[RFI] Swimming Pool Pump RFI

[Steve Dyer W1SRD]

I have a Bryant/Carrier heat pump with a variable speed compressor. They 
sell a filter unit that installs on the outdoor unit and it works 
perfectly. I can't hear anything when it's running. Plus it is super 
quiet acoustically.
In fact every fan motor in the system is ECM and it's all RF quiet.
It is possible to have quiet variable speed gear and get the savings 
from this tech.
It's run for 7 years now without a hiccup.
I can get the model number if anyone is interested.
73,
Steve
W1SRD
> Top quality Pentair VS pool pumps generate huge RFI. Not just cheap Chinese. We have two at VP5M. The only way to bring it down to acceptable levels is the “brute force” line filter as close as possible to the pump. We use Schaffner filters in the amp rating of the motor. Mouser sells them about $40 each depending on amperage.
> Let your installer buy and install if they will. You’ll be amazed at the reduction in RFI if properly installed and grounded. You’ll also be amazed at how much electricity well programmed VS pumps save. That’s critical for us with island power at $.45/KwH!!
> 73,
> Jim K4QPL VP5M
>
> Sent from my iPhone
>
>> On Jun 25, 2020, at 9:50 PM, Jim Brown <jim at audiosystemsgroup.com> wrote:
>>
>>> On 6/25/2020 5:18 PM, Jim McCook wrote:
>>> No doubt it's a DC motor with a crummy Chinese switching power supply.
>> Or a variable speed controller for the motor. There's an app note on my website about building contest scores by killing RX noise. It ran several years ago in NCJ. k9yc.com
>>
>> The first thing I would do is insist that the contractor and/mfr fix it. If you choose to try to fix it yourself, I'd start by winding 4-5 turns of every wire/cable connected to it through a #31 clamp-on. This means on the AC line side and on the motor side. And any control lines. These cables are transmitting antennas for the noise.
>>
>> Also, make certain that the path for current to that motor is a transmission line -- in other words, forward and return current flow in very close proximity, which confines the field to a very narrow region between the wires. Minimum, "zip cord;" twisted pair is 30 dB better.
>>
>> Also, I would be VERY, VERY cautious about working on this -- electrical safety can be a major factor. Several decades ago, a professional colleague was called in as an expert witness in a case where a preacher was electrocuted in the church's baptismal font while holding a microphone for the church's sound system (this was before the widespread use of wireless mics), and SOMETHING was not wired in conformance to electrical safety codes (the font or the sound system).
>>
>> 73, Jim K9YC
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