480 from 120/240

Don't think it would work for 277/480. Only pots with a mid tap I think.

Probably talked about it on the other site but I did talk them into making a single phase 240/480 setup out of two 120/240 padmts. It's at a ball park at Hinton,Ok. Not your usual setup. They were amazed.

No I don't remember you talking about that.

I'm trying to visualize this. This has to be very similar to putting two ACBD xfmrs together in series to make a 120/240.

From what you describe here's my answer. (decided I'll do this padmount style diagram)



What do you think? Looks logical to me!

I'm looking at that diagram. If what I'm seeing is right there are a total of 4 different voltages you could get from that phase to dirt as is . 120 / 240 / 360 / 480.

Yeah it's possible to get several voltages. Easier to visualize with OH pots. Make the ground/neutral connection with X1 of one pot and X3 of other.

I think on the 277/480 with 2 phases and the neutral you could probably do it with 4 pots. Not with 3 though. Probably never need it though.

I'm sure y'all have seen this, but we used to have a couple of 3 phase banks providing 240/480 wye with 120/240 pots.
You just bond X1 on all the pots to ground, and X3 from each pot is a phase. You get 240/480 (well, almost 480).
I'm not sure why, other than maybe that is all the company had at the time to give service. We have since replaced with 240/480 delta.

wtdoor67 wrote:Yeah it's possible to get several voltages. Easier to visualize with OH pots. Make the ground/neutral connection with X1 of one pot and X3 of other.

Your right OH pots would be easier to visualize...BUT since I already have this one started

Alright, here's the corrected connection below if I'm understanding you correctly. The first thing that comes to mind for me is we're breaking a rule of only grounding it ONE time, now it's grounded twice so I'm a little skeptical of it. With this from the tie-buss of the two to ground I should see 480, and now from ground to either of the X2's I should be seeing 480, but now I'm thinking from X2 to X2 I should also see 480 and now I'm kinda wondering from x2 to ground I'm seeing 120.

But like I said the grounding of the coils twice in this configuration I'm not so saavy on.

wtdoor67 wrote:I think on the 277/480 with 2 phases and the neutral you could probably do it with 4 pots. Not with 3 though. Probably never need it though.

I'm not even going to attempt right now to try and come up with a schematic of how that could be done with 4. It'd be nice to play with some of those little mini transformers to test this on. You never know...work for some muni where whatever goes to save a buck.

hotwiretamer wrote:I'm sure y'all have seen this, but we used to have a couple of 3 phase banks providing 240/480 wye with 120/240 pots.
You just bond X1 on all the pots to ground, and X3 from each pot is a phase. You get 240/480 (well, almost 480).
I'm not sure why, other than maybe that is all the company had at the time to give service. We have since replaced with 240/480 delta.

I've never heard of it. I just drew it out on a piece of paper, basically moving the ground strap over to get straight 240 out of each pot then phase to phase 480 two wire. What threw me was what you were calling wye, and I can see it now with each pot acting individually.

Door, is this pretty much where you were going if that last schematic is wrong, only difference in what HWT is talking about is with 3 different primary phases?

What Hotwire alludes to is actually a Wye set up. It wouldn't be 3 phase 480 but rather 3 phase 416 as it's a Wye of course. If they had taps you could jack them up some.

Did run across one once. It was in an old grain elevator.

Your last drawing of the single phase pads is wrong I believe. First visualize as OH pots to keep from being confused. X1 and X3 will make the neut. The other X1 and X3 will have 480 single phase between them and 240 phase to ground or neut. Yes there's other voltages available but this is all we used.

yes.... your basicly making one long secondary coil with the two secondary coils 480 volts potential. Combining the two in series. you can place one ground anywhere along that coil.

transformer 1 transformer 2
A((((((((((((((((((((((((((((BC(((((((((((((((((((((((D____A((((((((((((((((((((BC((((((((((((((((((((D
by placing the ground here.................................^ your basicly center tapping that one really long coil giving you 240/240/480

rcdallas wrote:

wtdoor67 wrote:I think on the 277/480 with 2 phases and the neutral you could probably do it with 4 pots. Not with 3 though. Probably never need it though.

I'm not even going to attempt right now to try and come up with a schematic of how that could be done with 4. It'd be nice to play with some of those little mini transformers to test this on. You never know...work for some muni where whatever goes to save a buck.

Make your own! I had an insructor who made a bank with doorbell transformers? I want to make one but have been to damn busy! Wouldn't be hard? I believe it took 3 doorbell trnsfrms, some little disconnects, a few small knob insulators, fence post, grey pvc (to make the tubs), etc. I believe he had a 120v motor with a pully that he plugged in and had a belt that turned a small 12v generator with the leads going to the trnsfrmrs? He backfed'em so they were puttin out 120 and we had leads with alligator clips that ya just moved where ever to get your voltages? You won't be able to do all your banks obviously but most?

