Fw: [Boatanchors] rotor starting capacitor

[J. Forster]

> On Thu, 8 Jul 2004 10:35:28 +1000 "Brian Clarke"
> <brianclarke01 at optusnet.com.au> writes:
>
> > Another respondent to this group suggested using a pair of steering
> > diodes
> > around your pair of reversed dc capacitors. This is close to a good
> > solution.
> > Philips, in their book on diodes, published about 30 years ago,
> > suggested
> > putting a dc electrolytic capacitor inside a diode bridge. This way
> > the
> > capacitor
> > is always polarised correctly, you only need one capacitor, and you
> > can
> > probably afford 4 diodes. My only caveat would be to measure the
> > capacitance to be sure it's within cooee of the motor's requirement
> > before
> > re-installing the whole lot at the top of your tower. Measure the
> > capacitance
> > OUTSIDE the diode bridge, ie, the way the motor and the ac mains
> > will see
> > it.
> >
> > 73 de Brian, VK2GCE.

I would suggest some caution when making such a measurement. It should be made
under large signal conditions so that the effects of the diode drops can be
ignored. Many bridges, DMMs, and  'C' meters will give meaningless results.

-John