO, QOB, QOU, HOM and CHOM breakers only. Other ampere 1p breakers, and all 2-pole and 3-pole versions are already high magnetic as standard. (Breakers with suffix GFI, AFI, CAFI, or DF are not available as high magnetic).


In a different FAQ they say:
"Because drives produce high level of leakage current, and depending of the sensibility of the breaker, tripping can occur.
At the start up of the drive, the capacitor bank is charging and we see the peak of leakage current. This peak is higher when there is more than one drive after the breaker.
Also, it's dependant on many installation parameters such as motor cable type, motor cable length, switching frequency, motor, ground connection.
To avoid the random tripping of breaker due to earth leakage it is recommended to use GFCI called full immunized type A "SI" which is reinforced against high frequency leakage current."
Click to expand...

So how much do those cost, I know an EPD breaker is typically much more then a standard GFCI breaker.
 
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