Re: Cap Start Motor

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

Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net> 


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, May 08, 2004 9:52 AM
Subject: Re: Cap Start Motor


 > Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net>
 >
 > Hi Jim,
 >
 > The motor was advertised as a cap start.  In fact, I have seen no cap run
 > motors on ebay in the 1/3 and lower HP range.

While they may not be on ebay, there are hundreds of these PSC motors in
things like A/C blowers, etc. Check the Grainger catalog for instance.

We used to buy these motors (roughly a 1/4 HP) by the hundreds for use in
making very quiet fans (PSC motors run smoothly and quietly, and can be
speed controlled with a variac).

  Yes, I have emailed Franklin
 > Electric and still waiting for a reply.

Try a fax or a phone call.  It often works better than an email.  Many
industrial companies really don't have the e-mail thing really dialed in.

   I do think I'm making progress
 > though, I now believe the WHITE wire is the common wire and should be
 > connected to LINE NEUTRAL.  This will in effect let the start winding be
 > separate from the main winding.
 >
 > My current theory is that the BROWN and WHITE wires connect to the main
 > winding, the internal RED and WHITE wires connect to the start winding,
and
 > the external BLACK and RED wires go to a start cap (143 uf on the name
 > plate).  BROWN, being hot, goes thru the SWITCH to the external BLACK wire
 > and to the cap.  The external RED wire, coming from the other side of the
 > cap returns, goes thru the switch, and connects to the internal RED wire
 > connected to the start winding.
 >
 > I hooked it up this way and the motor runs.  The motor quickly got warm as
I
 > think the start switch is defective.  The BLACK path thru the switch was
 > open all the time and it was clear nothing would ever work that way so I
 > jumpered it.  The RED path thru the switch never opens (like a good start
 > switch should) so the start winding is never disconnected hence the
 > overheating.

You can hook an ohmmeter up to the "switch" and spin the motor  with an
electric drill to see if it works.

 >
 > Disaster then happened.  My power cord (plugged into the variac) to motor
 > connection accidently shorted with the variac dial set to zero and the
 > variac when up in smoke.  I took the variac apart (one of these "NEW RED"
 > ones bought on ebay from Canada and made in China) and found that the
input
 > LINE NEUTRAL and LINE HOT were wired up backwards.  The circuit breaker
was
 > in the NEUTRAL path and when the setting was zero, both of the LINE
NEUTRAL
 > and LINE HOT outputs were HOT.  The short must have been to SAFETY GROUND
 > and the circuit breaker did not protect.   So, we all need to beware!!!