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Re: 15kVA 12.6kV pole pig (fwd)
---------- Forwarded message ----------
Date: Sat, 16 Jun 2007 15:27:30 +0000
From: David Rieben <drieben@xxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Cc: drieben@xxxxxxxxxxx
Subject: Re: 15kVA 12.6kV pole pig (fwd)
Tim,
Ok, wow, that is rather strange. Logic would dictate that your transformer
would react the opposite to what you are describing -- a loud core satura-
tion hum when attaching 240 volts to the center LV and one of the outer
ones (that is the 120 volt tap) and better perfromance when attaching 240
volts to the outer two LV terminals (that would be the 240 volt tap). O yea,
I almost forgot to ask you about this issue. Is there a copper ground strap
between the center LV terminal and the case of the outer tank? Most single
phase pole trannies do come with one of these grounding straps and if it
is there, you will need to remove it and leave this terminal unconnected
"floating" for Tesla coil use. That may explain why you are getting saturation
when running 240 volts through the 240 volt winding - it's being shunted out
to ground half way through the LV winding.
BTW, that transformer sounds like a nice catch ;^))
David Rieben
-------------- Original message --------------
From: "Tesla list" <tesla@xxxxxxxxxx>
>
> ---------- Forwarded message ----------
> Date: Sat, 16 Jun 2007 10:28:24 -0400
> From: timjroche@xxxxxxx
> To: tesla@xxxxxxxxxx
> Subject: Re: 15kVA 12.6kV pole pig (fwd)
>
>
> david,
>
>
> Â Â yes, i am sorry, it is Tim, thank you. according to the factory
> nameplate, it is a 120/240 LV. FYI -Â HV has a 5 position switch for
> incramental voltages from 12,600 down to 10,500 VAC.
>
> -----Original Message-----
> From: Tesla list
> To: tesla@xxxxxxxxxx
> Sent: Sat, 16 Jun 2007 6:40 am
> Subject: Re: 15kVA 12.6kV pole pig (fwd)
>
>
>
>
>
> --------- Forwarded message ----------
> ate: Sat, 16 Jun 2007 14:08:31 +0000
> rom: David Rieben
> o: Tesla list
> c: drieben@xxxxxxxxxxx
> ubject: Re: 15kVA 12.6kV pole pig (fwd)
> Hi , is it Tim?
> Are you sure that your newly aquired pole transformer isn't rated for 240/
> 80 on its low voltage terminals instead of 120/240 since you are getting
> etter performance by center tapping the LV terminals?
>
> avid Rieben
> -------------- Original message --------------
> rom: "Tesla list"
> >
> ---------- Forwarded message ----------
> Date: Sat, 16 Jun 2007 01:57:34 -0400
> From: timjroche@xxxxxxx
> To: tesla@xxxxxxxxxx
> Subject: 15kVA 12.6kV pole pig
>
> i have recently went from two Westinghouse PT's (about 5kVA) to a 15kVA
> pole XFR. Holy Squirrelly!! i am running SRSG 3600 RPM 4flying (.5"
> tung.)/2 station (.5" german silver). 0.1 uf hipotronics 70kV RMS tank
> cap.
>
> my biggest issue, besides the obvious current limiting, is getting the gap
> to quench. went to 8 pole flying and basically made a jacobs ladder around
> the rotor. like no quench at all. so back to 4 flying. am i way off or is
> this a impedance problem on the LV side of pole XFR? BTW - i get nothing
> but 60 cycle hum or saturation using 220 VAC RMS across the LV windings.
> yet if i hook up my 220 VAC RMS with one leg on the CT or hooking it up
> like 110 VAC RMS, i get much better performance. for those interested, i
> was using a 1256 variac as voltage control and a 1156D as phase ajustment.
> Now i have put a 3-stack 60 amp inline current limit. i first put 220
> across it and turned the wipers till i was pulling 40 amp. then put it in
> series. it is still only a 3 to 4 foot streamer. with my PT's, i can get 2
> -3 streamers 6 to 7 foot long.
>
> Thoughts?
> Suggestings?
> Ideas?
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