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wtdoor67
06-18-2008, 07:36 PM
Once upon a time. No that's not how it begins. You're not gonna believe this shit. That's it.

Just kidding.

The town only had one primary voltage. 12470 four wire wye. It was an informal place with one crew and a part time warehouseman. The warehouseman pretty much thought he was on top of it. He overheard the foreman on the phone with the engineer and they were discussing a job to "close the delta" at a small machine shop in town. This place was currently operating with a 2 pot bank 120/240. Later the foreman told the warehouseman. "We're gonna make a 3 pot bank over there at Joe's Machine Shop." "Looks like Monday." "Do you need me to give you a material list?" "Engineer said he would send the paper work next week, but we'll just do an after the fact and catch the paper work later." The warehouseman said. "Nah, I don't need any material list, I know what you need." The foreman smiled and said. "Okay."

In the crewroom Monday the warehouseman gave the foreman a piece of paper with the transformer data etc. and said. "I got all your transformer information with the serial # and everything else." The foreman glanced at the paper and said. "Sorry bud, you're all screwed up. That won't work at all." The warehouseman said. "It's the same as what you've got up there."

Without even checking the material pile what did the foreman see that told him the warehouseman didn't know jack?

MEGA81
06-18-2008, 09:03 PM
Im going to guess that he gave the foreman a transformer with the same KVA rating. And the foreman needed to close the bank with a larger pot.

wtdoor67
06-18-2008, 09:55 PM
Nah. Nope. Nada.

Hemingray Insulators
06-18-2008, 10:55 PM
was the new pot set up for 120/208? or a single bushing pot? after that i aint got a clue lol. well impedance mismatch?

wtdoor67
06-19-2008, 07:45 AM
Okay Hemi. Stop and think. The information given to the foreman for transformer data contains all the info given on the transformer label. The impedance,(not important in such a bank), the secondary voltage, the primary voltage, the serial #, the manufactor and so on.

If the foreman realizes that the pot won't work what must he have seen on the paperwork and what kind of pots are in the current 2 pot bank? Now this pot put up by the warehouseman will actually work but it's not proper and the co. specs don't allow it.

If it was set up for 208 it would be a simple thing to jerk the lid off and put the coils back in series. Also as stated before the impedance is not crucial in a Wye/Delta.

It's fairly simple once you picture it.

You're on the right track.

Hemingray Insulators
06-19-2008, 04:38 PM
ok, so it is being used for a wye on the primary which means is should be around 7200, was the primary wound for 12470 and NOT a dual voltage trans in which you could only use it in delta on the high side? that or is it a CSP? after that i'm kinda lost :confused:

Pootnaigle
06-19-2008, 05:38 PM
Ummmmmmmm how bout the foreman needed 3 pots with 2 primary bushings instead of 3 singles.

wtdoor67
06-19-2008, 06:10 PM
Yeah, but I wanted to make em work harder on it. The information on the label contains a clue that I wanted them to pick up on. Know what it is Hemi? If you don't, go and break out your book. I know you got one.

I figured some old salt would know right away what the deal was.

wtdoor67
06-19-2008, 06:23 PM
Here's you another simple one Hemi. The new grunt showed up on Mon. He said he had already about 6 months experience. Everybody shot the bull with him for a little while and then they got in the old El Camino and drove to the job.

The 2 linemen tooled up and prepared to climb the pole. The foreman said. "Okay clumey, get em a handline ready." The hand line was in the sheave and had an eye made in one end and a back splice or crown knot in the other end. It was not together at the moment as it had been left that way the previous Friday. The new grunt looked at it a sec. and immediately tied the 2 ends together with a square knot. Without looking one of the linemen hooked it on his belt and climbed up and safetied off. When the knot was sent up with the drill etc. the linemen quickly gave him a tongue lashing for the square knot.

What kind of knot should he have tied?

Hemingray Insulators
06-19-2008, 07:34 PM
Yeah, but I wanted to make em work harder on it. The information on the label contains a clue that I wanted them to pick up on. Know what it is Hemi? If you don't, go and break out your book. I know you got one.

I figured some old salt would know right away what the deal was.

damn it lol, i forgot about havin to float the neutral on a wye/ delta:rolleyes: an no i anit got a book..............yet...i am gettin one soon tho.

wtdoor67
06-19-2008, 08:49 PM
Okay Hemi. Answer the knot question.

On the pot label it may say 12470/7200 or it may say 7200/12470. What's it mean? Come on Brian.

Hemingray Insulators
06-20-2008, 03:59 PM
Okay Hemi. Answer the knot question.

