Re: Async vs. Sync

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

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Michael,

Tesla list wrote:

> Original poster: "Michael by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<MFraylich-at-btinternet-dot-com>
>
> Dear Tesla,
>
> what is the difference between sync and async? Is async a DC motor
> that is run from the mains? Why not just use a normal AC motor that
> spins at 3000RPM and triggered by the peak voltages of the caps or by
> an obit or autocoil?
>
> Michael

A sync gap is sync'd to the mains frequency and an async is not. For
example (60Hz here), a 1750 rpm
motor is an async AC motor. It is not locked to the mains 60Hz frequency. A
sync motor is locked
onto the mains 60Hz frequency. A DC motor is not really either. It is a DC
motor and the rpm varies
with dc voltage applied. For example, I use a 30VDC motor to wind my coils,
and wind around 5 volts
applied. This gives low speed and low torque which puts tension on the wire
without breaking it and
allows a low speed for winding. I have a larger DC motor I use once in
awhile for a DC Drive Spark
Gap Motor.

An AC ASRG spins at the specified RPM based on the motor RPM rated speed.
We typically use these
motors and modify them for sync operation (grinding flats on the rotor).
See Terry's website for
details on this. I personally ground 4 flats on a 1750 RPM Async motor
rotor and reassembled. I
tested it with a digital tach and it was right on 1800 rpm (normal for 60
Hz). It's a 1/3HP motor
and handles my 10.6 inch (electrode rotational diameter) with plenty of
torque. The disk itself is
12". Set screws hold in the tungsten electrodes. Simple and sweet.

Oops, I'm rambling,
Take care,
Bart