Transformers

[DerekC]

Im currently enrolled in a community college line school in the northeast. We have been studying transformers and im a little mind boggled on how the neutral conductor works on the secondary side of a single phase pole transformer. By my understanding the neutral carries the unbalanced load of the two phase conductors and is tapped off the middle of the secondary winding. I checked this by opening my home panel and amp probing my neutral and two phases and it worked out. What happens to the current that flows back to the transformer ?

[topgroove]

it completes the circuit. Lets say you could unplug everything in your house except one 60 watt lightbulb. When you turn on the light 60 watts of power flows from the X1 bushing through the bulb and then back out to the transformer to the X2 bushing using your neutral. Its a circle or complete circuit. This happens with every 120 volt circuit in your house. Lets say you have a 240 volt hot water heater in your house in this case your using the X1 and X3 bushings with a resistive load in between, in this case current flows through only the hotlegs.
Now things get real strange when you start to loose a neutral connection. If current has difficulty using the neutral to get back to X2 in a 120 volt circuit its gonna look for other ways to get back to the transformer. That means its gonna start using the other hotleg through a resistive load to get back to the transformer.
When you get to your first bad neutral call its always the same complaint. The customer will tell you half the house is real dim and the other half is real bright. when you get the fluke out and test the hotlegs under load you might find 80 volts on one leg and 160 volts on the other. (240 volts phase to phase).

loosing a neutral gets real expensive for a customer. In a blink of an eye you can lose your TV's , microwaves, fridge, stove any any thing else plugged in and in use at the time. a straight 240 applience like a heating element doesent know the difference except suddenly its got way more current flowing through it which may burn out the element.

hope this simple explanation help you out.

[Edge]

you need to go back to your books bub...

a single phase tx is just that single phase.... the secondary coil is one phase split in half....

x1 x2 x3

x2 is what splits it

if you move the neutral/case ground connection from x2 to either the x1 or x3 connection... you change the whole complexion of the coil...

now instead of having 240 phase to phase you might have 360 or one "leg" thats 120 to dirt and another thats 240 or maybe some thing even more fugged up depending on where you are...

hopefully some guys that are good with posting pictures and shit will chime in to help you out more than this... sorry I don't know if it's me or my computer but I can't seem to do it...

you got to remember a single phase pot is just that...

treat it as such


for what it's worth....

Edge

[Edge]

opps after reading grooves post I think your talkin more about the load issue... and his answer is much better... I prolly just need some sleep....

Edge

[DerekC]

Topgrove So when you loose a neutral basically u turn whatever the load is into a series circuit is that why the voltage adds like that ?

[DerekC]

Edge are you getting at depending off where you tap off the secondary winding either increases or decreases the amount of windings which works proportionally with the voltage .

This is so interesting hopefully things work out and i can really get my hands on some of this stuff.

[topgroove]

Topgrove So when you loose a neutral basically u turn whatever the load is into a series circuit is that why the voltage adds like that ?Exactly... What edge is trying to tell you is that a secondary coil is simple a winding between X1 and X3. its tapped right in the middle and thats where X2 is.

[MI-Lineman]

Im currently enrolled in a community college line school in the northeast. We have been studying transformers and im a little mind boggled on how the neutral conductor works on the secondary side of a single phase pole transformer. By my understanding the neutral carries the unbalanced load of the two phase conductors and is tapped off the middle of the secondary winding. I checked this by opening my home panel and amp probing my neutral and two phases and it worked out. What happens to the current that flows back to the transformer ?

I think your real question is where does the current go after leavin the house? The source!! You'll here that over and over if ya continue in the electrical trade!!

All neutrals are interconnected or "bonded" and are part of the "system neutral". This system neutral provides a path back to the source for the "return" current! Kind of like the "complete circuit" T.G. was talkin about!

SO SOME DAY WHEN YOU'RE OUT IN THE FIELD WITH A CUSTOMER PISSIN AND MOANIN AT YA CAUSE HIS BILL'S SO HIGH EXPLAIN TO HIM YOU'RE ACTUALLY "RENTIN" THE ELECTRICITY! TO BUY IT WOULD COST A HELL OF A LOT MORE!!:D:D

Just kiddin! Don't do that!!:cool:

[topgroove]

Why NOT? That's friggin Funny!!:D

Now, on a Delta system...Where does the current go...after it leaves the house. And How.

