[RFI] Multi-Stage High Efficiency Air Conditioner Units

[K9MA]

Ferrite common mode chokes are very unlikely to have adverse effects on 
the electronics, unlike bypass capacitors. (Slow rise times, oscillating 
op amps, etc.) And they often ARE effective at reducing RFI.

That said, I have one of those cheap Bryant furnaces with variable speed 
blowers, and I've never heard any RFI from it. Nor does 1500 W into a 
shunt fed tower on 80 and 160 forty feet away affect it. Unlike the 
water heater, which I have to reset after every 160 contest, or I'm in 
big trouble.

73,
Scott K9MA


On 2/8/2020 07:25, AA5CT via RFI wrote:
>   re: " What happened to RF chokes and bypass capacitors, which when
> the correct component values and specifications are used (value,
> current handling and voltage rating), will work better and cost much
> less? "
>
>
> Fine, if you are the OEM (and can implement those at board level),
> not so fine on a new installation where there is a warranty in effect.
>
> Using the ferrites a service tech can see the "minimal intrusion" the
> ferrites make into the circuitry of the unit (whether on the AC line side
> or the thermostat side.) Getting in there to add circuit components to
> a control board is a whole 'nother thing.
>
>
> de AA5CT
>
> .
> .
>
>       On Saturday, February 8, 2020, 06:16:12 AM CST, Rob Atkinson <ranchorobbo at gmail.com> wrote:
>   
>   First, there's nothing wrong with American Standard as far as I know,
> which is a premium brand manufactured in Texas by Ingersol Rand.
>
> Forced air A/C in the home, almost always uses the same air blower
> motor that's used by the furnace.  If that's the variable speed
> component, you can solve everything by getting an AC motor.  The
> variable DC motors are used by people who obsess over a relatively
> minor improvement in efficiency.
>
> Why do hams mindlessly use ferrite on everything, including lines that
> only have DC on them?  What happened to RF chokes and bypass
> capacitors, which when the correct component values and specifications
> are used (value, current handling and voltage rating), will work
> better and cost much less?
>
> 73
> Rob
> K5UJ
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-- 
Scott  K9MA

k9ma at sdellington.us