Yeah, the amount of RF emitted is actually very small so long as the device
is connected only to a "dummy load". If there is good bonding and RF is
blocked at the source with a brute force filter to keep it off the power
and control lines, and your radio antenna has some reasonable distance or
orientation from both, RFI from VS Drives is usually negligible. A low pass
or band pass filter on your radio may also help. Using a transistor AM
radio I was picking up VS drive pool pump hash near every AC circuit in the
house (read "transmitting antennas") until I put the Schaffner filter on it
at the drive. RFI gone. Because of their efficiency variable speed drives
are not only here now but ARE the future. A few low end HVAC manufacturers
may keep making single speed, but I am very familiar with one HVAC company
which sells about two variable speeds for one cheap fixed speed one, That
ratio is sure to increase until the manufacturers quit making single
speeds. Price difference is recovered in a year or so of electricity
saving. Neither the FCC nor UL is going to make the manufacturers make
them 100% RFI free so we must adapt. Think about how hams learned to kill
the ignition noise from that '54 Chevy, or ITV from the early models of the
tube! I never hear my Carrier Infinity system and we're in a very quiet
semi-rural subdivision.
73,
Jim K4QPL
On Mon, Jul 25, 2022 at 3:06 PM Jim Miller <jim@jtmiller.com> wrote:
> FYI my WaterFurnace geothermal system has both variable speed motors
> throughout and is RFI quiet.
>
> https://www.waterfurnace.com/residential/
>
> jim ab3cv
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