To understand a delta or straight 240 volt circuit, you have to visualize each leg of 120. each sine wave is actualy reversing itself 60 times each second and the two sine waves are exactly 180 degrees apart. a typical 120 volt AC sine wave starts at zero goes up to positive 120 then back to zero and then to negative 120 volts and finally back to zero. because the two hotlegs are exactly 180 degrees out of sync with eachother you'll always have 240 volts potential between them.
Think of AC voltage of not really the electrons moving down a conducter but really electrons sloshing back and forth. The higher a voltage in a AC circuit the higher and lower its sine wave peaks and valleys are.

[pre_apprentice_ID]

Electricity is an amazing thing. It seems so complicated and very interesting, I've got a lot to learn........ I know powerlineman.com will be helpful throughout my schooling.

[MI-Lineman]

THAT's Super "techinical" Groovster, Cool too.:cool:

Bottom line though,

"the current returns to the Source"...thru the delta primarys, Which supply the current.

Yep! One phase at anytime is the return! On a Delta/wye transformer (AC of course) the return current on the sec. neutral can return THROUGH the transformer back on one of the phases!

SOMEONE ASK EDGE HOW HIS BELOVED "MISSION" IS DISTRIBUTED THROUGH THE "BIG SKY" AND THEN BROUGHT OUT OF THE SUBS??:D

MOSTLY DELTA/WYE! Just like our little primary lines to secondary (on a Delta system mind you)?;)

[busman]

To understand a delta or straight 240 volt circuit, you have to visualize each leg of 120. each sine wave is actualy reversing itself 60 times each second and the two sine waves are exactly 180 degrees apart. a typical 120 volt AC sine wave starts at zero goes up to positive 120 then back to zero and then to negative 120 volts and finally back to zero. because the two hotlegs are exactly 180 degrees out of sync with eachother you'll always have 240 volts potential between them.
Think of AC voltage of not really the electrons moving down a conducter but really electrons sloshing back and forth. The higher a voltage in a AC circuit the higher and lower its sine wave peaks and valleys are.

Actually it goes up to 170V and down to -170V. The 120V is the RMS value, not the peak. That's also the reason that gloves and insulation have different ratings at AC and DC. For DC, the RMS and peak are the same number, but not for AC. For AC (sine wave) they are related by the square root of two.

Mark

Mark

[topgroove]

yep that's true...thanks for pointing that out, I was afraid to get too technical.

[rcdallas]

Sumbitch... I've been ponderin delta systems forever now...and I just got my two clicks for loss!!

[DerekC]

Think of AC voltage of not really the electrons moving down a conducter but really electrons sloshing back and forth. .

Thats deep !! Kind of makes sense though because ive seen dryers that are wired with a 10/2 romex thats two hot legs and a grounding conductor. Is that kind of the same theory behind a delta system.


Thanx for the input definitely cleared some things up for me.....


" Renting the electricity " LOL

[MI-Lineman]

Thats deep !! Kind of makes sense though because ive seen dryers that are wired with a 10/2 romex thats two hot legs and a grounding conductor. Is that kind of the same theory behind a delta system.


Thanx for the input definitely cleared some things up for me.....


" Renting the electricity " LOL

Just the tip of the iceburg man! Had an old boy tell me once that ya got "lineman and ya got part changers, learn why you're changin the parts and you'll be a lineman"! Somethin like that anyways? He was right though, you got a chance to learn theory in college so take advantage of it! Some of us learned and in my case, still learnin the hard way!

IT'S ALWAYS BEST TO LEARN EVERY ASPECT OF YOUR JOB!!

GOOD LUCK!!!

[lewy]

I don't think you have to over complicate this, the X2 is connected to ground (or should be) & the current is going back to ground. If you had a balanced load you could get away without a neutral, but we know that the load is not balanced that is why when you loose a neutral some things will not work because they are not getting enough current & somethings will get hot or bright because they are geting to much current.

[wtdoor67]

Lewy's right, don't over complicate it. The ground can be placed in any position. It is sometimes placed on the end of the winding for 2 wire st. lite systems. Then you can have 240 volt st. lites with just the neut. and the end winding. 240 from X3 to X1. I've seen it done that way. If 120 is needed, just tap the X2.

