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Re: synchronous motors

Original poster: FutureT@xxxxxxx

In a message dated 8/9/05 1:44:43 AM Eastern Daylight Time, tesla@xxxxxxxxxx writes:


Well, on the advice of many, I am looking into building a synchronous rotary
gap. Locally, there is a surplus house that has many motors. Often, some of
these have "sync" stamped in the plate with the details. Can such a motor
(given a good enough match in HP and RPM) be used for a snyc gap unmodified?
Does it still require modification? Does it mean something entirely
different?

Thank you for your words of wisdom.

--Ethersmith 


Ethersmith,

The best type is a salient pole type sync motor.  This will work
as-is.  There is another type of sync motor
called a hysteresis type.  This type will work but will lock up
at a different phase position each time you start the motor.
Generally folks avoid the hysteresis type for this reason.
Fortunately the hysteresis types usually have the word
"hysteresis" printed on them.

Generally sync motors will be either 1800 rpm or 3600 rpm
in countries using 60Hz power.  Either can be used for a sync
rotary spark gap.  If you find a motor that says 1500 rpm or
3000 rpm.  This is a motor designed for a 50Hz power country.
These motors will automatically run at 1800 or 3600 rpm
respectively if supplied with 60Hz power.  Many good
sync motors will not have the word sync printed on them.
Instead the printed rpm of 1800 or 3600 is the key to identifying them.

Regarding HP, the requirement depends on the weight of
your gap rotor.

You can also use an ordinary induction motor and grind
flats on the armature to make it synchronous.

When you do get the motor and build the gap you can use
my phase shifter circuit if you'd like for convenience in
adjusting the phase remotely and electrically, but the phase
can be adjusted in other ways also.

   http://hometown.aol.com/futuret/page3.html

John