Re: terminology help for newbie (pleeze<=)>

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

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

MOV - Metal Oxide Varistor - a component used to suppress voltage transients
(an MOV is what's inside a lot of "surge supressors").  It has a fairly high
resistance until the voltage gets over a threshold, at which time the
resistance drops (but not to zero).

Coupling - in TC terms: Any time you have a transformer with two windings,
the magnetic field from one winding is coupled, more or less, to the the
other winding.  The tighter the coupling, the more similar the magnetic
fields are.  Perfect coupling is 1.0. Perfect no coupling is 0.0.  For air
core transformers (i.e. a tesla coil), the easy way to vary coupling is to
move the windings closer (more coupling) together or farther (less coupling)
apart.  For a spark gap based coil, you don't want 1.0 coupling (which is
good, because it is hard to get).

kVA - kiloVoltAmpere - a way of rating transformers (and inductors, etc.).
14000 volts at 1 amp is 14000 VA, or 14 kVA.  VA is used instead of Watts
for a variety of reasons, mostly having to do with active and reactive
power, power factor, etc..  Think of a kVA as a kilowatt, for convenience.

Speed control of an induction motor (which is what you likely have) is a
somewhat tricky area, and one I won't get into.
 Essentially, you need to control the frequency of the voltage you feed it,
but you can vary the speed somewhat by changing the voltage, especially for
a small motor.
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, October 11, 2001 5:00 PM
Subject: terminology help for newbie (pleeze<=)>


> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<jbdetails-at-prodigy-dot-net>
>
>    I am new to the technical side of electronics so sometimes terms
> used are a little confusing. Could someone possibly point me towards
> a web site or explain to me what "MOV, Coupling, KVA, and maybe
> somewhere that explains AC motor speed control. (specifically a 1/3hp
> AC motor that has windings around the rotor, no windings in the
> rotor, and doesn't require a capacitor)
>
> Thanks,
>     Bob Bozarth
>
>
>