neutral-earth voltage on 3-phase sytem

[ColJack]

ah.. in at the deep end then..
it's the old "test the new guy" fault chaps.. no need to worry..
there'll be a transformer on the real L2 phase and neutral.. with the output tied to the neutral to the machine..

BTW, in case you have no sense of humour, that was supposed to be a joke.. if it turns out to be true, you owe me at least 2 pints..

 

[eds_taff]

Yep, right in at the deep end, I don't mind though, as long as I can get it sorted!!

And if that turns out to be what the problem is mate, and you think its worth coming all the way down to sunny South Wales, I will happily buy you a couple of pints of our finest SA

 

[ColJack]

always worth a trip to cardif.. lovely beaches there...

 

[Click-Sure]

They tested an atomic bomb there a couple of years ago didn't they? I heard it caused £7 worth of damage!

 

[ColJack]

you been watching too much Doctor Who or Torchwood.. they don't really blow up stuff there you know..

 

[bernardgreen]

They tested an atomic bomb there a couple of years ago didn't they? I heard it caused £7 worth of damage!

Yes, A bit of debris landed in Swansea and broke a .....

 

[bhm1712]

what meter are you using to measure these values? is it calibrated?

the 360 volts phase to neutral seem overly high, almost too high to believe. that would make the phase to phase values way higher than 415 in which case i doubt the supply is 415 volts.

 

[ericmark]

Sounds like reading I got when working on an IT system. So I would guess neutral not connected?

I have seen where a star wound motor was used to generate a neutral and changing the motor for a delta wound has resulted in no neutral.

 

[bhm1712]

the 360 volts doesnt sound right to me, if thats from phase to neutral then between phases would be close to 625 volts ( 360 x 1.732 = 623 volts)

 

[ColJack]

not if the neutral is floating..

 

[eds_taff]

They tested an atomic bomb there a couple of years ago didn't they? I heard it caused £7 worth of damage!

Yep, but if it was in Bridgend it would have been £8 worth of damage

 

[eds_taff]

what meter are you using to measure these values? is it calibrated?

Calibrated Fluke meter

 

[eds_taff]

Sorry I havn't posted back, didn't have chance to test anything yet as I have been up in Stoke working for a few days.

Hopefully get a chance to have a look tomorrow, if I don't get sent off to the back of beyond again!

 

[plugwash]

the 360 volts doesnt sound right to me, if thats from phase to neutral then between phases would be close to 625 volts ( 360 x 1.732 = 623 volts)

Correction: if that was from ALL phases to neutra iit would be, that is clearly not the case here

Since the phase-phase and phase-earth measurements are normal and the phase-neutral are all screwy (two high, one low) the only sane explanation is that the neutral is f*cked.

 

[eds_taff]

Just to let you know guys, you were spot on.

Checked out the dis board today, and found the neutral connection at the main switch was VERY loose !!

It probably hasnt been noticed much before as the machine is not used very often, and everything else that is fed from the board does not use a neutral.

Thanks people