Synchronous Motors

To: tesla-at-pupman-dot-com
Subject: Synchronous Motors
From: Tesla List <mod1-at-pupman-dot-com>
Date: Wed, 1 Oct 1997 10:07:42 -0600 (MDT)
Approved: mod1-at-poodle.pupman-dot-com

---------- Forwarded message ----------
Date: Tue, 30 Sep 1997 23:44:00 -0700
From: Bert Hickman <bert.hickman-at-aquila-dot-com>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Synchronous Motors

Group, 

Awhile back, Ed Phillips indicated that some of the older Teletype
motors were actually synchronous motors. I've just confirmed this at the
latest Hamfest, where I found a 3600 RPM, 1/12 HP, synchronous capacitor
motor for only $5.00. It's marked as Teletype part number 159739, and is
rated at 115 VAC at 2.7A. The seller indicated that it had been removed
from an ASR-33 that he had dismantled for parts. 

Physically the motor is about 6" long by 3.5" diameter, appears to have
a 5/16" diameter shaft, comes with a phase-shifting capacitor, and IS
truly synchronous. When powered from a variac under increasing voltage,
it will suddenly spin up, and at about 75 volts will "lock in" to
synchronous operation. The lock is very pronounced, and once locked-in,
varying the input voltage has little effect. 

Thanks, Ed, for the tip!

-- Bert H --