Re: SRSG phase controller

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

Original poster: "Steve White by way of Terry Fritz <twftesla-at-uswest-dot-net>" <slwhite-at-zeus.ia-dot-net>

If I understand what you are saying, you do not switch in the phase control
circuit until the motor has spun up without the phase control circuit. If
this is so, don't you have a potential problem with the motor seeing an
abrupt phase shift in its power supply when you do switch in the phase
control circuit?

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, April 18, 2001 10:03 AM
Subject: RE: SRSG phase controller


> Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<jduva-at-baytechnologies-dot-net>
>
>   I've done something like that with my phase controller.  I have two
> switches, though.  One switch (dimmer) spins up the motor smoothly.  That
> dimmer is plugged into the phase control box, which houses an AC volt
meter,
> a surface mount fuse, and a toggle switch.  The control box is bolted
> directly onto a small variac and the cap bank hugs the side of the variac.
> The control box gets plugged into the 120V power source, the motor gets
spun
> up using the dimmer, then the toggle switch is thrown to connect the fuse,
> cap bank, and variac to the circuit.
>   When everything gets shut down, the phase control circuit is removed via
> the toggle switch before the motor power gets cut.  If I forget to switch
> off the control circuit, I get a mild self-braking from the 1/6 HP motor
> which usually blows my fuse in the control box or trips the protective
> circuitry in my motor.
> I don't have schematics with me, but I remember that I used John Freau's
> design for the phase control circuit and just added the toggle switch
before
> the fuse and caps.
>
> Hope that helps in some way!
> -Joe
>
> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Wednesday, April 18, 2001 8:10 AM
> To: tesla-at-pupman-dot-com
> Subject: SRSG phase controller
>
>
> Original poster: "Steve White by way of Terry Fritz <twftesla-at-uswest-dot-net>"
> <slwhite-at-zeus.ia-dot-net>
>
> I have been following the posts concerning the design of SRSG phase
> controllers. One of the major concerns, at least for larger motors,
appears
> to
> be the self-breaking action of the motor upon spin down. Could this not be
> prevented through the use of a double-pole switch to completely remove the
> phase control circuitry from the motor when it is turned off? One of the
> switch
> poles would break the circuit from the 120 volt power while the other
switch
> pole would simultaneously break the circuit from the phase controller to
the
> motor. This would prevent any self-breaking action. Comments?
>
>
>
>
>