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Default expanation of 3 phaze power

Jim Wilkins wrote:

120V single phase is hot to neutral, 240V is hot to hot.


Did he write that he's using 240V?


Nick
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Default expanation of 3 phaze power

On Feb 18, 1:33*pm, Nick Mueller wrote:
Jim Wilkins wrote:
120V single phase is hot to neutral, 240V is hot to hot.


Did he write that he's using 240V?

Nick


Industrial wiring practice here is to tag the incoming 3-phase wires
L1, L2, L3, then prefix them with increasing numbers as they pass
through switches, breakers, etc.

Single phase AC is likely to be marked Hot, Neutral and Ground (ACH,
ACN, GND, z.B.) although company drafting standards vary.

Jim Wilkins
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Default expanation of 3 phaze power


"Jim Wilkins" wrote in message
...
On Feb 18, 1:33 pm, Nick Mueller wrote:
Jim Wilkins wrote:
120V single phase is hot to neutral, 240V is hot to hot.


Did he write that he's using 240V?

Nick


Industrial wiring practice here is to tag the incoming 3-phase wires
L1, L2, L3, then prefix them with increasing numbers as they pass
through switches, breakers, etc.

Single phase AC is likely to be marked Hot, Neutral and Ground (ACH,
ACN, GND, z.B.) although company drafting standards vary.

Jim Wilkins

Hi Jim

First, I agree with your posts. Is it likely that there any country
where a 3 phase motor requires it's power to be connected to the neutral? I
dont mean safety ground. I refer to the input voltage to which *any* 3
phase motor is connected so it can deliver power to a load.

Jerry


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Default expanation of 3 phaze power

On Feb 18, 4:52*pm, "Jerry" wrote:
"Jim Wilkins" wrote in message

...
On Feb 18, 1:33 pm, Nick Mueller wrote:

Jim Wilkins wrote:
120V single phase is hot to neutral, 240V is hot to hot.


Did he write that he's using 240V?


Nick


Industrial wiring practice here is to tag the incoming 3-phase wires
L1, L2, L3, then prefix them with increasing numbers as they pass
through switches, breakers, etc.

Single phase AC is likely to be marked Hot, Neutral and Ground (ACH,
ACN, GND, z.B.) although company drafting standards vary.

Jim Wilkins

* Hi Jim

* First, I agree with your posts. * * Is it likely that there any country
where a 3 phase motor requires it's power to be connected to the neutral? *I
dont mean safety ground. * I refer to the input voltage to which *any* 3
phase motor is connected so it can deliver power to a load.

* * * * * * * * * Jerry


3 phase wye has a neutral connection, 3 phase delta has only hot
leads.

Jim Wilkins
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Default expanation of 3 phaze power

Jerry wrote:

Is it likely that there any country
where a 3 phase motor requires it's power to be connected to the neutral?
I dont mean safety ground. Â* I refer to the input voltage to which *any* 3
phase motor is connected so it can deliver power to a load.


You're starting to mix up things.
1 phase power has "hot" (L1, L2, or L3 you never know) and N (=neutral).
Three phase has L1, L2, L3 and N (+ PE for one and 3 phase). You *could*
connect N to the common point (center of star) if the motor is wired in
star, but there absolutely is no need for as the sum in the common point is
always 0 V (- thus N).


Nick
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Default expanation of 3 phaze power


"Jim Wilkins" wrote in message
...
On Feb 18, 4:52 pm, "Jerry" wrote:
"Jim Wilkins" wrote in message

...
On Feb 18, 1:33 pm, Nick Mueller wrote:

Jim Wilkins wrote:
120V single phase is hot to neutral, 240V is hot to hot.


Did he write that he's using 240V?


Nick


Industrial wiring practice here is to tag the incoming 3-phase wires
L1, L2, L3, then prefix them with increasing numbers as they pass
through switches, breakers, etc.

Single phase AC is likely to be marked Hot, Neutral and Ground (ACH,
ACN, GND, z.B.) although company drafting standards vary.

