"James Sweet" wrote in message
news:0Shbe.4340$Nc.2409@trnddc05...
"Sam Goldwasser" wrote in message
...
"Asimov" writes:
" bravely wrote to "All" (24 Apr 05 21:20:34)
--- on the heady topic of "AC shaded pole single phase induction
pole
motor"
an From:
an Xref: aeinews sci.electronics.repair:46513
an Sir/Madam
an i have a dayton a.c. shaded pole single phase motor with
1/150HP,
an 3000
an RPM, 230 V, 60 Hz frequency and Full Load Amps
an 0.24 . I want to control the torque of this motor through
program.For
an that i have feedback from motor is current to the motor . I want
to
an control the torque use this current as feedback.for that I need a
an equation connecting torque and the current.
RPM of this motor type is dependant on frequency. Altering the voltage
will only give approximately 10% practical change in torque.
While most induction motors are run at nearly constant speed, for shaded
pole motors with a light load like a fan, the torque and thus speed can
vary
from near zero to almost synchronous speed based on input voltage. I
use
a
Variac to control my window fan. It works very well.
As will a simple light dimmer in most cases, though some don't like
driving
inductive loads. Speed controllers for shaded pole motors are widely
available and they're nothing more than a triac dimmer circuit.
I tried this once with as a mod to drying fans in a photographic print
processor
and there was a cyclic revving / slowing effect rather than constant
RPM.