On the pot label it may say 12470/7200 or it may say 7200/12470. What's it mean? Come on Brian.

i am not sure what knot to tie, all the handlines i have seen/ used have had snaps on the ends, bowline is my most used knot but i'm not about to even try to guess what the answer is................

7200/12470 the primary voltages it will take, 7200 in a wye and 12470 in a delta. and i think you have to change the tap on the coils to get either of the other of the two?

MEGA81
06-20-2008, 04:24 PM
And a square knot was bad form, my guess is surgeons knot or weavers knot. Double fishmans could work as well i guess. But I would also pick up a hook and snap at some point and splice them in to the rope, to bring that handline up to modern times.

Edge
06-20-2008, 06:39 PM
Nice damned thread ya got going here 'Door... the apes should get a lot more ?'s and hell it's good for us JL's too! (I like to brush out the old cobwebs sometimes!!!)

Hemi, If you PM me or email me your address I'll send ya a fuggin Lineman's bible... but only if you promise me you'll quit hauling pole around in your back yard on your shoulder and shit... your gonna break your balls for your time doing that shit!

and as far as the hand line ? goes it may not be your right answer Wt... but I know on the wood pole hiline if it wasn't an inside bowline with about a 4 foot tail what ever you just sent up was coming back at you at terminal velocity!!!

for what it's worth...

Edge

Lineman do it with the Lights on!

wtdoor67
06-20-2008, 07:20 PM
You guys got to carried away. It's usually something simple. With the handline with an existing eye you just use that eye and make a single sheet bend.

On the pots. The order of the primary voltage letters are the clue. If the smaller voltage numbers are in front it's a double bushing high side, if larger number is in front it's a single bushing.

If you take the bitter ends of a line and tie it in the form of a bowline, turn it over and you'll see it's just a sheet bend.

If you want a definitive book on knots, get the Ashley Book of Knots.

Transformer trick. With a frozen steel water line take a 7200 volt pot and hook it to 2400 and you can use the leads to thaw out waterlines. I've never seen it done but a guy told me he had and I didn't have any reason to doubt it. I know they do it with welders sometimes. Also have know of them setting their houses on fire doing this. Better have somebody standing by with a fire exstinguisher.

Another guy, (an REC hand ) told me they used to test single phase Kyles by hooked them to the truck battery, covering the battery with a rubber blanket and then closing the handle of the Kyle. This they did just before putting them on the pole. Kinda crude, but I bet it would work. I doubt if the safety department would approve it. I asked what was the rubber blanket for? He said just in case the battery blew up.

I used to have a bonafide written instruction for clearing a regulator in dire conditions. You tonged the solid blades (if it was so equipped) or mounted cutouts, whatever. When you had a good idea what it was carrying then you put in fuses just a little larger than the load and closed the by passes. This was supposed to blow the fuses that you had just installed and of course clearing the regulator. Always wanted to try it.

wtdoor67
06-20-2008, 08:40 PM
i am not sure what knot to tie, all the handlines i have seen/ used have had snaps on the ends, bowline is my most used knot but i'm not about to even try to guess what the answer is................

7200/12470 the primary voltages it will take, 7200 in a wye and 12470 in a delta. and i think you have to change the tap on the coils to get either of the other of the two?


Brian, you do so well most of the time and then sometimes you just seem to guess. An ordinary pot such as this only has 7200 turns on the primary windings. Since there are only 7200 turns then it can only take a max of 7200 volts, no matter if it's a single bushing or a double bushing high side. It has to be double bushing in order to operate in a bonafide delta system. A pot like this would operate in a 12470 wye system with the neutral available or a 7200 volt delta system.

However there is one sort of an exception. If you have for example an oil field system it is not uncommon to have the old ungrounded Wye system where they just string 3 wires without the neutral being brought out from the sub. All the single phase setups, 2 pot banks and Wye secondary banks will require pots with winding turns equivilent to the phase to phase voltage. They will have to be delta on the high side.

The one exception is the 3 pot Wye/Delta. Then you can use the lower rated pots which in this example would be 7200/12470 while the aforementioned pots can be 20.8 or there abouts as long as they have about 12000 or so turns on the primary side.

With the Wye/Delta since the high side "floated" neutral is separate from the grounds and system neutral then the lower rated pots will work. I have seen people ignore this and just go ahead and use the higher rated pots and make a delta/delta as they didn't want to mix up the type of pots in a particular location.

Hemingray Insulators
06-20-2008, 10:05 PM
lots of good info, thanks............ya i was guessing, because i didn't know, but now i know a bit more, thanks :)


Brian, you do so well most of the time and then sometimes you just seem to guess. An ordinary pot such as this only has 7200 turns on the primary windings. Since there are only 7200 turns then it can only take a max of 7200 volts, no matter if it's a single bushing or a double bushing high side. It has to be double bushing in order to operate in a bonafide delta system. A pot like this would operate in a 12470 wye system with the neutral available or a 7200 volt delta system.