[MI-Lineman]

I don't think you have to over complicate this, the X2 is connected to ground (or should be) & the current is going back to ground. If you had a balanced load you could get away without a neutral, but we know that the load is not balanced that is why when you loose a neutral some things will not work because they are not getting enough current & somethings will get hot or bright because they are geting to much current.

Just answerin the kids question? Maybe you should've jumped in sooner!;)

[wtdoor67]

Ever built a 240 volt straight delta bank; with no mid-tap? I have, quite a few times. I expect most everybody has.

Here's my question. I've always heard and read it, that the 2 legs of lighting found on a typical single phase house pot are 180 degrees apart. I've always took it for granted but I've never seen it drawn out on a schematic or where you could visualize it. I can't see why it wouldn't be 120 degrees. Here's why.

Let's build a 3 pot 240 volt straight delta bank as I've mentioned. Okay, when finished you have 3 phases, that are 240 volts phase to phase. They are electrically 120 degrees apart.

Here's the rub for me. Let us label 2 phases A and B or whatever you wish. These 2 secondary phases are 120 degrees apart. We midtap the pot that is common to phases A and B. They then become 120 volts phase to ground but still 240 volts phase to phase.

According to the 180 degree rule then phases A and B or now 180 degrees apart instead of the former 120 degrees. Someone please explain this.

No need for you to reply Swamp, I know this is beyond your ken.

[Pootnaigle]

Ummm if ya dun that I bleve you would have 240 phase to phase alla way round but yer phase to ground voltage would be 120-120-219 or therebouts.

[T-Man]

I'm on vacation this week but look at page 6 of this pdf. The center tub has the "wild leg" attached to the center of that coil so you can get 120 on two sides for lighting let's say. Not sure if this is what you are looking for "Top"

http://www.jea.com/about/pub/downloads/contractor/OH-2-Transformers.pdf

[Edge]

Ever built a 240 volt straight delta bank; with no mid-tap? I have, quite a few times. I expect most everybody has.

Here's my question. I've always heard and read it, that the 2 legs of lighting found on a typical single phase house pot are 180 degrees apart. I've always took it for granted but I've never seen it drawn out on a schematic or where you could visualize it. I can't see why it wouldn't be 120 degrees. Here's why.

Let's build a 3 pot 240 volt straight delta bank as I've mentioned. Okay, when finished you have 3 phases, that are 240 volts phase to phase. They are electrically 120 degrees apart.

Here's the rub for me. Let us label 2 phases A and B or whatever you wish. These 2 secondary phases are 120 degrees apart. We midtap the pot that is common to phases A and B. They then become 120 volts phase to ground but still 240 volts phase to phase.

According to the 180 degree rule then phases A and B or now 180 degrees apart instead of the former 120 degrees. Someone please explain this.

No need for you to reply Swamp, I know this is beyond your ken.

you center taped the coil... think of it as just one pot now... a and b now have a tap to dirt makeing them 180degrees apart...oppisite ends of the same coil... a and c & b and c have nothing tappin them to dirt so they remain in the triangle being 120... it's where geometry meets linework... funky for sure but try drawing it an you'll get in... draw your delta then the tap and you'lll prolly do what I did... "ahhh shit thats so simple WTF"

glad to have you back 'door... was missing banging around the "technical" side of the trade...

for what it's worth...

Edge

[wtdoor67]

That don't explain it to me.

Take a typical Wye/Delta 3 pot bank as typically built. Build one with only a straight delta secondary. I've built such. Most have. Okay you have 3 secondary phases coming off of each corner of the delta. Now at this moment these 3 secondary phases are 120 degrees apart. That's easy to see.

Here's what I don't see. Midtap one of the pots for lighting. Suddenly, according to what I've always read, the two phases jointly feeding from the lighting pot, that were 120 degrees apart become 180 degrees apart. Don't compute for me.

I have paralled single phase lighting pots hanging alone with the lighting pot hung in a bank so I know the lighting will go together.

[topgroove]

try this,,, grab a 120 volt streetlight transformer out of the trash bin. the primary coil (120volt side) is almost always good. use a sawzall and cut the secondary side out. Take some insulated wire and wrap twenty or so coils around the core. take a voltage reading and tell me what you get. Now take it apart and wrap ten loops around the core and make a loop and wrap ten more loops around the core, skin the loop in the middle. You've just made an A BC D secondary coil. Take a voltage reading and you'll see between A and BC and BC and D are exactly the same. Add them up and you'll get the exact same voltage between A and D. Its a simple coil of wire with an induced voltage from the primary. nothing magical. simply turns ratio. The number of coils and the resistance of the wire determins your secondary voltage.

