[RFI] RFI from variable speed swimming pool pumps

[James Jordan]

Thanks, guys, for all the useful info. Taking Jim's comment "In general,
variable speed motors should be assumed to be noisy until proven otherwise"
I'm going to have to plan for that before doing the changeout down in Turks
& Caicos. We don't have quick Mouser, Gigaparts or Amazon deliveries down
there! I'll order the Variable Speed Pentair pump, separate the pump and
motor if feasible, otherwise use test tank to keep pump from running dry,
connect temporarily and listen and look for RFI on Panadapter here at home
QTH. If there's enough built-in suppression, great. Otherwise I'm looking
at line filters, and while there are some cheaper Chinese ones offered on
eBay, the Schaffner FN2070-10-06 at <$50 on Amazon looks like something
that should make a difference. Will handle 10A which at 240V is well over
the draw of a 1.5HP motor. Also maybe take a large #31 ferrite as Jim
suggested. Other comments or suggestions?
73,
Jim, K4QPL; VP5M


On Sun, Jul 1, 2018 at 1:18 AM, Jim Brown <jim at audiosystemsgroup.com> wrote:

> On 6/30/2018 9:49 PM, Randy Standke wrote:
>
>> In addition, some type of filtering on the ground wire may also be needed
>> because the line filters don't filter the ground wire.  A large clamp on
>> ferrite over all the power wires will also filter the ground.
>>
>
> WRONG -- sort of. The solution is multiple turns of the line cable wound
> through a large #31 ferrite core, NOT the ground wire only. In general,
> commercial line filters are effective ONLY if they are integral to the
> equipment, so that they are properly bonded to the shielding enclosure of
> the equipment. Simply clamping a ferrite onto the cable (a single turn)
> works only at VHF, and multiple clamps will be required.
>
> In general, variable speed motors should be assumed to be noisy until
> proven otherwise.
>
> 73, Jim K9YC
>
>
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