Tim, were the kits easy to get from the supplier?
73, Dan
On Mon, Nov 11, 2024 at 9:35 PM Tim Duffy <k3lr@k3lr.com> wrote:
> I have had good luck with Trane and American Standard HVAC units. Both
> required additional RFI kits. Once installed - dead quiet on the HF bands
>
> 73
> Tim K3LR
>
> -----Original Message-----
> From: RFI [mailto:rfi-bounces+k3lr=k3lr.com@contesting.com] On Behalf Of
> Dan K2YWE
> Sent: Monday, November 11, 2024 9:27 PM
> To: Rfi List
> Subject: Re: [RFI] HVAC
>
> Tnx fir the good info so far. Does anyone have experience with recent
> Bryant units?
>
> 73, Dan
>
> On Mon, Nov 11, 2024, 7:47 PM Steve Dyer W1SRD via RFI <rfi@contesting.com
> >
> wrote:
>
> > I think the take away is variable speed motors are not "evil". Properly
> > engineered (like anything else) they bring a ton of benefits.
> > My 11 year old Bryant Evolution Extreme heat pump is RFI silent. It has
> > a variable speed compressor in the outdoor unit and PCM blower in the
> > indoor unit. Really high quality stuff and silent in the audio range as
> > well. One of the most energy efficient air-source heat pumps made.
> > 73,
> > Steve
> > W1SRD
> >
> >
> >
> > On 11/11/2024 1:14 PM, Jim Brown wrote:
> > > Almost 30 years, Neil Muncy, W3WJE, (the Pin One Guy), showed me and
> > > an pro audio RFI colleague an in-house engineering report from a mfr
> > > of large variable speed drives. They were having problems with RFI
> > > from the drives screwing up the control circuitry from those drives,
> > > and identified the wiring between controller drive as a principal
> > > mechanism. The common thread was that the controllers and motors were
> > > widely separated.
> > >
> > > We were interested because RFI from drives running elevator motors was
> > > getting into microphone circuits in large sound systems. A system Neil
> > > was working on was at large performing arts center in NJ.
> > >
> > > A few years later, at a church in Dayton where I was inspecting a
> > > sound system I'd designed, I ran into an EE who specialized in EMC. We
> > > got to talking, and the conversation turned to variable speed drives
> > > in large installations. He volunteered that interconnecting wiring was
> > > the culprit, and we agreed that all of the current-carrying conductors
> > > had to be twisted pairs, which was the same solution Neil found.
> > > Obviously, making the controller and motor a single integrated package
> > > is also a great solution for smaller systems.
> > >
> > > 73, Jim K9YC
> > >
> > >
> > > On 11/11/2024 12:12 PM, Gary Johnson via RFI wrote:
> > >> I wanted to mention one other good strategy that these new
> > >> adjustable-speed drives are using: For most of the motors, they
> > >> integrate all the power electronics right into the motor assembly,
> > >> thus eliminating wires on the output side where the commutating
> > >> waveforms and high circulating currents are present. Then they are
> > >> applying proper RFI suppression to the incoming AC lines, again built
> > >> right into the motor assembly. So the potential antenna lengths are
> > >> greatly reduced and I’m seeing how effective this strategy actually
> > >> is. The only motor without this approach is the big compressor, and
> > >> that has a HUGE filter network nearby and also twisted wires to the
> > >> motor, all inside a steel enclosure. Carrier was not being cheap or
> > >> sloppy, and it shows.
> > >
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> >
> >
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