[wtdoor67]

Draw a closed delta voltage triangle. From each point of the triangle emanates a phase. These lines drawn from each point are 120 degrees apart. This seems logical to me. If this closed delta drawing is made up of typical house pots, then you have an ungrounded "straight" delta secondary that reads 240 volts in all three positions phase to phase.

Okay, simple so far. Now center tap the middle point of a line that joins 2 points of this triangle. This is of course the neutral etc. point that everyone is familiar with.

Why does this separation that was 120 degrees, suddenly become 180 degrees? Why isn't the separation from neutral to each respective lighting phase 60 degrees and the separation from lighting phase to lighting phase remain 120 degrees as it was before you mid-tapped it?

[MI-Lineman]

I don't think you have to over complicate this, the X2 is connected to ground (or should be) & the current is going back to ground. If you had a balanced load you could get away without a neutral, but we know that the load is not balanced that is why when you loose a neutral some things will not work because they are not getting enough current & somethings will get hot or bright because they are geting to much current.

WOW! Now I know what Lewy's talkin about?:D

[lewy]

Draw a closed delta voltage triangle. From each point of the triangle emanates a phase. These lines drawn from each point are 120 degrees apart. This seems logical to me. If this closed delta drawing is made up of typical house pots, then you have an ungrounded "straight" delta secondary that reads 240 volts in all three positions phase to phase.

Okay, simple so far. Now center tap the middle point of a line that joins 2 points of this triangle. This is of course the neutral etc. point that everyone is familiar with.

Why does this separation that was 120 degrees, suddenly become 180 degrees? Why isn't the separation from neutral to each respective lighting phase 60 degrees and the separation from lighting phase to lighting phase remain 120 degrees as it was before you mid-tapped it?

I think you just answered your own question.

[Brooks]

Draw a closed delta voltage triangle. From each point of the triangle emanates a phase. These lines drawn from each point are 120 degrees apart. This seems logical to me. If this closed delta drawing is made up of typical house pots, then you have an ungrounded "straight" delta secondary that reads 240 volts in all three positions phase to phase.

Okay, simple so far. Now center tap the middle point of a line that joins 2 points of this triangle. This is of course the neutral etc. point that everyone is familiar with.

Why does this separation that was 120 degrees, suddenly become 180 degrees? Why isn't the separation from neutral to each respective lighting phase 60 degrees and the separation from lighting phase to lighting phase remain 120 degrees as it was before you mid-tapped it?

Stop thinking phase to phase when dealing with single phase installations. Think L1 and L2, Hot leg, hot leg, neutral. Not A phase, B phase, C phase. They are not the same type measurement.

In a delta with a mid tap on one phase, you are creating a single phase circuit within the three phase delta.

When you mid tap one side, you are not changing the angular relationship. You are measuring across the coil on the same phase it is linear not angular. Stop thinking phases as in a three phase sytem. You are working on one phase and measuring the length of the leg for 240 or 480 and half that on either side of the midpoint.

When you measure from the midpoint neutral tap to the high leg, you have split the delta into two right triangles. This is an angular measurement hence the 208 or 416 depending on your application.

[topgroove]

Stop thinking phase to phase when dealing with single phase installations. Think L1 and L2, Hot leg, hot leg, neutral. Not A phase, B phase, C phase. They are not the same type measurement.

In a delta with a mid tap on one phase, you are creating a single phase circuit within the three phase delta.

When you mid tap one side, you are not changing the angular relationship. You are measuring across the coil on the same phase it is linear not angular. Stop thinking phases as in a three phase sytem. You are working on one phase and measuring the length of the leg for 240 or 480 and half that on either side of the midpoint.

