Re: John Freau's SRSG motor controller

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

Original poster: "Dr. Resonance by way of Terry Fritz <teslalist-at-qwest-dot-net>" <resonance-at-jvlnet-dot-com>


When the variac is "growling" it usually helps to either add a 1 Ohm high
power resistance in series with the power reactor or increase the inductance
a bit in the reactor --- usually 10 more turns.

The power xmfr may be causing partial saturation of the reactor and for a
brief period of time may suck as much as double the normal current throught
the reactor.  I know if you are averaging 28-32 Amps on the Ammeter a
standard 12 AWG. wire will not work on the reactor --- it gets hot enough to
almost melt the insulation.  We usually use 9 AWG on our reactors for a
typical pig coil running 28-35 Amps into a .05 or .06 MFD cap.  We usually
throw in a nice 100 CFM fan next to the reactor to keep everything cool.

Ed Wingate might want to comment on this as well because he has some nice
variable reactors using modified welding units.  I'm sure Ed has gathered
some data on this phenomonem.

Dr. Resonance

 > I looked at the input current and capacitor current with my controller
 > setup at about 1/4 turn on the variac.  This is where it "growls" the best
;-))
 >
 > The wave forms are stunning!  Here is the AC input:
 >
 > http://hot-streamer-dot-com/temp/03-05-31-01.gif
 >
 > and the capacitor current:
 >
 > http://hot-streamer-dot-com/temp/03-05-31-02.gif
 >
 > Those 30 amps spikes are a combination of "everything".  But they seem to
 > be high enough in frequency so the varaic does not saturate.  They just
 > help it to growl ;-))
 >
 > I am just running a 10 amp powerstat and 140uF of capacitance which seems
 > to work well with both my motors.  Here are some exciting pictures of the
 > lab setup :-D
 >
 > http://hot-streamer-dot-com/temp/03-05-31-03.jpg
 >
 > http://hot-streamer-dot-com/temp/03-05-31-04.jpg
 >
 > Cheers,
 >
 > Terry
 >
 >