Pentair pool pump nuisance GFI trips solved with toroid core

[ELA]

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.

It is possible for most electronics to be upset/reset/trip due to ElectroMagnetic Interference such as that generated by high frequency interference.
Many products do not take Electromagnetic Compatibility into consideration unless required to do so my being held to more stringent EMC standards.

In the past I had performed EMC compatibility testing and it was easy to upset/reset/trip electronic devices if they had not been designed and tested to meet a higher level of EMI. Generally devices designed to be sold in Europe can withstand higher levels of EMI, when tested to EMC standards required for "CE" marking.

High frequency currents enter the circuitry and find alternate pathways to upset microcontrollers etc. In the case of the GFCI it may have little to do with capacitive leakage of the external conductors when subjected to high frequency interference.

Ferrite cores are most often used when the offending frequencies are higher and to combat Radiated EMI. For conducted EMI such as with the drive an EMI filter is generally more effective to attenuate the lower frequencies. If you get lucky and the ferrite core works it is of course much less expensive than high current EMI filters designed with large inductors.
The impedance that the Ferrite inserts into the conductors increases with the square of the number of turns used.

 

[JWMap]

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)

I wanted to share a recent experience with this. A year ago I had an Eaton GFCI installed on my single speed 2HP Century pool pump motor going through a mechanical timer (Intermatic T100). It worked fine for a year and begin to trip about once a week on a high level 30ma+ ground fault. The Eaton GFCI has an LED diagnostic that identifies this fault. It would sometimes trip at the time the pump shut off but never when it started. I was never able to cause the trip by manually shutting it off. I assumed it was the old motor that developed a ground fault and talked to the pool tech about replacing it with a Pentair Intelflo3 VSF. I had read this thread and aware It might introduce a new problem with the Pentair on an Eaton GFCI rather than a Siemens GFCI. Adding a Siemens GFCI meant adding a separate subpanel since code doesn't allow me to mix that GFCI in my panel. So I thought to give it a go with the existing Eaton GFCI. WIth a retrofit, the 240VAC for the pump came off the existing Intermatic terminals like the old pump and bypassed the timer since the new pump timings are controlled through wifi. And sure enough, the new Pentair pump would trip 2-3 times per day from the start! A new Siemens subpanel was quoted at $3K by an electrician and 50AMP service was even worse to hook up the heater, spa, sweeper to one subpanel.., so I was considering trying this toroid. When I opened the intermatic, I noticed the terminals were slightly lose... Not exactly 100% tight. Perhaps a quarter of a turn on the power terminals coming from the GFCI. The Pentair has run now for one week without tripping once on the Eaton GFCI without doing anything but tightening terminals... I am speculating that the pump turning off had a back EMF creating a transient type imbalance through the loose connection. And this imbalance was causing the Eaton to trip. Somewhat like the spark you get when you pull the plug from a running vacuum cleaner. However, it will need more time to see if it keeps running. But the lesson here, especially on retrofitting pumps like this, is make sure the existing connections are solid and tight if using any type of old terminal or other connectionist that loosen with vibration or over time. I am surprised that just a slight turn of a screwdriver is all it took and had such a significant impact on the GFCI to work properly.

 

[ptonsparky]

It's hard to argue with success!

 

[kwired]

I wanted to share a recent experience with this. A year ago I had an Eaton GFCI installed on my single speed 2HP Century pool pump motor going through a mechanical timer (Intermatic T100). It worked fine for a year and begin to trip about once a week on a high level 30ma+ ground fault. The Eaton GFCI has an LED diagnostic that identifies this fault. It would sometimes trip at the time the pump shut off but never when it started. I was never able to cause the trip by manually shutting it off. I assumed it was the old motor that developed a ground fault and talked to the pool tech about replacing it with a Pentair Intelflo3 VSF. I had read this thread and aware It might introduce a new problem with the Pentair on an Eaton GFCI rather than a Siemens GFCI. Adding a Siemens GFCI meant adding a separate subpanel since code doesn't allow me to mix that GFCI in my panel. So I thought to give it a go with the existing Eaton GFCI. WIth a retrofit, the 240VAC for the pump came off the existing Intermatic terminals like the old pump and bypassed the timer since the new pump timings are controlled through wifi. And sure enough, the new Pentair pump would trip 2-3 times per day from the start! A new Siemens subpanel was quoted at $3K by an electrician and 50AMP service was even worse to hook up the heater, spa, sweeper to one subpanel.., so I was considering trying this toroid. When I opened the intermatic, I noticed the terminals were slightly lose... Not exactly 100% tight. Perhaps a quarter of a turn on the power terminals coming from the GFCI. The Pentair has run now for one week without tripping once on the Eaton GFCI without doing anything but tightening terminals... I am speculating that the pump turning off had a back EMF creating a transient type imbalance through the loose connection. And this imbalance was causing the Eaton to trip. Somewhat like the spark you get when you pull the plug from a running vacuum cleaner. However, it will need more time to see if it keeps running. But the lesson here, especially on retrofitting pumps like this, is make sure the existing connections are solid and tight if using any type of old terminal or other connectionist that loosen with vibration or over time. I am surprised that just a slight turn of a screwdriver is all it took and had such a significant impact on the GFCI to work properly.

