Re: New VTTC (how to remove shunts) (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Sun, 5 Aug 2007 15:41:49 EDT
From: FutureT@xxxxxxx
To: tesla@xxxxxxxxxx
Subject: Re: New VTTC (how to remove shunts)

 
In a message dated 8/5/2007 2:19:36 P.M. US Eastern Standard Time,  
tesla@xxxxxxxxxx writes:

John, I  have not modified my MOT. I will look into this but it's not too
obvious  how to get the transformer apart without damage. 


Hi Jim,
 
Yes, the options you mentioned are good.  
 
Shunt removal is not discussed all that often, so this may be of  value
to anyone that wants to remove them.  There is no need to
disassemble the transformer.  Here's how I remove MOT shunts by
hammering them out carefully.  They are usually glued
into place as a small pack of laminations.  Some MOT's have a lot of  glue 
at that area, some have only a little.  Maybe it's possible to melt  or
dissolve the glue but I have no knowledge of that.  If anyone  has
succeeded with that, I'd be interested to hear.  I try to select an  MOT
which has little glue in the shunt area, and adequate space for the
shunts to slide out in response to the hammering.  I suppose  they
could be pushed out with a press.  This would be cleaner and  more
controlled, but the press would have to be set up correctly so the
windings are not damaged.  The danger is general is that the  windings
will be damaged during shunt removal.  The lamination pack is
surrounded by thick paper or tape.  The laminations slide out
against the paper.  The paper provides some protective spacing 
between the windings and the laminations.  I use a punch a little  narrower
than the shunt pack, and I hammer so the central laminations of the
pack are driven out first.  Sometimes the laminations all move  out
together, other times not.  Usually there appears to be a best  direction
to drive out the shunts where they are lest likely to rub against the
windings.  Also be sure the punch itself doesn't scrape the  windings
during the hammering.  Usually once the laminations start  moving,
they start sliding out easier without needing so much force.   Another
approach would be to use a thicker punch, so all the laminations are
pushed out together.  This may endanger the windings more  however.
On some MOT's the laminations were so tight with glue that I gave up
and worked on a different MOT.  Sometimes it's necessary to  switch
to a different punch during the process to avoid damaging the  windings.
A square punch might work well but I didn't have one.  A square  piece
of steel could make a good punch.  It should be about 1/4" square  by
maybe 6" long.  Other folks may have other favorite methods they  may
wish to share.
 
John 



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