beginners t.former hookup question??

[Ryan]

:confused: TWO phase line 7200 on the high side and I want 480 on the low side of the pot. 3 secondary bushings, 2 primary bushings. Need it for irrigation account, (is this an example of a scott T hookup) Will someone explain to me how to hook this two pot bank up.
Thanks for helping a beginner out.

[topgroove]

Sure... if its singe phase 480 your looking for and your primary in a 7200 wye the high side on your two pot bank is pretty simple. On tub 1 H1 goes to phase A H2 goes to ground on tub2 H1 goes to phaseB andd H2 goes to ground. Now on the seconary side all you do is put the two secondary coils in series. X1 on tub1 is connected to X3 on tub2. Now you will have 480 volts across X3 on tub1 and X1 on tub2. I hope I explained it clearly.

[Johnny Balls]

Ryan,
If you using 240 volt low side voltage transformers I would do as topgroove recommended on the low side connections. However use the SAME phase in each H1 bushing otherwise you will make a delta connection and will not get 480 when you series the coils.

[Ryan]

I thought you would have to use the same high side bushing, if you series the x1 and the x3 bushing you can get two legs of 480, IS THERE A WAY TO GET THREE LEGS OF 480 instead of just the two, (something I could rewire with the x2 bushings?) I would only have 240 if I just took the remaining x1 and x3 down right?? Somehow I need to get three legs of 480 out of a two phase line with two pots??

[shocker]

if you find a way to get 3 phase 480 out of 2 120/240 pots then i would like you to come over and look at the wireing on my toaster,dam thing keeps burning my bread

[Ryan]

There's two 240/480 pots. not 120/240

[harley]

you build a 480 straight power bank using 2 transformers buy building it like an open delta bank without the nuetral buss.

[dbrown20]

Get a Kurtz Lineman and Cablemans Handbook and also the GE transformer book on distribution hookups. That way you won't having to ask these questions. dbrown20

[Ryan]

Actually Dbrown this is the first time I've ever asked anything on here. I own both the books you mentioned but they don't cover this situation. The GE book doesn't have much on two phase lines.
If I hook them up TWO PHASES 7200 and series the x1 and x3 bushings ill get my 480, IS THERE A WAY TO GET the third leg of 480 volts using the x2 bushings. :confused: :confused: Using only two transformers

[dbrown20]

Ryan, I own both books also. Without looking I'm quite sure there a drawing of a 2 pot bank as you describe. You have to be more specific when describing things. Is there a system neutral present? Is it a Wye system with 2 phases and a system neutral present? Is the voltage 7200 phase to ground or phase to phase?

2 pots of additive polarity, hooked into a 2 phase line with system neutral present, assuming they are the right pots will most assuredly give a full 3 phase 480 volt hookup on the secondary just as the book shows. Using both H1's on each pot for the primary side, and hooking the H2's to the system neutral would complete the primary side. On the secondary side, an X3 of one pot would join the X1 of the other pot. This junction would be one secondary phase. The remaining X3 of one pot and the remaining X1 of the other pot would make up the remaining 2 phases just as the book shows. This would be an ungrounded delta with your voltmeter showing a nominal 480 in three positions. How much plainer can it get?

It doesn't matter if the pots are additive or substractive actually. One hookup is the one of lesser displacement called the America standard and the other is the alternative. They are 180 degrees apart. The only thing the book doesn't describe is the swapping of high and low side that some people may do. Go back and break out your GE book. dbrown20

[ROPEBLOCK]

i thought you had to know your trans. banks before you became an apprentice

[Ryan]

I guess if I knew everything I wouldn't be an a apprentice. Sometimes classroom doesn't help until you have practical hands on experience.

[BigClive]

i thought you had to know your trans. banks before you became an apprentice

Meeow! Is this an invitation to test YOUR knowledge? ;)

I know plenty of Journeymen who come unstuck on anything outside the ordinary.

[Ryan]

Well if you series your 240/480 x1 and x3 bushing you get your one leg of 480, I would have to series the remaining x1 and x3 bushing for the second 480. That leaves nothing left for my third leg of 480. I think ????????If I took them down like you said I'd have one 480 leg and two 240 legs. and that wont work for an irrigator.

