3 phase power question

[JEDI]

1) Why is common for the voltage to be 480v in commercial buildings in the US? Is that the standard? (Just like 120v is standard for residential?)

2a) In a low voltage 3phase panel (black/red/blue) <Wye is secondary side on transformer>:
single pole breaker = 120v
double pole = 208v
triple pole = ???

2b) In a high voltage 3phase panel (brown/orange/yellow) <Delta is secondary side on transformer?>:
single pole = 277v
double pole = 480v
triple pole = ???


edit:
reworded question #1 to clarify

 

[BassBomb]

i believe 480v relates to ANSI standard that is why

i know for my internship (I was on mechanical side) the electrical guys had to design the ANSI MCC's based off 480V@60hz while the IEC standard was something like 400V@50

 

[bobdole369]

(Just like 120v is standard for residential?)

Actually 220V is the standard at the breaker box in the USA - we use half of it for receptacles. 220V in the receptacles is standard most of the rest of the world.

2a) In a low voltage 3phase panel (black/red/blue) <Wye is secondary side on transformer>:
single pole breaker = 120v
double pole = 208v
triple pole = ???

2b) In a high voltage 3phase panel (brown/orange/yellow) <Delta is secondary side on transformer>:
single pole = 277v
double pole = 480v
triple pole = ???

do your own homework. All of that is fairly elementary, and easy to google. I hope you aren't wiring anything up of mine, you seem to miss a basic component.

 

[Modelworks]

Why is it common ?
motors

 

[SparkyJJO]

Why is it common ?
motors

Exactly. 3 phase motors are quite efficient. Single phase motors are horribly inefficient.

 

[JohnCU]

3 phase power = constant power

 

[JEDI]

Exactly. 3 phase motors are quite efficient. Single phase motors are horribly inefficient.

i'm not asking why is 3phase common. i'm asking why is it 480v? and apparently it's because it's a standard in the US?

 

[Colt45]

Why is 120V standard for household stuff? It's just how it is.

120 phase to neutral -> 208v phase to phase.
277 -> 480
347 -> 600

 

[Sea Moose]

In Australia

when you test with your voltmeter from earth to red,white or blue wire you get around 230 to 240volts

if you test across the phases with your voltmeter from red to white or from white to blue or blue to red you will get around 415v to 420volts


I think that 3 phase motors are more efficient especially if used with a variable speed drive.

 

[TheSiege]

1) Why is common for the voltage to be 480v in commercial buildings in the US? Is that the standard? (Just like 120v is standard for residential?)

2a) In a low voltage 3phase panel (black/red/blue) <Wye is secondary side on transformer>:
single pole breaker = 120v
double pole = 208v
triple pole = ???

2b) In a high voltage 3phase panel (brown/orange/yellow) <Delta is secondary side on transformer?>:
single pole = 277v
double pole = 480v
triple pole = ???


edit:
reworded question #1 to clarify

2a) A 3-pole breaker would be 3 phase 120. plain and simple.
2b) Would be 3 phase 480.

Look at a wye and a delta transformer and it makes more sense, like the other poster said, phase to ground/neutral produce a voltage and phase to phase creates a different voltage, the rest is just single or 3 phase

<--Electrician

 

[Gillbot]

480 has been the common voltage for years, but IMHO it's giving way to 4160 drops. Depending on the facility of course. Some are higher, some still opt for the typical 480v.

 

[MichaelD]

Having lived in Europe for quite some time I can say that 220v receptacle power kicks the snot out of our 110v power. You can plug an electric oven or electric dryer straight into a normal outlet. NO special plug, wiring, expensive rejiggering from an electrician required! Also, cords for appliances just don't get hot at all like they do w/110v appliances. Twice the voltage, half the amperage FTW.

The US should switch.

 

[Rubycon]

Volts to ground x 1.73 = volts phase to phase.

Phases are 120 degrees apart x 3 = 360 degrees = 1 rotation of generator.

Easy as pie!

 

[JohnCU]

Volts to ground x 1.73 = volts phase to phase.

Phases are 120 degrees apart x 3 = 360 degrees = 1 rotation of generator.

Easy as pi!

fixed

 

[Rubycon]

fixed

The square root of pie is three.

 

[Modelworks]

Having lived in Europe for quite some time I can say that 220v receptacle power kicks the snot out of our 110v power. You can plug an electric oven or electric dryer straight into a normal outlet. NO special plug, wiring, expensive rejiggering from an electrician required! Also, cords for appliances just don't get hot at all like they do w/110v appliances. Twice the voltage, half the amperage FTW.

The US should switch.

How many people are walking around with ovens ? no need for 220VAC on every outlet. If the cord gets hot then it isn't the right cord for the application. Europe is still using the antiquated 50hz power, they need to move up to 60hz. Just be glad DC power never became the standard.

 

[Rubycon]

How many people are walking around with ovens ? no need for 220VAC on every outlet. If the cord gets hot then it isn't the right cord for the application. Europe is still using the antiquated 50hz power, they need to move up to 60hz. Just be glad DC power never became the standard.

50Hz makes awesome arc reports though.

 

[JohnCU]

50Hz makes awesome arc reports though.

why would 10 hz make that much difference?

 

[Rubycon]

why would 10 hz make that much difference?

It's a deeper pitch closer to a sharp note and carries better.

 

[JohnCU]

It's a deeper pitch closer to a sharp note and carries better.

interesting. i usually don't think of electrical signals in musical terms.

 

[Rubycon]

interesting. i usually don't think of electrical signals in musical terms.

Well sound reproduction is entirely dependent on manipulation of sinusoidal electromotive force. Extremely minute forces can influence/change such flows along the signal path - some beneficial some detrimental (1% vs. 99% typical respective ratio in real life!) - so the challenge for faithful reproduction of a performance is very real.

Additionally the ability of the ear to discern changes is many many times higher in order of precision than the eye so listening to your machinery/gear often provides better clues as to what may be changing, etc.

 

[JohnCU]

Well sound reproduction is entirely dependent on manipulation of sinusoidal electromotive force. Extremely minute forces can influence/change such flows along the signal path - some beneficial some detrimental (1% vs. 99% typical respective ratio in real life!) - so the challenge for faithful reproduction of a performance is very real.

Additionally the ability of the ear to discern changes is many many times higher in order of precision than the eye so listening to your machinery/gear often provides better clues as to what may be changing, etc.

have my babies rubycon :wub:

 

[Sea Moose]

have my babies rubycon :wub:

Lol


It hot when she talks dirty :wub:

 

[Rubycon]

have my babies rubycon :wub:

How many do you have?

Lol


It hot when she talks dirty :wub:

Sounds like an AC problem. Turn your 'stat as far as it will go to the left! :hmm:

 

[Sea Moose]

Sounds like an AC problem. Turn your 'stat as far as it will go to the left! :hmm:

There is a lot of love in this thread :wub: - I admire intelligent women. And rubycon is one of the nicest gals on atot! (sorry to the other 3)