However there is one sort of an exception. If you have for example an oil field system it is not uncommon to have the old ungrounded Wye system where they just string 3 wires without the neutral being brought out from the sub. All the single phase setups, 2 pot banks and Wye secondary banks will require pots with winding turns equivilent to the phase to phase voltage. They will have to be delta on the high side.

The one exception is the 3 pot Wye/Delta. Then you can use the lower rated pots which in this example would be 7200/12470 while the aforementioned pots can be 20.8 or there abouts as long as they have about 12000 or so turns on the primary side.

With the Wye/Delta since the high side "floated" neutral is separate from the grounds and system neutral then the lower rated pots will work. I have seen people ignore this and just go ahead and use the higher rated pots and make a delta/delta as they didn't want to mix up the type of pots in a particular location.

Hemingray Insulators
06-20-2008, 10:07 PM
ya, i promise i wont carry poles around anymore....dont have any more to carry around or replace anyways

oh, btw i might have trouble PMing you if you dont have your PMs enabled


Nice damned thread ya got going here 'Door... the apes should get a lot more ?'s and hell it's good for us JL's too! (I like to brush out the old cobwebs sometimes!!!)

Hemi, If you PM me or email me your address I'll send ya a fuggin Lineman's bible... but only if you promise me you'll quit hauling pole around in your back yard on your shoulder and shit... your gonna break your balls for your time doing that shit!

and as far as the hand line ? goes it may not be your right answer Wt... but I know on the wood pole hiline if it wasn't an inside bowline with about a 4 foot tail what ever you just sent up was coming back at you at terminal velocity!!!

for what it's worth...

Edge

Lineman do it with the Lights on!

Edge
06-20-2008, 11:01 PM
done


Edge

what do you mean "that wire's hot?"

wtdoor67
06-22-2008, 08:38 AM
How's the applying for apprentice positions etc. going? We're expecting great things of you.

Here's another quiz for you. You look at an ordinary house voltage pot. The label says 7200/12470 for the primary rating. Take this pot and install it in a delta configuration in a 4160 Wye system. What will your secondary voltage be?

Hook it in a single phase Wye configuration in a 4160 Wye system. What will your secondary voltage be?

Hook it up in a 7200 volt delta system. What will be your secondary voltage? It's just an ordinary house pot with 120/240 volt windings on the secondary side.

Now the 4160 system of course has a neutral available, so don't get confused and start guessing.

Now some might think all of this is bullshit, but over the years you will run into weird stuff probably. A guy told me on a storm once that a customer said his voltage was screwed up and so they went and took a look. A previous crew in the confusion had actually hung a 19.8 pot in a 7200 volt system and left. That was the man's problem. While you're at it, what would have been the secondary voltage on such a mistake?

lewy
06-22-2008, 09:22 AM
we have had things like this happen on dual voltage transformers 4800/16000 or 7200/16000 when the tansformer is on the wrong tap.
Bad when you put the high voltage into the low tap.

MEGA81
06-22-2008, 02:53 PM
How's the applying for apprentice positions etc. going? We're expecting great things of you.

Here's another quiz for you. You look at an ordinary house voltage pot. The label says 7200/12470 for the primary rating. Take this pot and install it in a delta configuration in a 4160 Wye system. What will your secondary voltage be?

Hook it in a single phase Wye configuration in a 4160 Wye system. What will your secondary voltage be?

Hook it up in a 7200 volt delta system. What will be your secondary voltage? It's just an ordinary house pot with 120/240 volt windings on the secondary side.

Now the 4160 system of course has a neutral available, so don't get confused and start guessing.

Now some might think all of this is bullshit, but over the years you will run into weird stuff probably. A guy told me on a storm once that a customer said his voltage was screwed up and so they went and took a look. A previous crew in the confusion had actually hung a 19.8 pot in a 7200 volt system and left. That was the man's problem. While you're at it, what would have been the secondary voltage on such a mistake?


70/140 volts for the first one.


40/80 volts for the second one

120/240 ?? for the third one.

90/180 for the last one
Thanks for the heads up on the ashley book of knots.

Hemingray Insulators
06-22-2008, 07:01 PM
well as far as apprenticeships, i'm still not 18 yet.....not til july 10th, at which point i'm sending in aplications to Cal-Nev, and mountain states, and that day i'm gonna go to the hall here (876) and sign the books, and see if i can get on as a groundman in the mean time...........