Jim Wilkins

Hi Jim

First, I agree with your posts. Is it likely that there any country
where a 3 phase motor requires it's power to be connected to the neutral?
I
dont mean safety ground. I refer to the input voltage to which *any* 3
phase motor is connected so it can deliver power to a load.

Jerry


3 phase wye has a neutral connection, 3 phase delta has only hot
leads.

Jim Wilkins

Hi Jim

I realize that the 3 phase supplied by the power company can include a Y
neutral. My curiosity is related to the use of the Y neutral for supplying
power to a 3 phase motor. I havent ben able to figure out where the Y
neutral can be of benefit for supplying power to a 3 phase motor.

Jerry


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Default expanation of 3 phaze power

On Tue, 19 Feb 2008 00:55:51 +0100, Nick Mueller
wrote:

Jerry wrote:

Is it likely that there any country
where a 3 phase motor requires it's power to be connected to the neutral?
I dont mean safety ground. * I refer to the input voltage to which *any* 3
phase motor is connected so it can deliver power to a load.


You're starting to mix up things.
1 phase power has "hot" (L1, L2, or L3 you never know) and N (=neutral).


Here in the US that's true for 120V single phase, not 240V single
phase supplies.

Three phase has L1, L2, L3 and N (+ PE for one and 3 phase).


Not for 3-phase 3-wire systems.

This page shows the connections found in the US, including a couple
rarely used. The first is the connection used in single family
residences. Ungrounded delta and grounded wye are the most common in
large industrial installations, at least here in New England.
http://www.bmillerengineering.com/elecsys.htm

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Default expanation of 3 phaze power

There are as many ways to connect 3 phase as 3^3. Some of the statements
here are to be taken as general statements, not all cases.

Often the D has "center" taps and are used as speed controls for motors
or in the cases of some home sites, the center is center and the two legs
are 208 either side or a like number. Homes have ranged from 100v to 130v
in my lifetime and the wire wasn't replaced, nor were the transformers. To many
to replace. The center was grounded at the pole and brought to the house.

Sometimes an AC ground is generated by use of capacitors forming a central node.

Motors are complex indeed. e.g. A three-phase Four pole, series Star connection.
(a.k.a. a three phase wye with each leg having 4 windings(phased).
Contrast that with a Four-pole, two-parallel star connection with six jumpers.
Three branches, each containing 4 windings, that is two windings in series and
that series set is in parallel with another just like it.

In complex motors there are up to 12 phases in 'twisted stars'. Phase shifted
windings of various voltages.

Electric stoves are 'duck soup' in comparison.

Martin

Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
TSRA, Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Charter Founder
IHMSA and NRA Metallic Silhouette maker & member.
http://lufkinced.com/


Jerry wrote:
"Jim Wilkins" wrote in message
...
On Feb 18, 4:52 pm, "Jerry" wrote:
"Jim Wilkins" wrote in message

...
On Feb 18, 1:33 pm, Nick Mueller wrote:

Jim Wilkins wrote:
120V single phase is hot to neutral, 240V is hot to hot.
Did he write that he's using 240V?
Nick

Industrial wiring practice here is to tag the incoming 3-phase wires
L1, L2, L3, then prefix them with increasing numbers as they pass
through switches, breakers, etc.

Single phase AC is likely to be marked Hot, Neutral and Ground (ACH,
ACN, GND, z.B.) although company drafting standards vary.

Jim Wilkins

Hi Jim

First, I agree with your posts. Is it likely that there any country
where a 3 phase motor requires it's power to be connected to the neutral?
I
dont mean safety ground. I refer to the input voltage to which *any* 3
phase motor is connected so it can deliver power to a load.

Jerry


3 phase wye has a neutral connection, 3 phase delta has only hot
leads.

Jim Wilkins

Hi Jim

I realize that the 3 phase supplied by the power company can include a Y
neutral. My curiosity is related to the use of the Y neutral for supplying
power to a 3 phase motor. I havent ben able to figure out where the Y
neutral can be of benefit for supplying power to a 3 phase motor.

Jerry


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Default expanation of 3 phaze power

Ned Simmons wrote:

Here in the US that's true for 120V single phase, not 240V single
phase supplies.