"inductive kickback" has been known to cause GFCI tripping in many applications for a very long time.

 

[ptonsparky]

Typically those loose connections would show up in obvious overheated terminations.

 

[JWMap]

I wanted to share a recent experience with this. A year ago I had an Eaton GFCI installed on my single speed 2HP Century pool pump motor going through a mechanical timer (Intermatic T100). It worked fine for a year and begin to trip about once a week on a high level 30ma+ ground fault. The Eaton GFCI has an LED diagnostic that identifies this fault. It would sometimes trip at the time the pump shut off but never when it started. I was never able to cause the trip by manually shutting it off. I assumed it was the old motor that developed a ground fault and talked to the pool tech about replacing it with a Pentair Intelflo3 VSF. I had read this thread and aware It might introduce a new problem with the Pentair on an Eaton GFCI rather than a Siemens GFCI. Adding a Siemens GFCI meant adding a separate subpanel since code doesn't allow me to mix that GFCI in my panel. So I thought to give it a go with the existing Eaton GFCI. WIth a retrofit, the 240VAC for the pump came off the existing Intermatic terminals like the old pump and bypassed the timer since the new pump timings are controlled through wifi. And sure enough, the new Pentair pump would trip 2-3 times per day from the start! A new Siemens subpanel was quoted at $3K by an electrician and 50AMP service was even worse to hook up the heater, spa, sweeper to one subpanel.., so I was considering trying this toroid. When I opened the intermatic, I noticed the terminals were slightly lose... Not exactly 100% tight. Perhaps a quarter of a turn on the power terminals coming from the GFCI. The Pentair has run now for one week without tripping once on the Eaton GFCI without doing anything but tightening terminals... I am speculating that the pump turning off had a back EMF creating a transient type imbalance through the loose connection. And this imbalance was causing the Eaton to trip. Somewhat like the spark you get when you pull the plug from a running vacuum cleaner. However, it will need more time to see if it keeps running. But the lesson here, especially on retrofitting pumps like this, is make sure the existing connections are solid and tight if using any type of old terminal or other connectionist that loosen with vibration or over time. I am surprised that just a slight turn of a screwdriver is all it took and had such a significant impact on the GFCI to work properly

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)

I had one other question for anyone reading this. DId anyone notice consistency WHEN the trips occurred for the Pentair Iintellifo3? . For me, I noticed there was consistency when the pump would trip. It was always when I dropped speed of the motor based on the app program.. It never happened when I started it (0-90%speed) or even stopped it completely (60%-0%). For me, the trips would occur when the speed dropped from 80% to 60% which was programmed to occur late in the day. The power drop for the 1.5HP motor goes from 875W to 378W and made me wonder if a workaround might be to ramp down speed (i.e. 80%, 70%, 60%) opposed to a sudden speed drop where the induction remains and its trying to revert the PWM to a new lower frequency. I never got trips when the motor completely shut off or when I went small increments down like 90% to 80% to 75%. The other consideration is if the motor is more susceptible to noise at lower speeds at 60% or below. In any case, with my experience in industrial control, we would always ramp down speeds for mechanical reasons opposed to sudden speed drops. Just a suggestion for anyone wanting to experiment with a workaround prior to wiring changes. Seems easy to schedule additional programs with the app to do a ramp down to lower speed.

 

[ptonsparky]

For a pump, I would think coast would be sufficient. Too short of ramp time is an issue.

 

[kwired]

For a pump, I would think coast would be sufficient. Too short of ramp time is an issue.

I agree, may not matter much with GFCI but too rapid of deceleration of any driven load can cause overvoltage on bus fault code on the drive itself. This is likely not much issue for most size/type of pumps in this discussion though. As the media flow probably doesn't have enough inertia to tend to keep the pump going for much at all after you take away driving torque of the motor.

 

[synchro]

Just a comment on the FT-240-43 toroid core that @ddbear mentioned that he was using in his earlier post:
The 240 designates that the O.D. of the toroid is 2.4 inches. The 43 designates the type of material used for the core.

The approximate frequency ranges where the materials numbered 43, 31, and 75 work best for common mode chokes are:

43 10 - 300 MHz
31 1-10 MHz
75 150 KHz - 30 MHz

More info is given at the link below.

And so depending on the spectrum of the conducted interference produced by a VFD or other source, and the susceptibility vs. frequency of a given GFCI to trip, one type of material may be work better than the others.

Ferrite Mix Selection - Palomar Engineers®

Ferrite Mix Selection Guidelines Quite often we are asked which mix is best for a certain application or frequency range and there is a lot of misinformation on the internet and elsewhere regarding the selection of proper mix for a given application. Material Types There are two basic ferrite...

palomar-engineers.com