Re: Saturable reactors?

To: tesla-at-pupman-dot-com
Subject: Re: Saturable reactors?
From: Jim Monte <JDM95003-at-UCONNVM.UCONN.EDU> (by way of Terry Fritz <twf-at-verinet-dot-com>)
Date: Thu, 17 Dec 1998 16:04:08 -0700
Approved: twf-at-verinet-dot-com


Hi,

>From what I read so far, this appears to be a conversion to a variable
inductor, not a variac. :(   With the rotor stalled, the motor looks
like a transformer with its secondary (the rotor) shorted.  Sliding the
rotor out decreases the coupling between the primary and secondary.
That sounds just like the variable air gap in a welder.  However, it
would not be hard to keep the rotor from rotating assuming single phase
power is applied to either a polyphase motor or a single-phase motor run
windings only.  For these cases, the motor will remain stalled.  Does
someone perhaps have more information on the motor -> variac conversion?

Jim Monte

>Date: Wed, 16 Dec 1998 08:05:04 -0700
>Subject: Re: Saturable reactors?
>Original Poster: alfred.skrocki.sr-at-juno-dot-com (Alfred A Skrocki)
>
>On Mon, 14 Dec 1998 18:46:36 -0700 in the Tesla List
>Scott Stephens <Scott2-at-mediaone-dot-net> wrote:
>
>>Somewhere I read about a hack that turns an AC induction motor
>>into a variac. You slide the rotor in and out of the stator. The
>>rotor windings are not used. The rotor is immobilized (but still
>>vibrates) and the stator windings are used.
>
>That would be some undertaking since you are in actuality locking
>the rotor in a stalled position while sliding it in and out. It would
>seem to me you would burn out the windings.
<snip>
>                       Alfred A. Skrocki
>                  Alfred.Skrocki.Sr-at-JUNO-dot-com