On Wed, 1 May 2013 15:44:06 -0400, "Wild_Bill"
wrote:

One possible reason for neither of the black leads showing any continuity to
any other wires could be the appliance was discarded for a reason.. maybe
the motor went bad years ago.

A 3uF motor cap would very likely be on a PSC type motor. The wiring scheme
for a PSC is similar to a center-tapped transformer.. 2 (nearly) identical
windings in series.

wire o--------------o--------------o wire


The center tap is a third wire, and the resistance readings from center to
each end would be close to identical, and combined, those readings would
equal the end-to-end resistance reading.

No manufacturer would use a black wire for an earth ground wire. Earth
ground is nearly always green, although sometimes green/yellow.

The white wire is common to the motor capacitor and the HV module, so I'd
expect that to be the neutral of 120VAC (located electrically at the center
of the 2 windings).
The grey wire likely goes to an end of one of the windings.

I'd suspect that one of the black wires was the hot side of 120VAC.
Since there's no continuity, then likely a break in the wire-to-winding
connection or an open winding.

PSC motors are frequently thermally protected, so a slim possibility could
be a bad (open) thermal protector. Trouble is, it may not be easy to find
it.

Those insulated splices may be Buchanan splice-caps.. very common in
consumer appliance wiring. They're very reliable when crimped properly with
the Buchanan crimper.. and the insulating caps just snap on over the splice.
Very consistent results if used conscientiously.


The box I pulled this out of looked Brand New. The plastic Fan blade, housing
and motor had no dust whatsoever. True that the HV charge might have reduced
that accumulation, but this was as new. I pondered the possibilities and also
thought that the motor might just be open from the black lead. Good reason to
toss it. But the schematic makes no sense. Unless it was incorrectly wired
from the factory. The white motor winding just begs for the AC line that
connects to the black lead.

I have yet to put it on the bench again to measure the start winding and see
what relationships show up.

Will report back what I find.

Thanks much for the chat!