Remediation of line noise from well pump

jrfuda

Active Member
Haven't posted in  while...
 
I have five ceiling fans controlled by Lutron MA‑LFQHW Fan controls which have worked flawlessly for over 3 years. These are not home automation lighting controllers, however, they use some sort of PLC to control fan speed and light dimming. They are great for my purposes, especially since I did not want to run new wire for independant fan speed and dimming control in my 113 year old walls.
 
About 3 months ago, one of them started acting up. It was at the same time that I installed and new 220V 25A circuit for my Franklin 35SDQP-3.0HP-N4 QuickPAK (controller, pump and motor package) for my irrigation system. The fan controller in question is the only thing on its circuit and about 5' from the circuit breaker box. The pump controller is about 125 feet from the breaker box on a 220V 25A circuit and connected with 8 AWG stranded copper. The pump motor is another 65 feet down in the earth.
 
The controller for the Franklin pump is a constant pressure type and also converts power to 3-phase. This is supposed to be able to get 5HP performance out of a 3HP motor. As far as I can tell it works flawlessly as it has no trouble keeping up 45 GPM at 68 PSI for my sprinkler system (at around 55 PSI by the time it reaches the valves and regulated to 45 or 30 PSI depending on the zone... the regulators need 15 PSI overhead to do their job). The constant pressure feature varies the speed of the pump based on the demand and ensures it stays right at 68 instead of cycling like a traditional controller.
 
I determined it was the pump controller as switching of its breaker or pulling the ON/OFF switch at the well site makes the problem go away.
 
I did some research online and it appears that several HAM radio operators have noise issues with these systems as well. I did not find much reference to interference with PLC except for someone saying their pool pump caused issues, but could not find a solution.
 
I replaced the fan controller with a new one and it made no difference.
 
I contacted Franklin today via email to see if they have any ideas.
 
I tried placing a ferrite choke on the same phase as the problematic fan controller  (fit perfectly over the 8AWG wire in the box in the well) and it helped a little. The fan controller works now as long as the pump is actively pumping. I only had one choke at the time and am not sure if putting one on the other phase would matter anyway. This was a Hail Mary as I didn't think it would do anything.
 
My guess as to why the other 4 fan controller were not affected is that all the additional loads and length of cable on each of their circuits is attenuating the interference .
 
So, what do y'all think is the best way to clean the noise from the line at the source? I thought about a pair of ACT AF300 low pass filters, however, they're only rated at 20A and they're about $60 each. I have several noise filters for car audio, however, they're for 12VDC. I can't seem to find an all in one solution for 220V... I thought one of those old whole house x10 filter/couplers like Leviton 6284 installed by the switchbox at the well site might work, but I think they're no longer made. Could I gut a couple of plug-in filters, wire them in line and place them in a new box? Is there a DIY-friendly noise filter schematic that someone with limited soldering skills could pull off?
 
This appears to be the manual for the motor controller:
 
http://www.franklin-electric.com/media/documents/225417101%20M1560%20SD%20Manual%205.13%20WEB.pdf
 
Under accessories (page 44) it lists both an output and an input filter "to help eliminate interference".  Your email to the manufacturer will probably get a recommendation of one or both of those.  Since the ferrite core helped I would try running both leads through a larger ferrite core.  Multiple turns will help too.  Putting them over one lead is usually not as effective as running both leads through the same core.  You could try the same thing on the output leads (all three leads through one core). 
 
I read through the maual and never looked at the accessories page. Maybe that will be the fix. I did not find the part number searching online.

Would placing several chokes in line have the same effect as multiple windings? I ask because the 8 awg to the pump controller can take only a straight run and the 14 awg on the fan circuit can barely make a single loop through the choke.
 
Several cores on the wire will be more effective than one but not as much as multiple turns. 
 
Your term "single loop" is a problem...  What counts is the number of passes through the center.  I am guessing your "single loop" passes through the center twice, making it two turns.  It's a common mistake to count turns on the outside of the core.
 
Sounds like you need bigger cores.
 
The tech from Franklin replied back that I need to have someone check and ensure my electrical system ground is 25 ohms or less. There are no residential electricians around here that do that, and equipment to DIY is at least $200. Typically, if someone has issues, they just add a second grounding rod 6 feet away and bind them together, which is acceptable by code in place of a test. I have no idea what the resistence of my ground is and have never had any issues, but I may just gamble $15 on a ground rod and try it. The tech also said I need to keep the wires a minimum of 8" from all other wires in the house during paralell runs. I don't see how that is possible since they all terminate in the same breaker box, so the last 4 feet or so of every circuit in the house is parallel with another. I ordered a handful of ferrite cores of various sizes and will try them on all three wires (incl ground) as well coming from the pump controller/vfd to see if they help. I need to double-check the input/output wires on the controller/vfd as well to make sure there is adequate seperation as well.
 
I added a second 8' ground rod, bound it to the first and relocated the fusible switch pull box, which was mounted only a few inches from the pump controller/VFD, to a new location about 18" away. The problem appears to be solved. I'm not sure which of the two solved the problem, but it's gone and I'm happy.
 
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