Neutral Question

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mivey said:
Kind of the point. I was speaking of the neutral point shift with unbalance.

With a balanced load, the equilibrium point and X0 are the same. Lift the neutral wire from X0 and it will stay at the same voltage as X0.

With an unbalanced load, say two 120 volt loads, lift the neutral wire from X0 and the neutral point will shift to half way between X1 and X2 which is 60 volts from X0.
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Would a running 5 ohm heater L1-N and a 10 ohm heater L2-N produce this 60 volts N to open N?
 
jumper said:
You need to explain the position of said UK spark since most systems in UK utilize a grounded wye with a center point neutral.

Resi is one phase and a noodle at ~215-230V.

So I am unclear on the issue: they use a neutral.
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That's how you get the 230V - obviously...
 
Had multiple posts marked for reply - kind of gave up though, some of what I was going to say already been addressed.

But this:

Ingenieur said:
freakin' 10 F here

down to 3 by 7 AM
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Is not cold, (to me anymore) would have loved to see that temp last night. High temp yesterday never went above zero to my knowledge. Overnight forecast was for -18 low, haven't yet heard what it actually reached.
 
mbrooke said:
Always do- yes- the second one. Current can not flow without voltage.
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In a superconductor it can.

It's a chicken and egg problem; does current flow because of a voltage differential, or is there a voltage differential because current is flowing? The answer is "yes". :D
 
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ggunn said:
In a superconductor it can.

It's a chicken and egg problem; does current flow because of a voltage differential, or is there a voltage differential because current is flowing? The answer is "yes". :D
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In a superconducting loop anyway. A normal superconducting coil has near zero resistance but still has reactance and thus a voltage across the terminals.
 
kwired said:
Had multiple posts marked for reply - kind of gave up though, some of what I was going to say already been addressed.

But this:



Is not cold, (to me anymore) would have loved to see that temp last night. High temp yesterday never went above zero to my knowledge. Overnight forecast was for -18 low, haven't yet heard what it actually reached.
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I would get frostbite. I'm not used to dealing with temperatures like that unless I get something out of the freezer at -10.
 
mivey said:
No. That would actually be more than 60. To get 60 you need equal ohms.
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I'm confused. Equal ohms would mean 0 volts.


BTW -was wrong-spoke to spoon without thinking- you would need 1/4 the ohms on one load on a 120/240 system with am open neutral :slaphead:
 
romex jockey said:
Gentlemen,

I'd be most appreciative if i may use this opportunity to interject a particular query posed of me

Quite some time ago, conversing with a UK spark , i was asked

"Why do you lot have neutrals at all"??

I'm still at a loss......

~RJ~
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What specifically did he have in mind, if known? All 3 systems used in the UK have a neutral:



ukold1a.gif


ukold2a.gif


ukold3a.gif
 
mbrooke said:
I'm confused. Equal ohms would mean 0 volts.
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Equal ohms on a 120/208 with a floating common terminal means the common terminal of the loads is at the neutral point which is 1/2 way between the 208 terminals. This midpoint is 60 volts from the X0 point of the source wye.

mbrooke said:
BTW -was wrong-spoke to spoon without thinking- you would need 1/4 the ohms on one load on a 120/240 system with am open neutral :slaphead:
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The neutral point on the 120/240 is 1/2 way between the 240 volt terminals. A 1/4X load and 3/4X load would mean their floating common terminal is not at the neutral point. The neutral point is 1/3 of the way into the 3/4X load from the floating common terminal.
 
mivey said:
Equal ohms on a 120/208 with a floating common terminal means the common terminal of the loads is at the neutral point which is 1/2 way between the 208 terminals. This midpoint is 60 volts from the X0 point of the source wye.

The neutral point on the 120/240 is 1/2 way between the 240 volt terminals. A 1/4X load and 3/4X load would mean their floating common terminal is not at the neutral point. The neutral point is 1/3 of the way into the 3/4X load from the floating common terminal.
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I was thinking an open neutral with unbalanced loads. But yes- you are indeed correct.
 
mivey said:
I would get frostbite. I'm not used to dealing with temperatures like that unless I get something out of the freezer at -10.
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Try getting something out of a freezer when you have several hundred feet to go to get out of the freezer.

Did have a service call today about 10:00 AM was about -13F according to display in the truck. Came home about 2 hours later still was -4. Only good thing is there was't really any wind.
 
kwired said:
Try getting something out of a freezer when you have several hundred feet to go to get out of the freezer.

Did have a service call today about 10:00 AM was about -13F according to display in the truck. Came home about 2 hours later still was -4. Only good thing is there was't really any wind.
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I can't image. Was out in twenty-degree weather last week and it was too much. I probably need better gear but rarely have to deal with those temps.
 
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