Hi Gary,
I suspect they learned this trick from the grow light makers... Of late,
a lot of them are putting the inverter in a metal light fixture housing
at the LEDs, so the only thing to filter is the AC cord... Some things
are getting better.
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources
On 11/11/24 12:12, 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.
Gary NA6O
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