Variable Speed SRSG

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

Original poster: "Jeremy Scott by way of Terry Fritz <teslalist-at-qwest-dot-net>" <supertux1-at-yahoo-dot-com>

Hi list,

With your input, I think I've finalized my design
plans for the Basic Stamp controlled RSG:

Motor:

I found a 120VDC motor for sale at www.sciplus-dot-com
that runs 2HP -at- 4800 RPM (have to purchase)

Disc:

12" G10 with eight 1/4" tungsten electrodes.
Drill chuck :) 2HP should have no problem
spinning this right?

Gap:

Four stationary 1/4" tungsten electrodes mounted in 1"
sq x 7" long copper bars.

Max BPS: 80RPS * 8 electrodes * 2 gaps = 1280

Control:

Basic Stamp PWM + one very big (or many parallel)
MOSFET's

Feedback:

Whichever works best:

1) Neodyium magnet/Hall Effect sensor
2) LED/Photo Transistor
3) Some software solution, function of pulsewith
etc...

Bunch of logic IC's to count sensor pulses so the
stamp doesn't have to. Clock signal can come from 60Hz
:) Stamp will read RPS in binary from logic circuit.
Most likely will have the sensor trigger
four times per rotation for extra granularity.
(also balances the disc...:) ) This keeps the stamp
from being occupied in a pulse counting loop. The
clock signal will be tied to a basic stamp interrupt
such that the stamp can check the speed of the motor
several times per second.

Phase control:

As suggested, vary the speed of the motor for a fixed
amount of time. ie 1799 RPM will rotate through
360 degrees of backwards phase shift in 6 seconds.

Power:

120V:120V Isolation transformer
one very big bridge rectifier
one very big capacitor (may not need this)













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