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Re: phase shift

Original poster: FutureT@xxxxxxx

In a message dated 2/19/05 2:23:16 PM Eastern Standard Time, tesla@xxxxxxxxxx writes:


Bonjour , i'have construted this systeme, and it work's verry good, but i
don't undersatns the procedure to select the capacitot value .. i try 50µF ,
nows with the variac , i can obtain  nice and regular fire on the rotary
gap, i've not connected yet the TC , because i'm doing an enclosure for this
Rotary gap ,  (my motor is synchronous rated at 0.35A /110v , but i put an
  transformer 230V to 115V (in france 230V / 50hz) before the variac)..
Thank's you Terry , picture comming next..
Loïc From France




Hi Loic,

You're not the first person who did not understand my instructions
for selecting the capacitor value.  By the way 0.35A seems like a
very low current rating for the motor, you must be using a very
light-weight rotor disc?  If the capacitor is too large, you'll get
a lot of resonant voltage rise across the motor terminals at
certain variac know positions.  If the capacitor is too small,
the motor will not remain in sync throughout the range of the
variac.  The system will still work however if the capacitor is
a little too small or a little too large.  I like to see a 5 volt
resonant voltage rise maximum across the motor terminals.
To see this rise, connect a voltmeter across the two motor
terminals.  Then while the motor is spinning with the circuit
all set up (but no power to the tesla coil of course), monitor
the voltage across the motor terminals while rotating the variac
knob.  The voltage should change as you slowly rotate the variac knob.
At some point along the knob's rotation, you should see
a voltage rise above the 110V line voltage.  The voltage should
rise to 115 volts max.  If the voltage never goes above 110 volts,
that OK too.  If the voltage goes to 120 volts max, that's OK too.
If the voltage rises too much, then try a smaller value capacitor.
If the voltage doesn't rise enough, or sync operation is not
maintained for the full variac's range, then try a larger value
capacitor.

Cheers,
John


----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>> I show an electronic phase shifter schematic diagram
at my website at
>       http://hometown.aol.com/futuret/page3.html.
> Be sure to carefully select the proper phase capacitor value as
> the instructions indicate.  It is a trial and error process to find
> the correct value capacitor for this.