Prolly cheaper then those fancy trainning ones you can buy?

I built an open Y-Y bank with two single phase pad mounts. The engineers forgot that a Civil Defense siren needed 208. It is still there and was built 35 years ago.

wtdoor67 wrote:Did run across one once. It was in an old grain elevator.

Your last drawing of the single phase pads is wrong I believe. First visualize as OH pots to keep from being confused. X1 and X3 will make the neut. The other X1 and X3 will have 480 single phase between them and 240 phase to ground or neut. Yes there's other voltages available but this is all we used.

They do exist we have a lot of archaic things like this on the east coast. I guess the power pushed west they did the new stuff and back here we never fixed what was broken.

That makes it a bear to cut over when primary need to be changed:)

Randy have you gotten a GE transformer book yet? it's old school but pretty good, afterall it's not like there's been huge upgrades in tx's in the last 50+ years.

Mr. Door,

I cannot tell you how much I appreciate your post on any site you bring great knowledge to us. Thank you for defining the line between line mechanic and Journeyman.

L.A.Martin
Journeyman Div III
CVEC

I appreciate your plaudits. I not really so great or whatever but I as most hands have experienced a few unique things and am glad to share them. If I had written down a few other things I saw I would have even more to share. Were I to do it again I would keep a daily diary. All hands should do that I think as just memory is sometimes bad to rely on.

If you want my opinion, Steve Batts is about the most varied and experienced hand I have communicated with. He's a damn nice guy to talk with and I hope to meet he and Ruby sometime.

Glad to have you also over here on this board. It's gonna grow into a significant endeavor I think. I appreciate Dave for creating it.

I thought our union rhetoric had chased you away. Understand most of us, we worked on the properties of some great non union power companies and their hands are top notice. Some times our bullshit gets to one sided and we forget about those that equal or even beat our supposed KNOW IT ALL WELL TRAINED ASSES.
You would be surprised how technology and old systems jumped around to get the biggest city's lighted in the 1800s.
I worked on properties on the east coast, that has be gobbled up and no longer exist like Hartford Light & Power.
Worked secondaries that was above the pots in LAW&P. Strange 2 pot banks with 4 wire secondaries that I can't even remember the secondary voltage. Had my life threatened by Wild Bill Foley if I screwed up the Series Circuit in Colt Firearms park that was just listed as a historical system.

In 1967 I was broke and couldn't get a job except as a Lather & Plaster, trade I acquired before 4 years in the employment of Uncle Sam. I tore up some savings bonds and mailed to LBJ and told him to kiss my ass, and a fine way to treat a veteran. Well that did the trick. Got a letter from his secretary, Head of the Department of Labor, Texas Governor John Connally (this man wasn't no frigging Rick Perry). Got two job offers one with Houston Light & Power, and one with MA Bell (is a sorry MUTHER) Sorry Muther said I was to dumb and slow to work for them. Houston Light & Power jumped me over some sons of company hands to make me an apprentice. (I can still hear the crying fowl)
Any WHO Houston Light & Power started May 20, 1882, went bankrupt and restarted 1887. one hundred years before I went to work for them as a green know nothing without a clue. I was put on one of only three rehab heavy crews working 2,400 4,600 Wye and even 600 volts DC still being generated for the commercial freight elevators alone Buffalo Bayou from the Gable Street Power Plant. This was strange territory due to the fact that in those days commercial customers had to supply their own transformers and bigger customers even their own sub stations. You had some big transformers that required step-downs and even on the next pole buck banks, due to customer owned transformers with no tap changers.

YOU GOT TO REMEMBER THAT MY TOTAL DISTRIBUTION TRAINING WAS 2 YEARS ON THE POLE OJT. What I picked up in the next 42 years helps, but when DOOR and a few others stresses out this old HIGHLINER, He starts getting headaches and has to get into HI-Voltage pain Killers washed down with Everclear. So take it the old man and his two wire hookup, three wire fuk-up and 4 wire drag up.
As you can tell I am into the pain/Everclear solution already. Good night.

Two divorces wiped out the letters from all those big wigs, Connallys might be worth some money. Since he was riding with JFK.



SEE THE HISTORY OF GABLE STREET AND HOUSTON LIGHT & POWER

http://users.hal-pc.org/~lfa/BB45.html

Steve, I wish I knew half as much as you on heavy Transmision. I can build banks all day and put 336 and 795 back up, but when the really big stuff comes down...a guy like you is like an angel from heaven