Re: Variac as sync gap tuner?
Hi Jim, Eddie, all,
> ><Eddie wrote>
> > Has anyone ever used a variac as a variable inductor for the purpose of
> > tuning a synchronous rotary gap by varying the phase lag? The nice thing
> > about this is that it could be remotely tweaked. I realize the inductance
> > would probably be excessive after a point but I'm just wondering if it
> > be an alternative to a pivoting motor mount.
> <Jim wrote>Actually, you could probably even do it in a more clever
> putting a capacitor across the winding of the variac, and perhaps some
> load to ground. The variac would be across two different phases, and you
> could fine adjust it quite nicely. How much phase shift do you need for
> a sync rotary....?? If it is only 45 degrees, then this kind of strategy
> would have real promise.
Well, I put up such a circuit into PSpice last night. I placed an inductor in
series (variac) with the motor load and a 1k resistor and 100uF cap to
parallel with the motor load. I put voltage markers on each side of the
load. Varying the inductor from 1mH to 100mH, I could get almost 45 degree
shift. I'll try it today on my sync gap and report. Seems like it should
am more curious if the motor will stay in sync as a voltage drop will be placed
across the RC combo. I used these values because I have the components on hand.