Pentair pool pump nuisance GFI trips solved with toroid core

D

ddbear

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Designer
Just wanted to report back that after 2 years, zero nuisance trips with the solution I described here:

Pentair VSF pool pump trips GFI (continued)

I came across this previous thread (now closed for replies) and would like to continue the discussion, https://forums.mikeholt.com/threads/pentair-pool-pump-gfci-trips.136417/page-7 I am having the same problem with my Pentair IntelliFlo3 VSF pump, which is a new model just recently introduced...
forums.mikeholt.com
(I'm posting a new thread because the original one is closed for replies)
 
ddbear said:
The GFI works perfectly fine. It tests good.

Is there a reason for your skepticism? Bottom line is that my solution works, and it works over the long term.
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Toroid cores are frequency specific, in the very high range. Seems an improbable match without scoping load noise first.

Would be more believable if you removed the toroid, and GFCI tripped.

I’m also skeptical of GFCI’s, not you.
 
ramsy said:
Toroid cores are frequency specific, in the very high range. Seems an improbable match without scoping load noise first.

Would be more believable if you removed the toroid, and GFCI tripped.

I’m also skeptical of GFCI’s, not you.
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First of all, it works, 100%. I had nuisance tripping every few hours to ever few days prior to the installation of the core. Also, a smaller core designed for audio cables etc. did not work. I tried this specific core based on a post I found by someone knowledgeable in electrical engineering and then suddenly it worked. That person hypothesized about the cause of the pool motor nuisance tripping but did not try his solution on his own. I took the theory and applied it and now I'm reporting back. If you dig the internet enough his post is on one of the electrical forums.
 
ramsy said:
Toroid cores are frequency specific, in the very high range. Seems an improbable match without scoping load noise first.

Would be more believable if you removed the toroid, and GFCI tripped.

I’m also skeptical of GFCI’s, not you.
Click to expand...
VFD's would cause capacitive leakage because of the high carrier frequency they use. Seems logical the core may very likely cancel out some the capacitive effects.
 
kwired said:
VFD's would cause capacitive leakage because of the high carrier frequency they use. Seems logical the core may very likely cancel out some the capacitive effects.
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Must defer to VFD gurus, but agree harmonic loads defeat GFCI garbage.
 
ramsy said:
Must defer to VFD gurus, but agree harmonic loads defeat GFCI garbage.
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I don't think harmonics is the problem, the high frequency switching (which also does lead to increased harmonics) is the problem.

Frequency is a variable in determining the reactance value of a capacitor, keep everything else the same but increase frequency, and you have lower overall impedance from that capacitor which means more capacitive leakage from the circuit conductors.
 
Knuckle Dragger said:
How would you size up the core to the motor, of that's what you did? Is there a chart?
Just trying to get educated.
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ptonsparky said:
And how many wraps? Is there a theory to it?
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Something tells me you can probably over do it and have less problems than if you under do it? Would just be an inductive choke if you over do it.

location in the run likely more critical? Placing the coil at the GFCI probably doesn't eliminate as much leakage over the length of the circuit as placing it near the source of the high switching frequency would?
 
retirede said:
How do you do that in the field when the source is a listed, integral VFD/motor assembly?
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With filtering components in the supply circuit, like maybe the torrid core the OP used? Not exactly a direct treatment to the source but locating it close to the source minimizes the effects on the supply circuit.
 
Pentair in the past has specified the use of Siemens GFCI breakers to protect their VFD pool pumps as they don't trip like the other brands do. Now they have a Pentair GFCI breaker, but pretty sure that it is a rebranded Siemens breaker.
Unofficial sources have told me that these breaker do have a filter to remove the high frequency tripping issue. However I have not been able to confirm that.
 
kwired said:
location in the run likely more critical? Placing the coil at the GFCI probably doesn't eliminate as much leakage over the length of the circuit as placing it near the source of the high switching frequency would?
Click to expand...

I placed the ferrite core inside the subpanel where the SquareD GFI breaker is, which is about 50 ft away from the Pentair pump location.

I previously also solved it by temporarily trying a Siemens GFI breaker instead, but I went back to the SquareD with this ferrite core so that I could have the subpanel type that I wanted.
 
don_resqcapt19 said:
Pentair in the past has specified the use of Siemens GFCI breakers to protect their VFD pool pumps as they don't trip like the other brands do. Now they have a Pentair GFCI breaker, but pretty sure that it is a rebranded Siemens breaker.
Unofficial sources have told me that these breaker do have a filter to remove the high frequency tripping issue. However I have not been able to confirm that.
Click to expand...
If there is capacitive leakage due to this high frequency I don't see what any filter in the breaker would do to stop the leakage, you would need to filter out the high frequency before it hits the branch conductors to keep the capacitive leakage effects from occurring in the first place.

ddbear said:
I placed the ferrite core inside the subpanel where the SquareD GFI breaker is, which is about 50 ft away from the Pentair pump location.
Click to expand...
What I just said above would apply here as well.

There has to be more than capacitive leakage going on here?

I have had to deal with this problem A time or two with clothes washers with electronic drive motors and GFCI tripping issues. Temporarily disconnecting the equipment grounding conductor stops the tripping issues. There is no ground for the leakage to travel to. One these machines I encountered had a "grounding switch" that closed the equipment ground to the motor frame if you took the back cover off the appliance. That switch had broken mounting tab and therefore was hanging there in a closed position. Any time the machine attempted to start the motor the GFCI tripped. That tells me the manufacturer knows there is leakage coming from that motor that will trip the GFCI. They put the switch in there to isolate it so it won't trip the GFCI. But it is closed and will effectively have GFCI protection if someone removes the back cover of the appliance.

I guess I am not seeing how they can put something in the GFCI to filter this out and not compromise the protection some from what the 4-6mA listing standards require. And this is complicated by more stuff in recent years that isn't compatible with GFCI's along with expanded GFCI requirements that some these items end up connected to.
 
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