119.9/239.8 for the first one

69.3/138.6 for the second

120/240 for the third

43.6/87.2 fopr the last?


How's the applying for apprentice positions etc. going? We're expecting great things of you.

Here's another quiz for you. You look at an ordinary house voltage pot. The label says 7200/12470 for the primary rating. Take this pot and install it in a delta configuration in a 4160 Wye system. What will your secondary voltage be?

Hook it in a single phase Wye configuration in a 4160 Wye system. What will your secondary voltage be?

Hook it up in a 7200 volt delta system. What will be your secondary voltage? It's just an ordinary house pot with 120/240 volt windings on the secondary side.

Now the 4160 system of course has a neutral available, so don't get confused and start guessing.

Now some might think all of this is bullshit, but over the years you will run into weird stuff probably. A guy told me on a storm once that a customer said his voltage was screwed up and so they went and took a look. A previous crew in the confusion had actually hung a 19.8 pot in a 7200 volt system and left. That was the man's problem. While you're at it, what would have been the secondary voltage on such a mistake?

wtdoor67
06-22-2008, 08:52 PM
70/140 volts for the first one.


40/80 volts for the second one

120/240 ?? for the third one.

90/180 for the last one
Thanks for the heads up on the ashley book of knots.


Mega wins the drawing on this one. You need to brush up Brian. It's a matter of ratios Brian. A 7200/12470 pot with a 240 volt secondary would have a ratio of 30:1, therefore any voltage applied to it would have to be divided by 30. Hook a pot phase to phase as in a delta configuration and the applied voltage would be divided by 30. 4160 divided by 30 equals 140 for the full secondary coils and of course half of that is 70 for the mid point. Therefore 70/140.

In the second instance hooking a pot wye in a 4160 system would be exposing it to 2400 volts from phase to neutral. Divide 2400 by 30 equals 80 all the way across the winding. Thus 40/80.

In the third instance you are merely exposing a pot to its' correct voltage. 7200 volts delta hooked across a 7200/12470 pot will give its rated secondary voltage. 120/240.

In the 4th example I think you got balled up Mega. A 19920/34500 pot has a ratio between the 240 turn winding and the 19920 primary turns of 83:1. I would think the story given me by the guy indicated a pot hooked in a single phase Wye configuration from one phase to the neutral. Since the system this was done in was a 12470 Wye system this would have applied 7200 volts to this pot. This would have given approx. 87 volts all the way across the secondary winding. Therefore it would have had about 44/87.

Good job though mate for somebody who hasn't been to transformer school. I suspect you may have done a little reading ahead though.

MEGA81
06-22-2008, 09:16 PM
Thanks for the questions, it made for a good time today.

Hemingray Insulators
06-22-2008, 10:45 PM
ah, i know where i screwed up, i multiplied the 4160 by 1.73 because i didnt know that that WAS the phase to phase voltage, just for my info is voltage always given in phase to phase in the quizes you get? reason i ask is around here they always give the voltage phase to ground, except on transmission.......


Mega wins the drawing on this one. You need to brush up Brian. It's a matter of ratios Brian. A 7200/12470 pot with a 240 volt secondary would have a ratio of 30:1, therefore any voltage applied to it would have to be divided by 30. Hook a pot phase to phase as in a delta configuration and the applied voltage would be divided by 30. 4160 divided by 30 equals 140 for the full secondary coils and of course half of that is 70 for the mid point. Therefore 70/140.

In the second instance hooking a pot wye in a 4160 system would be exposing it to 2400 volts from phase to neutral. Divide 2400 by 30 equals 80 all the way across the winding. Thus 40/80.

In the third instance you are merely exposing a pot to its' correct voltage. 7200 volts delta hooked across a 7200/12470 pot will give its rated secondary voltage. 120/240.

In the 4th example I think you got balled up Mega. A 19920/34500 pot has a ratio between the 240 turn winding and the 19920 primary turns of 83:1. I would think the story given me by the guy indicated a pot hooked in a single phase Wye configuration from one phase to the neutral. Since the system this was done in was a 12470 Wye system this would have applied 7200 volts to this pot. This would have given approx. 87 volts all the way across the secondary winding. Therefore it would have had about 44/87.

Good job though mate for somebody who hasn't been to transformer school. I suspect you may have done a little reading ahead though.

wtdoor67
06-23-2008, 07:27 PM
I think that the phase to phase voltage is usually given unless the single phase is all that's present. However it can sometimes lead to a misunderstanding. If not understood, then ask is the usual rule. If someone mentions a voltage it is customary to just say. "Phase to phase or phase to ground?"

I agree that as far as I know transmission lines are always spoken of in the phase to phase manner.