Re: motor run caps

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Nicholas Field by way of Terry Fritz <twftesla-at-qwest-dot-net>" <nick.field-at-hvfx.co.uk>

Hi Justin

I would suggest that unless you know for sure it only needs a start cap, use
a run type cap. A 'run' type cap will work fine in 'start' duty, the same
cannot be said of a 'start' cap in 'run' duty.....

FWIW I have a few old program timers that use 1/20 hp. sync motors, and they
all need a run cap.  They are 240V types and use 0.5µF run caps, by
extrapolation yours will probably need a cap in the region of 1µF.  Given
the variation between motors it may be best to adjust the value in small
steps (say 0.25µF) to determine the best value.

Safe Coiling
Nick
_______________
Nick Field, HVFX
www.hvfx.co.uk

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, September 30, 2002 6:48 PM
Subject: RE: motor run caps


> Original poster: "Mccauley, Daniel H by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com>
>
>
>
> Actually, it probably needs a motor START cap, not a motor run cap.
>
> Dan
>
>
>
> Hi All,
>
> I know this is a bit of topic but...(it is for my coil through)..
>
> On the weekend I found an old (and small) synchronous motor (1500rpm).
> It had four wires.  The red and green were soldered together, the black
> and white were separate.
>
> I guess that this motor needs a motor run cap.  Does anyone have a
> formula to work out the size of the cap required?
>
> The specs on the motor are
>
> 1500rpm
> 115 vac
> 50hz
> 0.02 hp
>
> I have emailed the manufacturer but they are a little slow to respond.
> The motor looks quite old.
>
> Any help appreciated.
>
>
> Regards
>
> Justin.
>
>
>
>
>
>
>