Step up transformer 240V to 480V 3 phase

Does anyone know where to find a surplused 240V to 480V 3 phase step
up transformer at around the 15 Kva range. I need one to power off of
my 15HP RPC to run my 480V 3 phase B&S Vertical mill. Los Angles,
Orange County, Inland Empire or San Diego area would be great. Don't
want to pay shipping for this weighty item ya know. Thanks.
trg-s338
Reply to
trg-s338
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See Winston's Laws. I got one cheap, a sittin' in the grave. Only 2500 miles away/
Karl
Reply to
Karl Townsend
I have one for sale.
snipped-for-privacy@algebra.com
i
Reply to
Ignoramus17493
(Snort!)
--Winston
Reply to
Winston
Gunner Asch fired this volley in news: snipped-for-privacy@4ax.com:
Due to core losses, copper losses, et. al., it won't work at the 2:1 ratio in reverse.
LLoyd
Reply to
Lloyd E. Sponenburgh
Odd..I do it regularly.
Shrug...
Gunner
"Lenin called them "useful idiots," those people living in liberal democracies who by giving moral and material support to a totalitarian ideology in effect were braiding the rope that would hang them. Why people who enjoyed freedom and prosperity worked passionately to destroy both is a fascinating question, one still with us today. Now the useful idiots can be found in the chorus of appeasement, reflexive anti-Americanism, and sentimental idealism trying to inhibit the necessary responses to another freedom-hating ideology, radical Islam"
Bruce C. Thornton, a professor of Classics at American University of Cal State Fresno
Reply to
Gunner Asch
Oh? That's news to me...
I know of no reason you can't do exactly that, and have done so at lower power levels.
Reply to
David Lesher
Gunner Asch fired this volley in news: snipped-for-privacy@4ax.com:
What, at no load? Gunner, I worked for a couple of years in the design and testing lab of Florida Transitron. I know just a bit about them, and have made many from scrapped parts of others, since.
A 2:1 step-down transformer is NOT wound precisely to 2:1 ratio, unless it's: 1)so lightly loaded as to constitute virtually no load at all, or 2) working at much higher frequencies than 60Hz (and even then loading plays a factor).
I know you don't understand that the secondary has resistance, or that the core has hysteresis losses; but they do.
(Gunner... again!)
LLoyd
Reply to
Lloyd E. Sponenburgh
David Lesher fired this volley in news:gvi3nb$2i8$1 @reader1.panix.com:
Ignorance doesn't make it work properly.
Sorry, but you and Gunner are reading off the same page, and it's not even in the electronics book.
LLoyd
Reply to
Lloyd E. Sponenburgh
Or 3) if it's in the size range being discussed here. The turns ratio is tweaked in smaller dry-type transformers, but is equal to the voltage ratio in larger units. The transition point varies between manufacturers: Acme compensates single phase xfomers below 1 kVA and 3 phase units below 15 kVA; Hammond drops the compensation at 3 and 6 kVA.
You do need to pay extra attention to the actual internal connections in 3 phase xformers when reverse connecting.
Reply to
Ned Simmons
Well, I got an A in EE421; and was proud of it. Granted it was 20+ years ago, but last I heard Maxwell, RH rule and that guy Thevenin still hold to this day.
Sure there are losses, all kinds of losses.. We got copper resistance losses, we got eddy current losses, you name it. But I don't recall any reason they don't apply no matter which way you go. Can you cite a source to back you up?
Reply to
David Lesher
Blink blink...so none of the transformers Ive installed are working?
Damn....bunch of miracle machines!!!!!
Gunner
"Lenin called them "useful idiots," those people living in liberal democracies who by giving moral and material support to a totalitarian ideology in effect were braiding the rope that would hang them. Why people who enjoyed freedom and prosperity worked passionately to destroy both is a fascinating question, one still with us today. Now the useful idiots can be found in the chorus of appeasement, reflexive anti-Americanism, and sentimental idealism trying to inhibit the necessary responses to another freedom-hating ideology, radical Islam"
Bruce C. Thornton, a professor of Classics at American University of Cal State Fresno
Reply to
Gunner Asch
Yes you do. And you have to adjust the voltage bars carefully to insure the proper output voltage.
