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V-0-V Generator?

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23 hours ago, P1000 said:

He has already taken those measurements and others. It is not V0V. It is an inverter generator.

I can't tell that he has taken these measurements from the information in this thread.

I see that he has taken voltage measurements referenced to Earth, but what does he consider to be earth?

That is why I was very specific in differentiating the generator chassis earth from the system Earth.

If the measurements are from the system earth only, a V-0-V has not been ruled out and the generator chassis could be live.

 

 

 

 

 

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15 minutes ago, phil.g00 said:

I can't tell that he has taken these measurements from the information in this thread.

I see that he has taken voltage measurements referenced to Earth, but what does he consider to be earth?

That is why I was very specific in differentiating the generator chassis earth from the system Earth.

If the measurements are from the system earth only, a V-0-V has not been ruled out and the generator chassis could be live.

I see the problem. Chassis is connected to earth as mentioned in this post:

On 2020/02/05 at 11:19 AM, DrewZA said:

Hey All

I have a Ryobi RG-2000i inverter generator that I wired into the db, it was working well to keep the lights on, internet up and the beers cold but then I noticed that my LED motion sensor light was dimly lit even when it wasn't activated so I did some tests and found live between neutral and earth. I immediately shut everything down, sat in the dark mumbling to myself about the state of the country 😂 A quick google search later and I found this whole story of V-0-V generators and safely wiring them to a db.

I would like to modify the generator so that it is no longer V-0-V but at this stage being an inverter type, I don't know if it's even possible. Everything is compact, with only a small access panel so I don't see any exposed alternator contacts like the picture floating around shows. If needs be I'll strip the whole thing down to pieces but I'm not looking forward to that.

There is however an exposed an earth busbar on the side of the motor. My thinking is that one of them may be the centre tap? Disconnect it, insulate the ring terminal, wire a neutral from the inverter output to the earth busbar and done, or is that a bit too optimistic?

I just need to find the centre tap. From left to right 1, 2, 3, 4.

1. Unknown earth, heat shielded, disappears under the motor - possible candidate for centre tap?

2. Wired to the ignition coil. You can stay.

3. Unknown earth, disappears into a plastic box - possible candidate for centre tap?

4. Yellow/Green, wired the the inverter chassis, gnd terminal, plug gnd, and plug plate. You can stay.

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Am I on the right track here?

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OK, it appears that you have been involved in a capacity outside of this thread.

 I'll take it then, it has been clearly established that the chassis earth, the system earth and the system neutral are all directly bonded at the same potential.

Now, it must be established that sufficient earth fault current will flow during an L-E and N-E fault.

The inverter zero sequence source impedance will be different to the grid system.

So it needs to be confirmed that the earth leakage protection still works for these two earth fault types when powering the system from the generator.

 

 

 

Edited by phil.g00

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1 hour ago, phil.g00 said:

I can't tell that he has taken these measurements from the information in this thread.

I see that he has taken voltage measurements referenced to Earth, but what does he consider to be earth?

That is why I was very specific in differentiating the generator chassis earth from the system Earth.

If the measurements are from the system earth only, a V-0-V has not been ruled out and the generator chassis could be live.

 

 

 

 

 

In testing the generator was standalone, isolated from any installation wiring. The measurements were:

L-N = 230V
L-Chassis E = 230V
N-Chassis E = 0V

 

 

 

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4 minutes ago, DrewZA said:

L-N = 230V
L-Chassis E = 230V
N-Chassis E = 0V

And the chassis E is now connected to the system E, I understand.

Edited by phil.g00

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I'll check this measurement shortly. Wouldn't it be irrelevant though, this requires intentionally unbonding the connection between gen chassis earth and system earth?

3 minutes ago, phil.g00 said:

And chassis E to system E?

 

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6 minutes ago, DrewZA said:

I'll check this measurement shortly. Wouldn't it be irrelevant though, this requires intentionally unbonding the connection between gen chassis earth and system earth?

Sorry, if its directly bonded this measurement is not necessary.

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On 2020/02/07 at 10:56 AM, phil.g00 said:

OK, it appears that you have been involved in a capacity outside of this thread.

 I'll take it then, it has been clearly established that the chassis earth, the system earth and the system neutral are all directly bonded at the same potential.

Now, it must be established that sufficient earth fault current will flow during an L-E and N-E fault.

The inverter zero sequence source impedance will be different to the grid system.

So it needs to be confirmed that the earth leakage protection still works for these two earth fault types when powering the system from the generator.

 

 

 

I checked out the EL with a plug tester over the weekend and it's tripping at 25mA. I'm really happy with the outcome, thanks for the help all!

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