When you measure from the midpoint neutral tap to the high leg, you have split the delta into two right triangles. This is an angular measurement hence the 208 or 416 depending on your application.Again...you are absoultly correct. They are only out of phase with respect to eachother.
So why do people say that the two 120 volt legs feeding our houses are 180 degrees out of phase? Well, technically, they’re not; it really depends on how you look at things; it’s a matter of perspective. For instance: when we ride in a vehicle, we see things going by us as we look out the window. Technically, that’s not true. In reality, WE are going by the things we see. Some people will try to “prove” that the power legs are 180 degrees out of phase by connecting the common probe of an oscilloscope to the neutral and then measuring each power leg. What they get is 2 sine waves 180 degrees out of phase from each other. But, what they have done is reversed the order of the probes. If you measure a DC battery and get -1.5 volts, is the battery actually a negative 1.5 volt battery? No, we simply reversed the probes and therefore our perspective.

Another example would be to place 2 D-Cell batteries in series with each other (the positive end of one touching the negative end of the other). If we place our negative probe in the middle (at the connection point between the 2 batteries), we will measure +1.5 volts if we place the positive probe on the positive end of the batteries, and -1.5 volts if we place the positive probe on the negative end of the batteries. If we measure across both of them, we get 3.0 volts. The 2 batteries APPEAR to be “out of phase” with each other, when in fact, we are just misinterpreting our measurements.

In either case, if the 2 sources WERE 180 degrees out of phase from one another, they would cancel each other out and we would measure 0 volts!

[topgroove]

The simplest type of transformer is made up of two coils wound around a common core: the primary coil (which is typically the high voltage coil) and the secondary coil (typically the low voltage coil). Each coil has a wire connected to each end. If you connect a voltage source across the primary coil, a voltage will be induced on the secondary coil that is a fraction of the input voltage (on the primary coil) which is determined by the ratio of the number of turns of wire in the primary coil to the number of turns of wire in the secondary coil. A single simple transformer cannot shift the sine wave, therefore the sine wave measured at the secondary will be exactly in phase with the sine wave measured at the primary, only one will have an amplitude larger than the other.

This type of transformer is considered to be a single-phase transformer; it uses one voltage potential to produce another. You may have seen transformers with a single primary coil, but multiple secondary coils. These are still considered to be single-phase transformers; the voltage produced by each secondary coil (the secondary voltage) will be in phase with the primary voltage and, therefore, to each other. Since everything is in phase with each other, we are talking about one phase (single-phase).

How three-phase power is originally produced, is determined by how the generator or turbine producing it is built I won’t go into that here, since we are only concerned with how we get single-phase from a three-phase source.

Any three-phase voltage that you are likely to work with originates from the secondary coils of some type of three-phase transformer. A three-phase transformer is basically made up of 3 single-phase transformers. (For simplicity, I’ll stick with delta transformers, since they tend to be easier to understand.) The coils of a delta transformer are connected to each other in a series loop. (The right side of one transformer is connected to the left side of the next. The right side of the 3rd transformer is connected to the left side of the 1st.) Each transformer induces a different sine wave on its secondary coil that is in phase with the sine wave on its primary coil. There is no voltage or phase-shifting happening; rather the voltage is simple being reduced.

When you measure three-phase voltage line-to-line, you are connecting your voltmeter to 2 of the 3 wires; you are actually measuring the voltage across the secondary winding of a single transformer. Therefore, you are measuring only one phase. The same goes with the transformer supplying your house; it has a single primary winding and a single secondary winding. The primary is connected to only one phase (via 2 wires) and produces only one phase which measures 240 VAC (there is only one core).

How then do we get 120 VAC if we’re receiving 240 VAC? Coils work somewhat like potentiometers, when it comes to measure the voltage across them. Put the probe of a voltmeter across the entire coil and you’ll read the entire voltage being delivered by the coil. If you had access to any point on the coil (which we typically don’t), you could leave one of your probes (let’s say, the black one) on the end of the coil and move the red probe to some other intermediate part of the coil. If we set the red coil 2/3 of the way from the black one (leaving the black one on the end), we would read 2/3 of the voltage. If we measure the voltage across half of the coil, we will get half the voltage. Why this works is obvious, if you think about it: by measuring a smaller portion of the coil, we are actually measuring fewer turns of wire, which is like having a transformer with a different turns ratio. So it doesn’t really matter where we put our probes; we can get 120 VAC by placing one probe at some random point on the coil, and the other probe on the coil at a point that the number of turns of wire produces 120 VAC.

[wtdoor67]

Of course I'm not talking about angular displacement, which some seem to be talking about.

All I'm talking about is degrees of separation between phases. A different thing.

