Re: SRSG Phase Controller

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "canska" <canska@xxxxxx>

Thank you, John, this is exactly what I wanted to know!

I wonder if it is possible to derive a formula for obtaining the necessary 
capacitance. I assume the main variables in this situation are  parameters 
of the particular motor use in the SRSG. Perhaps we can assemble details 
from everyone using this system to see if there is a relationship.

I'm curious on this matter because a buffet of suitable motor-run 
capacitors isn't easy to come by for the trial and error approach, and I'd 
imagine such a formula would be generally beneficial to the community.

Thank you much!

Rob Judd - canska@xxxxxx
http://homepage.a5.com/~canska/tesla


>Original poster: FutureT@xxxxxxx
>In a message dated 7/15/05 11:18:24 PM Eastern Daylight Time,
>tesla@xxxxxxxxxx writes:
>
>>Original poster: "Rob Judd" <canska@xxxxxx>
>>Has anyone successfully used this phase controller with a larger motor?
>
>Robb,
>Well I was being cautious at my website and was reporting what
>some others had seen when using larger motors.  However I heard
>that the controller has been used with excellent results with motors
>up to 5 HP or larger.  I believe that Kevin Eldredge's  Bigggg Coil
>uses a 5HP motor for his controller.
>
>It's very possible that the folks who had the braking problem used
>a capacitor that was too large.  I forget.  In any case you don't
>want the rotor to shear off as the system shuts down.  If the
>rotor is securely mounted to the shaft, this shouldn't be a problem.
>Yes, self-braking is the issue, not self-breaking.
>
>I've only used the controller for motors up to 1/4HP, so others may
>be able to tell you more about their results.
>
>In any case you won't have problem using a 0.5HP motor.
>
>>I do hope that was intended to mean "self-braking", not breaking! Still, its
>>not good either way.
>
>It's just something to be aware of.  You'll see right away if the
>motor has a tendency to stop too quickly.  Also if I remember
>correctly, simply by turning the variac to a suitable position
>will stop the self-braking tendency.
>
>It is easily do-able and your motor will not be destroyed.  It is not
>really an issue at 0.5HP.  But it's best to select a capacitor that
>is the correct value for the system by looking for the 5 volt max
>resonant rise as I described.  The proper value cap must be found
>by trial and error.
>
>John