Gunner
"Lenin called them "useful idiots," those people living in liberal democracies who by giving moral and material support to a totalitarian ideology in effect were braiding the rope that would hang them. Why people who enjoyed freedom and prosperity worked passionately to destroy both is a fascinating question, one still with us today. Now the useful idiots can be found in the chorus of appeasement, reflexive anti-Americanism, and sentimental idealism trying to inhibit the necessary responses to another freedom-hating ideology, radical Islam"
Bruce C. Thornton, a professor of Classics at American University of Cal State Fresno
Reply to
Gunner Asch
google "using a step down transformer in reverse"
Results...96,800 hits
Shrug, believe what you wish to. You are still wrong. Shrug.
Gunner
"Lenin called them "useful idiots," those people living in liberal democracies who by giving moral and material support to a totalitarian ideology in effect were braiding the rope that would hang them. Why people who enjoyed freedom and prosperity worked passionately to destroy both is a fascinating question, one still with us today. Now the useful idiots can be found in the chorus of appeasement, reflexive anti-Americanism, and sentimental idealism trying to inhibit the necessary responses to another freedom-hating ideology, radical Islam"
Bruce C. Thornton, a professor of Classics at American University of Cal State Fresno
Reply to
Gunner Asch
snipped-for-privacy@4ax.com:
Hi, Lloyd. The voltage ratios have to be the same, either direction, as they are physical quantities(turns counts). What doesn't work it the KVA rating, according to the electrician that installed the transformer to operate our convection oven for soldering circuit boards. He said to de-rate the KVA 10%. We have been running a transformer backwards to get 480 from 208 for about 4 years, now. 24/7.
Paul
Reply to
KD7HB
Easy thar, fellas, this ain't politics. All of you are right.
Xfmrs with smaller VA or KVA ratings are designed with a bit of fudge factor so they'll deliver rated voltage at rated load in spite of droop at rated load. Larger xfmrs are designed to have negligible droop at rated load because to do otherwise would result in unacceptable inefficiency and heating.
Reply to
Don Foreman
innews: snipped-for-privacy@4ax.com:
Ayup. I always calculate -20%
Gunner
"Lenin called them "useful idiots," those people living in liberal democracies who by giving moral and material support to a totalitarian ideology in effect were braiding the rope that would hang them. Why people who enjoyed freedom and prosperity worked passionately to destroy both is a fascinating question, one still with us today. Now the useful idiots can be found in the chorus of appeasement, reflexive anti-Americanism, and sentimental idealism trying to inhibit the necessary responses to another freedom-hating ideology, radical Islam"
Bruce C. Thornton, a professor of Classics at American University of Cal State Fresno
Reply to
Gunner Asch
snipped-for-privacy@4ax.com:
If a step down transformer is used in reverse, how would one ground the secondary (which now acts as primary)?
Reply to
trg-s338
innews: snipped-for-privacy@4ax.com:
You mean besides using that big green tab located on the frame of the transformer?
Or something else?
You do realize we are talking about 3ph transformers...right?
Gunner
"Lenin called them "useful idiots," those people living in liberal democracies who by giving moral and material support to a totalitarian ideology in effect were braiding the rope that would hang them. Why people who enjoyed freedom and prosperity worked passionately to destroy both is a fascinating question, one still with us today. Now the useful idiots can be found in the chorus of appeasement, reflexive anti-Americanism, and sentimental idealism trying to inhibit the necessary responses to another freedom-hating ideology, radical Islam"
Bruce C. Thornton, a professor of Classics at American University of Cal State Fresno
Reply to
Gunner Asch
Gunner Asch fired this volley in news: snipped-for-privacy@4ax.com:
You just confirmed my original statement. You never mentioned it's being a stepped secondary -- just "2:1 step-down".
LLoyd
Reply to
Lloyd E. Sponenburgh

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