[ROPEBLOCK]

YOU DONT HAVE A NEUTRAL LEAD SO YOUR USING BOTH COILS TO GET YOUR 480. SO BUILD IT THE SAME AS A OPEN WYE-DELTA JUST LEAVE OUT THE NEUTRAL LEAD.YOU WILL GET 3- 480s. dont worry about phase to grounds its 0+volts just confuse you.i think this is what your asking

[dbrown20]

Ryan, either you're very stupid or just a chain jerker. If you have the aforementioned books you must be retarded. Which is it? dbrown20

[Johnny Balls]

Ryan, either you're very stupid or just a chain jerker. If you have the aforementioned books you must be retarded. Which is it? dbrown20
The answer to that question Mr. dbrown would BOTH. My final answer.

[dbrown20]

Ryan, let's just start out with a single phase transformer hookup. After you master that then you can go to banks. dbrown20

[BigClive]

The question is... is he trying to get a three phase secondary from a two phase primary?

I dunno. here in the UK everything is so simple with our standardised 240/415 system. Homes 240V, small factories, office sand shops 240V. Big offices.shops and factories 415v. It's that simple.

[wayne440]

I think the OP is confusing having 2 phases of 3 available, with a "2 phase" system. True 2 phase is all but obsolete, he probably has 2 of 3 phases there.

[BigClive]

Even then, he's not going to get a proper 120 degree apart three phase supply if there are only two phases of a three phase primary.

That's assuming he's actually trying to make a three phase supply as opposed to just three sources of 480.

[topgroove]

true its not true 3 phase power but in rural areas in America its quite common.Its mostly used for water pumps on large farms. The power companies are usually municapalities where the cost of running three phase power is cost prohibitive.

[BigClive]

So are they single phase pumps then?

[topgroove]

no its actually three phases of in this case 480. its what we call open delta.

[BigClive]

I'm visualising this as two 480V transformers with their windings commoned to create a centre tap with 480 either side?

I take it that the motor loads are only really expecting a single phase or are using electronic drives?

[toptie]

Ryan the best rule of thumb is not to guess on a customers voltage. f you are at home and can play, do it. Otherwise if you are unsure tell youre superiors you are not trained in that situation and let it go . There should not be any embarssemnt on your part, you are just taking the safe route!

[Johnny Balls]

Ryan,
The attached diagram may be what you need for the 480 hookup.The low side voltage of the TX's in the example are 240 volt, you said you had 480 volt low side TX's. The low side connections would be the same. I'm not sure what the primary side of your transformers require, but hopefully you do. I agree with dbrown that maybe you should start with the basic single TX hook ups. Still not convinced you know more than you are letting on and doing a little "chain jerking", either way I hope this helps somebody.

[shocker]

This diagram is exactly what he wants except for the neutral hookups on the low side and of course 480 transformers.if he has the books i dont see why he even needs to ask.fishy.

[Ryan]

Ryan, either you're very stupid or just a chain jerker. If you have the aforementioned books you must be retarded. Which is it? dbrown20


The answer to that question Mr. dbrown would BOTH. My final answer.



SHEEEESH, I'll bet you and Johnny Balls are the type of guy you have on every crew. I'll never for the life of me figure out why there has to be one on every crew?? Ohhh well, guess that's what makes everyone different.

Way to take the high road Chief.

Thanks for the help I'm making this more difficult than it had to be, YES I OWN BOTH BOOKS but I didn't see the exact situation I was looking for. Thanks for the help those that replied. Now lets get back to DBROWN20.com to see what other exciting replies or questions he posts, this is his website isn't it. :rolleyes:

[dbrown20]

Admit it you don't even work in this trade. Right? dbrown20

[Ryan]

I know a lineman from Oklahoma, he said his foreman was an asshole?
He prob. knew you. :D

[dbrown20]

What grade are you in High School? Bet you don't dare say who you work for. Ryan when someone knows there is a drawing in a book that tells you exactly what wire to connect and someone even posts the drawing, what are we to think? According to your bio. you were born in 1964. Give me a break. dbrown20

[Ryan]

Jeez guy, I don't feel the need to drag this out..........
Best of luck to you, stay safe.
Ryan

[Linemo]

Ryan just steppin out on a limb here D Brown is a very smart no nonsense Lineman with Intelligence and years of experiance too boot JMHO but listen well and you will learn much