Re: Sewing machine motor - reversing direction

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

Original poster: "Sean Taylor by way of Terry Fritz <twftesla-at-qwest-dot-net>" <taylorss-at-rose-hulman.edu>

Unless your motor has a seperate series or shunt coil, and an armature coil,
reversing the connection to the brushes won't reverse the direction of the
motor, since the power to the motor is AC.  The current is reversing
direction constantly - it switches every ~8.33 mSec.  If the motor does have
a second winding in it, then reversing the connection on one of the windings
will reverse the direction of the motor, since you are then reversing the
relative magnetic fields, but that would most likely involve taking the
motor apart.  I also doubt that a sewing machine motor is that complicated.
It probably just has permanent magnets on the outside.

If you want to try reversing the wires, you wont harm the motor, but be
careful, one of the wires from an outlet is 120 VAC with respect to ground,
while the other is at ground potential. The motor case might be hooked to
the neutral wire, in which case if you reverse them, the case of the motor
could be 120 VAC from ground!  Hope that helps!

----------------------
Sean Taylor
The Geek Group
G-2 #1204
Because the geek shall inherit the Earth! (c)
www.thegeekgroup-dot-org



----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, February 16, 2002 10:07 PM
Subject: Sewing machine motor - reversing direction


> Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>
>
> Hi:
>
> Has someone found uses for common sewing machine motors in
> Tesla coiling?
>
> But specifically, I would like to know how to reverse the
> rotation direction of one that I have here. I plan to use it
> to drive a static machine, but observed that it is rotating
> in the wrong direction for my plans. I didn't open yet one
> that I have here to see what is inside. The motor is powered
> by two wires, at 110 V AC, one of them passing through a speed
> control device that appears to be just a pressure-sensitive carbon
> resistor.
>
> I imagine that it's just a question of reversing the connections
> of the brushes, but would like to know if only this works.
>
> Antonio Carlos M. de Queiroz
>
>
>
>
>