Singel phase 120V, two phase 240V.

Three phase has L1, L2, L3 and N (+ PE for one and 3 phase).


Not for 3-phase 3-wire systems.


Is it any wonder? :-)


Nick
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Default expanation of 3 phaze power

Nick Mueller wrote:
Ned Simmons wrote:


Here in the US that's true for 120V single phase, not 240V single
phase supplies.


Singel phase 120V, two phase 240V.


Nope, single phase 120V, single phase 240V

This is 2-phase power. 4 wires.

http://www.3phasepower.org/2phasesystems.htm
http://en.wikipedia.org/wiki/Two_phase

And at least as of a few years ago, they were still supplying 2-phase
4-wire power about 40 miles from where I live in PA.




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On Feb 19, 3:53*am, Nick Mueller wrote:
...
Singel phase 120V, two phase 240V.

...
Nick


You could logically call it two phase since they are 180 degrees
apart, but the term is used instead for Tesla's original system of 90
degree phase shift. He was given the challenge of reducing brush wear
on DC motors and had the inspiration that a sine plus a cosine at
right angles gives a smoothly rotating vector, in other words a
rotating magnetic field to pull the armature around with no brushes
needed.

Modern single phase motors create a temporary second shifted phase
that they need to start turning with an extra start winding with
series resistance or capacitance to delay the current. The click you
hear when the motor starts or stops is a centrifugal switch in series
with the start winding.

Jim Wilkins
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Default expanation of 3 phaze power

On Feb 19, 7:33 am, Jim Wilkins wrote:
On Feb 19, 3:53 am, Nick Mueller wrote:
...

Singel phase 120V, two phase 240V.

...
Nick


You could logically call it two phase since they are 180 degrees
apart, but the term is used instead for Tesla's original system of 90
degree phase shift. He was given the challenge of reducing brush wear
on DC motors and had the inspiration that a sine plus a cosine at
right angles gives a smoothly rotating vector, in other words a
rotating magnetic field to pull the armature around with no brushes
needed.

Modern single phase motors create a temporary second shifted phase
that they need to start turning with an extra start winding with
series resistance or capacitance to delay the current. The click you
hear when the motor starts or stops is a centrifugal switch in series
with the start winding.

Jim Wilkins


I didnt know about the original two phase but DAMN thats elegant
inserting the right phase shift makes the stator drag the rotor
around.

Scares you that that is a 100 year old idea
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Default expanation of 3 phaze power

On 2008-02-18, Nick Mueller wrote:
jk wrote:

No this is where your analysis falls apart.

A single phase supply is TWO count 'em TWO wires, i.e. L1 AND L2


A single phase is one phase and neutral.


That depends on where you are located. In the USA, 240 V single
phase has a grounded center tap, with two 120 V lines 180 degrees out of
phase -- that is while one is going positive, the other is going
negative. So -- L1 and L2 *are* single phase in the US.

Or for that matter, power fed from any two of a three-phase feed
is single phase as long as you aren't referencing anything to neutral,
which would get you lower voltages if the feed is Wye, or indeterminate
voltages if the feed is ungrounded delta. (Some delta feeds in the US
have one corner grounded, and some have a center tap of one phase
grounded.)

In the UK, 240 VAC has one side grounded -- but does not have a
lot of equipment built for 120 VAC to run (unless someone brought a lot
of stuff from the US when they moved to the UK.) I presume that Germany
is similar?

Enjoy,
DoN.

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Default expanation of 3 phaze power

Nick Mueller wrote:

jk wrote:

No this is where your analysis falls apart.

A single phase supply is TWO count 'em TWO wires, i.e. L1 AND L2


A single phase is one phase and neutral.


Nick

Only if you have a 4 wire wye connected motor. Fairly Rare Hell damn
rare.

And I can feed you single phase power from a system with NO neutral.


jk
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Default expanation of 3 phaze power

Doesn't matter, the 240 is still single phase power.

Nick Mueller wrote:

Jim Wilkins wrote:

120V single phase is hot to neutral, 240V is hot to hot.


Did he write that he's using 240V?


Nick


jk
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