Voltage Between Earth and Neutral

[MOD85]

Hello everyone

i have a step-up transformer which i?m connecting one terminal to L and the other one to N, the voltage between this to is 110VAC. So im connecting X1,X3 and X2,X4

So in the other side of the transformer a have 220VAC between the L and the N. Im connecting H1,H3 and H2,H4.

See the attached picture for the wiring diagram of the transformer

My first question is, why do a read a voltage between the N(H2,H4) and Earth for about 90VAC??? (The voltage between earth and L is 170VAC)

the second one is, when i connect a load between L(H1,H3) and N(H2,H4) the voltage between N and Earth is 110VAC and the voltage between L and Earth is 110VAC.

The reason i?m doing this is because a neeed 220VAC Monophase.

Hope anyone can clear this to me.

Thanks in advance

 

[raider1]

Have you grounded the secondary of this transformer?

An ungrounded secondary will have a fluctuating voltage to ground.

Chris

 

[MOD85]

The Neutral line you mean?

If that its the question the answer its no. I was told that if a ground the neutral line on the secondary side, the system will not be overcurrent protected.

 

[raider1]

I was told that if a ground the neutral line on the secondary side, the system will not be overcurrent protected.

How are you providing overcurrent protection of the secondary?

Typically grounding of the secondary will not affect the overcurrent protection of the secondary.

Chris

 

[MOD85]

so you think that i need to ground the neutral of the secondary side, that will make the read between the earth and my neutral be goes as low as 0VAC

a co-worker also said that i get that reading because there is a imaginary resistence between the neutral and the ground. so maybe the voltage i read doesn?t have any current, because its a floating voltage...

those that ring a bell???

 

[raider1]

so you think that i need to ground the neutral of the secondary side, that will make the read between the earth and my neutral be goes as low as 0VAC

Without grounding the secondary of the transformer you will have a voltage between ground and either conductor of the secondary of the transformer.

By the way, you don't have a neutral on the secondary of this transformer.

If you ground a conductor then you will have a grounded conductor but with a single volatge secondary you will never have a neutral.

a co-worker also said that i get that reading because there is a imaginary resistence between the neutral and the ground.

This makes no sense what so ever. there is no such thing as an imaginary resistance.

so maybe the voltage i read doesn?t have any current, because its a floating voltage...

those that ring a bell???

No, the reason that you are reading a volatge is that the secondary is ungrounded and you will read a fluctulating voltage between either conductor of the secondary and ground.

I would recomend that you review sections 250.20(B) for what systems are required to be grounded and 250.21(B) for ungrounded system ground detectors.

Also you did not specify how you were protecting the secondary of the transformer and the secondary conductors from overcurrent.

Chris