Two phases to house - loss of neutral
in [Repair]
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From: PeterD on 26 Nov 2009 20:56 On Thu, 26 Nov 2009 16:46:51 -0500, Van Chocstraw <boobooililililil(a)roadrunner.com> wrote: >Sylvia Else wrote: >> I have to phases of power supply to my house - so three power lines, two >> phases plus neutral. >> >> I've on occasion wondered what would happen if we lost the neutral line. >> It seems to me that we'd then have the voltage between the two phases >> across two sets of appliances, one set attached to one phase, and the >> other set attached to the other phase, with the two sets in series as a >> result of their common connection to the neutral wire. Since the two >> sets are unlikely to represent equal loads, the net result would be a >> large overvoltage on one set of appliances. >> >> My electrician says it's not an issue, but I can't see why. >> >> Any thoughts? >> >> Sylvia. > >With the exception of some pump motors, nothing in the house runs on >220. Even the stove splits 110 to the burners and 110 to the oven. No >neutral and no 110's to anything. WHere are you located that this is true? Surely not in the US/North America.
From: Sylvia Else on 26 Nov 2009 21:21 PeterD wrote: > On Fri, 27 Nov 2009 10:33:40 +1100, Sylvia Else > <sylvia(a)not.at.this.address> wrote: > >> terryc wrote: >>> On Thu, 26 Nov 2009 22:12:24 +1100, Phil Allison wrote: >>> >>> >>>>>> Would the two utility meters correctly reflect the energy I consumed? >>>>> **Briefly, yes. >>>> ** Indefinitely, actually. >>> Yep, that is how 415VAC is obtained. >> But is it how it's metered? >> >> I haven't gone through the math, and I'd overlooked the fact that each >> meter sees a power factor of less than one, so I can't say now whether I >> think the meters would read correctly. But if there's a way of looking >> at the problem that makes the answer obvious, I've yet to see it. >> >> Sylvia. > > > Do it the old fashioned way: make a test! Can't be that difficult, can > it? Of course not. I'll just get out the 415VAC resistive load I happen to have lying around, and see what registers. Sylvia.
From: kreed on 27 Nov 2009 02:24 On Nov 27, 7:46 am, Van Chocstraw <boobooililili...(a)roadrunner.com> wrote: > Sylvia Else wrote: > > I have to phases of power supply to my house - so three power lines, two > > phases plus neutral. > > > I've on occasion wondered what would happen if we lost the neutral line. > > It seems to me that we'd then have the voltage between the two phases > > across two sets of appliances, one set attached to one phase, and the > > other set attached to the other phase, with the two sets in series as a > > result of their common connection to the neutral wire. Since the two > > sets are unlikely to represent equal loads, the net result would be a > > large overvoltage on one set of appliances. > > > My electrician says it's not an issue, but I can't see why. > > > Any thoughts? > > > Sylvia. > > With the exception of some pump motors, nothing in the house runs on > 220. Even the stove splits 110 to the burners and 110 to the oven. No > neutral and no 110's to anything. Different system, there is no 110 here, only 240v and 415v As for Sylvia, yes you would be charged for the consumption. this situation would work similarly to a 3 phase delta type load The load, even unbalanced as it is, would be a certain VA at 415v - across the 2 phases How the meter responds to power factor of the load in question would be the only thing that may or may not register less KWH than actually used, but this should be to the same degree as the same load in a single phase install. IF this wasn't the case, we would have big problems regarding billing on installs having both single and 3 phase loads on the same meters in 3 phase premises.
From: F Murtz on 27 Nov 2009 03:53 Sylvia Else wrote: > PeterD wrote: >> On Fri, 27 Nov 2009 10:33:40 +1100, Sylvia Else >> <sylvia(a)not.at.this.address> wrote: >> >>> terryc wrote: >>>> On Thu, 26 Nov 2009 22:12:24 +1100, Phil Allison wrote: >>>> >>>> >>>>>>> Would the two utility meters correctly reflect the energy I >>>>>>> consumed? >>>>>> **Briefly, yes. >>>>> ** Indefinitely, actually. >>>> Yep, that is how 415VAC is obtained. >>> But is it how it's metered? >>> >>> I haven't gone through the math, and I'd overlooked the fact that >>> each meter sees a power factor of less than one, so I can't say now >>> whether I think the meters would read correctly. But if there's a way >>> of looking at the problem that makes the answer obvious, I've yet to >>> see it. >>> >>> Sylvia. >> >> >> Do it the old fashioned way: make a test! Can't be that difficult, can >> it? > > Of course not. I'll just get out the 415VAC resistive load I happen to > have lying around, and see what registers. > > Sylvia. Two large lamps in series.
From: Sylvia Else on 27 Nov 2009 06:31
F Murtz wrote: > Sylvia Else wrote: >> PeterD wrote: >>> On Fri, 27 Nov 2009 10:33:40 +1100, Sylvia Else >>> <sylvia(a)not.at.this.address> wrote: >>> >>>> terryc wrote: >>>>> On Thu, 26 Nov 2009 22:12:24 +1100, Phil Allison wrote: >>>>> >>>>> >>>>>>>> Would the two utility meters correctly reflect the energy I >>>>>>>> consumed? >>>>>>> **Briefly, yes. >>>>>> ** Indefinitely, actually. >>>>> Yep, that is how 415VAC is obtained. >>>> But is it how it's metered? >>>> >>>> I haven't gone through the math, and I'd overlooked the fact that >>>> each meter sees a power factor of less than one, so I can't say now >>>> whether I think the meters would read correctly. But if there's a way >>>> of looking at the problem that makes the answer obvious, I've yet to >>>> see it. >>>> >>>> Sylvia. >>> >>> >>> Do it the old fashioned way: make a test! Can't be that difficult, can >>> it? >> >> Of course not. I'll just get out the 415VAC resistive load I happen to >> have lying around, and see what registers. >> >> Sylvia. > Two large lamps in series. > I don't have any. I'd have to buy them. Anyway, all a test would do is show that the answer is probably correct. It wouldn't make it any more obvious. Sylvia. |