[topgroove]

Of course I'm not talking about angular displacement, which some seem to be talking about.

All I'm talking about is degrees of separation between phases. A different thing. I hear what your saying wtdoor. people seam to get all riled up over symatics. Earlier I tried to answer this guys post with a plain and simple answer. Unfortunatly its rarely plain and never simple.

[T-Man]

Does this help?

http://www.allaboutcircuits.com/vol_2/chpt_10/6.html

Three phase delta system has nothing to do with a single phase transformer. you need single phase transformers to make a three phase delta.

[wtdoor67]

However it's always been a question in my mind. A person can do a lifetime of this work and never need to know this. I always have a curiosity though.

Now T-Man. 3 single phase transformers sitting side by side, and hooked in a Delta configuration do create a Delta circuit. There are 3 phases 120 degrees apart. If the rating of these transformers are 120/240, 240/480 are anything for that matter they create a bonafide, 3 phase Delta circuit. These are, some call a "straight" Delta circuit. At this point they can be used, if hooked directly, only to a 3 phase device. This is an ungrounded circuit. 120 degrees apart.

If these transformers have a center tap capability and you then do this to only one, then of course you have created a single phase lighting circuit. In the case of 120/240 pots of course you now have a lighting or house circuit. Whatever you wish to call it.

This is my point. 2 of the phases that were formerly 120 degrees apart, by simply midtapping them become 180 degrees apart. At least that's what I've read. Don't seem logical.

[topgroove]

they are only 180 degrees apart in relation to eachother. they both share the same coil but because of the resistance in the secondary coil they are at a different voltage potential. The sine wave of the primary coil is the same sine wave of the secondary coil only the primary coil will have a much greater amplitude.

[T-Man]

I need my chalk and board you guys are Driving me crazy. . . .it's a short drive but none the less a drive. . . .:confused::D.LOL

[PSE Lineman]

3 phases of primary, 3 transformers= 120 degrees apart!
2 phases of secondary, 1 transformer=180 degrees apart!
Am I missing something?

[Brooks]

There are multiple circuits within the delta. They are both ends of the same coil.

Think about a line with a point in the middle and facing east/west. If you head from the midpoint east then do a Starsky and Hutch(a 180) and head to the other end...

You can do this on a wye wye bank to serve 120/208 and 120/240 from the same bank. I haven't seen this outside of a local service inside of a substation but it could be done if the loading of the bank was downgraded accordingly.

[topgroove]

3 phases of primary, 3 transformers= 120 degrees apart!
2 phases of secondary, 1 transformer=180 degrees apart!
Am I missing something?No not at all... its a matter of symatics or how you look at it. Sure you could say they're 180 degrees apart, but thats in relation to eachother. Technically the sine wave of the primary is in sync with the 240 volt secondary. Only the amplitude of the primary coil sine wave is much higher. I know it sounds confusing, I think I explained it better on the previous page.

[Brooks]

Topgroove is correct.

[topgroove]

Topgroove is correct.Thanks Brooks! I know I'm terrible at explaining things. :o

[Edge]

Stop thinking phase to phase when dealing with single phase installations. Think L1 and L2, Hot leg, hot leg, neutral. Not A phase, B phase, C phase. They are not the same type measurement.

In a delta with a mid tap on one phase, you are creating a single phase circuit within the three phase delta.

When you mid tap one side, you are not changing the angular relationship. You are measuring across the coil on the same phase it is linear not angular. Stop thinking phases as in a three phase sytem. You are working on one phase and measuring the length of the leg for 240 or 480 and half that on either side of the midpoint.

When you measure from the midpoint neutral tap to the high leg, you have split the delta into two right triangles. This is an angular measurement hence the 208 or 416 depending on your application.


yeah Brooks thats what I was trying to say in my post you did a MUCH better job...

and Groove killer info man you nailed that shit...

T-Man thinks for the links good stuff there man...

for what it's worth...

Edge

[topgroove]

yeah Brooks thats what I was trying to say in my post you did a MUCH better job...

and Groove killer info man you nailed that shit...

T-Man thinks for the links good stuff there man...

for what it's worth...

