H
hughesy
hi when you measure between phase and phase you get 415 volts and between pase and neutral you get 240 why is it 240 and not say half of 415 .
Discuss 3 phase voltages in the Canada area at ElectriciansForums.net
cheers i was hoping they woul be, not after a major discussion although its very welcome just need a basic anser i know the phases are lagged at 120 deggrees and that each phase is at a differant level than each other phase and a few other basic things just not this one.You are opening a WHOLE can of worms now
Lenny or someone else may be along later to explain all in great detail.
very good answer but not quite what i was looking for although very helpfull and a good learning point .thanks mateHi,
Let's see if I can get this right -
The voltage between two phases is 400 v - this is the potential difference
between the two lines at any moment in time
eg. If L1 = 180 v then L2 will be (minus) - 220 v giving
a PD of 400 v
This is because they are 120 degrees out of phase with each other.
To see it properly you would have to draw the two sine waves.
The formula that gives this result (for a star connection) is:
line voltage = sq rt of 3 x phase voltage
so
line voltage = 1.732 x 230 = 400 v (approx)
I think that's right
Cheers
Wayne
Its very difficult to explain in words so I have
attatched a sketch of how 240v line voltage's relation to 415v phase voltage is derived from.
Not very good at sketching
I hope this helps
Ray
Good answer Wayne.
Hughesy mate, what are you looking for then??
Hi,
Let's see if I can get this right -
The voltage between two phases is 400 v - this is the potential difference
between the two lines at any moment in time
eg. If L1 = 180 v then L2 will be (minus) - 220 v giving
a PD of 400 v
This is because they are 120 degrees out of phase with each other.
To see it properly you would have to draw the two sine waves.
The formula that gives this result (for a star connection) is:
line voltage = sq rt of 3 x phase voltage
so
line voltage = 1.732 x 230 = 400 v (approx)
I think that's right
Cheers
Wayne
Interesting question. I know it's to do with the fact AC is delivered as a sine wave and so the voltage specified is sort of an average, and that the voltage is expressed in terms of RMS to show this, but that's as far as I can go and that may not be properly correct, so I'm also looking forward to the more detailed explanation. I'd like to know what the actual voltage level is when considering peak to peak. You have to consider that during one cycle of AC voltage, the voltage is climbing from relative 0V to whatever the peak voltage is, and then back to 0V before starting a negative cycle from 0V to the peak. Ug, you've made me try to use my brain, and now look what's happened. Danger Will Robinson.
Nothing to do with Mary queen of scots suffering sea-sickness---apparantly.So that's 3P and relative PD in aphase conductors explained, now why is orange jam called marmalade?
Good answers wayne and raylewis ! so how does split phase work ? 460-480v lol only joking ! southern electric use this alot in remote areas like farms etc saves expence sending 3 phases across fields etc !
Split Phase, 460/480v Single hot wire and N dumped into a tranny and same voltage out with a center tap = 230/240, N, 230/240
I wouldn't disagree with you on that, it works both ways. In the U.S.also it's 2 hots and a nail in the ground for N/E. On this side of the pond both systems have been used.(I've met them) I'm not sure what the current GB standard is or if it's different for different suppliers.I was under the impression that it was 2 "hots" in and locally sourced neutral(earth)for your centre tap out.giving 230 out or 460 if reqd(eg welder) But I bow to your supierior knowledge.
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