Richard (Rick) Karlquist wrote:
>
>
> The biggest user caused problem with these things is insufficient
> wiring. If the wiring is marginal, the breaker may or may not
> trip depending on temperature and other conditions. The motor
> draws 20A @ 120V. That is a 6 ohm load. The round trip resistance
> of wiring back to your *service entrance* should be only 5% to at
> most 10% of this. For 10%, this works out to 200 ft of 12 AWG wire.
> And that's marginal. I use doubled up 10 AWG wiring for mine, and
> it just barely starts on hot days. I believe it is well known
> that insufficient voltage on motors is bad for them. Of course
> leaving the power applied to a motor with a dead starting cap
> can't be good either. Starting caps go out all the time. I
> used to have a pool pump motor that went through caps at the rate
> of a new one every year.
>
>
A bit too much resistance leads to the motor starting slowly, so the
speed switch doesn't turn off the start capacitor as quickly as it
normally would. Those capacitors are pretty lossy, and they are a price
sensitive item so they are right at the ragged edge.
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