RE: Three phase transformer arrived for saturation experimentation.

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "J. Aaron Holmes" <jaholmes@xxxxxxxxxxxxxxxxxx>

I wouldn't worry about smoking the thing unless the
current runs away from you.  For the unused HV and LV
windings, it's probably ok to just leave them
unconnected for now.  For a more permanent
installation with a pole pig for a load, I'd probably
opt for some MOVs or other transient suppression
devices across them to guard against voltage spikes
due to sudden introduction/removal of short-circuit
conditions on the other windings.  In any case,
shorting them doesn't sound like a good idea to me.

Regards,
Aaron, N7OE

--- Tesla list <tesla@xxxxxxxxxx> wrote:

> Original poster: "Philip Chalk"
> <philip@xxxxxxxxxxxxxxxxx>
>
>
>
> -----Original Message-----
> From: Tesla list [mailto:tesla@xxxxxxxxxx]
> Sent: Wednesday, 8 March 2006 11:08 am
> To: tesla@xxxxxxxxxx
> Subject: Three phase transformer arrived for
> saturation experimentation.
>
> Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>
>
> Hello Aaron, HV grp, and all:
>
>
> Input:
>
> There are three inner taps labeled 240v feels
> like a 10 or 12 AWG gauge wire. On the outter
> edge taps are (4) taps/winding these decrease
> closely lower R ohm increments beginning at .9 ,
> .8, .7,.4 ohms. This getting my Beckman.
> Inductance respectfully: .193, .179, .166, .004
> hmm. lablels respectively: +10v, 0, -10, 208v .
>
>
>
> Hi Jim,
>
> You probably realize, but the primary winding looks
> like this :-
>
> 	(Works for me in arial font)
>
>
>
>   240v __E___		To Feed With:-      Connect to:-
> 		)
> 		)
> 		)  12.8%		10v rms ac	  A & B or B & C
> 		)		
> 		)			20v		      A & C
>   208v __D___)
>      		)			32v		      D & E
> 		)
> 		)			198v		      C & D
> 		)
> 		)			208v		      B & D
> 		)
> 		)  79.2%		218v		      A & D
> 		)
> 		)			230v		      C & E
> 		)
> 		)			240v		      B & E
> 		)
>   -10v __C___)			250v		      A & E
> 		)
> 		)  4%
>     0v	__B___)
> 		)
> 		)  4%   <--- percentage of Total winding, from A
> to E.	
>   +10v __A___)
>
>
> The "to feed with" bit is basically just to show the
> different voltages
> you would expect to find on it, between pins, when
> fed the way it was
> designed.
>
>
>
> Let me make some assumptions the inner Hv winding
> should be disconnected from neutral and connected
> to the DC supply. This consists of a 35 amp 400
> PVI Bdiode on a pIII heat sink. For starters I'll
> use my 1256d since it is set up anyway. I am
> considering using filtration of 400uf separated
> by a 23 mh heavy choke 200UF out. Maybe that is
> unneeded but there won't be any harmonics or
> ripple as the current ramps up. I propose to use
> the 240v outer windings to go to my pig, no
> neutral. BTW the 208 winding seems heavier.hard to
> tell.
>
> Ok: those that have suffered through this so far
> and know the math, how much voltage/current do
> you estimate it will take to Sat this iron? What
> do I do with the input windings to the center
> control core, and the output winding of the outer
> controlled coils. Shorting em will heat things up
> fast. Load them maybe? Suggestions are requested.
> This may be easier with a three phase really
> heavy duty filter choke. I see them on ebay in fact
> have a few smaller
> ones.
>
> My pig is grounded as will this transformer. I
> have three 4500 watt hot water heaters for
> starters. I won't go past 9KW, it would be pity
> to smoke this perfect 883a transformer!
>
> Thanks Much,
> Jim Mora
>
>
>