EdgeThanks Edge... Thats why I love this site!
Lineman helping lineman. All that political crap gets boring. I'll take a conversation on electrical theory anyday!:)

[T-Man]

Ditto Groove

Your welcome Edge

[DerekC]

Man i have a lot to learn !! It seems like my question has taken me on a journey. This website is a unbelievable source of info. You can only learn so much in he class room. Thats why its great to pay attention to the guys on this site and ask questions . Im just trying to learn the lingo and trying to pick up as much as possible so if i do get a job i can have a half way intelligent conversation with the guys. I was wondering what sites or books you guys may have read or visited to learn the different transformer configurations / banking or is this stuff u learn in the field. Also wondering if you think i should be focused on other things seeing im just trying to get in the trade?

I think im going to change my name to derekc the wannabe !!!

[T-Man]

DerekC - wannabe,

It's good you want to learn all this good stuff, and want to carry on a conversation with linefolk, but be careful that when you talk the talk and haven't walked the walk you will get figured out by real linemen in an instant. Lean, listen and try to get better each day. don't talk over your head because a JL will see thru you just like they can tell if you can climb by the fifth step up the pole. . . Good Luck and work safe.

I like this book for starters. It isn't cheap but it's timeless info.

Electrical Essentials for Powerline Workers (Paperback)
by Wayne Van Soelen

Stay interested if this is what you want and learn all you can because when the hiring starts the best will get jobs first, there will be big competition when that opens up.

T

[topgroove]

DerekC - wannabe,

It's good you want to learn all this good stuff, and want to carry on a conversation with linefolk, but be careful that when you talk the talk and haven't walked the walk you will get figured out by real linemen in an instant. Lean, listen and try to get better each day. don't talk over your head because a JL will see thru you just like they can tell if you can climb by the fifth step up the pole. . . Good Luck and work safe.

I like this book for starters. It isn't cheap but it's timeless info.

Electrical Essentials for Powerline Workers (Paperback)
by Wayne Van Soelen

Stay interested if this is what you want and learn all you can because when the hiring starts the best will get jobs first, there will be big competition when that opens up.

T Great advise T-Man ! I've found the apprentices that don't say $hit even with a mouth full and listen to everything they're told have the easiest time of it. At work You really shouldn't talk about electrical theory with your journeyman or foreman. Keep it in the classroom or here on the forum.

[lewy]

Great advise T-Man ! I've found the apprentices that don't say $hit even with a mouth full and listen to everything they're told have the easiest time of it. At work You really shouldn't talk about electrical theory with your journeyman or foreman. Keep it in the classroom or here on the forum.

Top I have to disagree regarding an apprentice talking theory with me, when we are in the truck he can ask me any thing he wants & tell me what he knows. I wont debate with him in the air.

[topgroove]

you're a good man lewy! I know what you mean, I love to kick around electrical theory too. you have to admitt there's a bunch of wingnuts who love to beat up on apprentices in our trade.

[T-Man]

Like Top said in the classroom and here and even in the cab of the truck ok, but I've seen guys talk all about how they tamed the world years ago and they are still wet behind the ears. . . so I was giving that young buck a pointer or two on how to get along in this business. I want them to be smart not smart a$$e$.

[climbsomemore]

any 3 wire circuit that has a neutral works like this.

The 3rd "neutral" wire is responsible for the return of any unbalance amperage to the source.

120/240v house service... if leg A carries 30 amps and leg B has 20 amps of load the neutral carries the unbalance difference-10 amps.

If you balance the load A-50 b-50 there is no unbalanced current to return... In fact-all the current travels in series-through every device that is turned on inside that house.... sort of. O amps is read on the neutral at that time

In theory what happens is that the current ...curent is seen as moving through the transformer winding in the direction of the "hot bushings" (x1 and x3.. (the neutral connect to the middle of said winding or x2)
If the current was actually moving through the house load as a true series circuit.. many of the devices would drop voltage based on the resistance contained in the device itself (ohms). The 120 volts need a grounded reference to work correctly (they need 120 volts of potential to work correctly-it has to see ground) if they were is series we would see the same damage as we would if we "lost the neutral"-- some stuff (like your low resistance computer or TV) would get too high a voltage... and stuff like your hairdryer (high resistance) would not drop enough... Expensive stuff burns up...cheap stuff survives.

You get a zero reading on a balanced neutral because the neutral current form leg A...actually travels past the current from Leg B--- in opposite directions. As a vector problem... if the return current is equal they would cancel each other out... and the ampmeter reads '0".