Rewiring generator to match country requirements

[scubadon]

Good day all,

I'm writing from the Commonwealth of Dominica (NOT Dominican Republic) where we have single phase 230V, 50Hz.

I'm managing a property where the owner purchased a generator from the US and asked for it to be wired accordingly along with a Auto Transfer Switch. I've attached some pictures of name plates, invoice etc.

It seems to me the generator itself isn't wired appropriately for the 230V/50Hz we use here.

first problem that's evident is, when generator is feeding power to the house I get approx. 115V from Ground to L and 115V from Ground to N. at outlets. As you can see in the transfer switch photo they have brown 115V on one side and blue 115V on the other side, this is coming from the generator obviously, and obviously wrong..

Second problem is, if I try to put generator in AUTO it always immediately tries to start as the transfer switch sees wrong current from the grid.

What I'm looking for is some insight of what is wrong with the system as it is (I believe the genie needs to have the internal connections modified from double delta) and how to steer the local electricians in the right direction.

Thanks in advance for any help

Don

 

[Lucien Nunes]

First, re. getting the ATS to correctly detect the incoming grid power, there are a couple of programmable functions on that controller. It might need nothing more than the threshold voltage turned down a bit. According to the bumf here: https://mtspowerproducts.com/admin/data_sheet/TCS3P125.pdf it's parameter 8, normally set to 180V but who knows what yours is set to. Worth a check.

I don't see anything that would allow it to be configured for sensing 0-240V as distinct from 120-0-120V, so if the controller is specifically looking for a US-style 120-0-120 split phase supply, it might simply not be compatible. I think that would need a discussion with the manufacturers' technical people to clarify.

Once the generator is running, it would be reasonable to expect 120-0-120V on the output because as labelled on the panel, the neutral is floating rather than connected to ground. I.e. it is supplied in 'IT' configuration and if you want it 'TN' i.e. with a grounded neutral, you make the neutral-ground link (USA term: 'bond') yourself. That would be either the middle wire to ground to make 120-0-120 or one end (e.g. the blue) to make 0-240.

The fact that it is sitting with 120V either side of ground at the moment doesn't mean the middle wire is solidly grounded - outputs often float to a symmetrical position by themselves. But you must check, before linking to one end, to make 0-240. I cannot see the middle wire in the panel anywhere, it's probably insulated with the generator itself but a thorough check is essential.

 

[Marvo]

Just to add it's not safe to connect the generator in 110-0-110 configuration to an electrical installation that has single pole circuit breakers. I don't know your local regs but where I am it's not legal to connect any form of suplimentary electrical supply to a domestic premises where the neutral and earth aren't linked at source.

 

[scubadon]

First, re. getting the ATS to correctly detect the incoming grid power, there are a couple of programmable functions on that controller. It might need nothing more than the threshold voltage turned down a bit. According to the bumf here: https://mtspowerproducts.com/admin/data_sheet/TCS3P125.pdf it's parameter 8, normally set to 180V but who knows what yours is set to. Worth a check.

I don't see anything that would allow it to be configured for sensing 0-240V as distinct from 120-0-120V, so if the controller is specifically looking for a US-style 120-0-120 split phase supply, it might simply not be compatible. I think that would need a discussion with the manufacturers' technical people to clarify.

Once the generator is running, it would be reasonable to expect 120-0-120V on the output because as labelled on the panel, the neutral is floating rather than connected to ground. I.e. it is supplied in 'IT' configuration and if you want it 'TN' i.e. with a grounded neutral, you make the neutral-ground link (USA term: 'bond') yourself. That would be either the middle wire to ground to make 120-0-120 or one end (e.g. the blue) to make 0-240.

The fact that it is sitting with 120V either side of ground at the moment doesn't mean the middle wire is solidly grounded - outputs often float to a symmetrical position by themselves. But you must check, before linking to one end, to make 0-240. I cannot see the middle wire in the panel anywhere, it's probably insulated with the generator itself but a thorough check is essential.

Thanks for the input, Lucien.

I did check the settings on the ATS controller. I think the primary issue was it was set to 3 phase on line 1.

Now the ATS displays and monitors the grid properly.

As for the weird voltage readings I mentioned at outlets when Genie was supplying the house. That now reads as I would expect (not being an electrician) ground to Line 230ish V, ground to neutral less than 1V. Why this changed I have no idea except that there are some renovations going on and they ran new conduit and wires from the meter to house as the old one was water flooded.

As for the AUTO mode on Genie. It still starts up as soon as AUTO is selected and STATUS shows MAINS FAILURE. However, it no longer activates the ATS to switch over as the ATS is reading the grid properly. When I do turn off main breaker to house the ATS sees this failure and the unit switches to generator. I can go back and forth from main to generator by switching OFF/ON the house main breaker.

So the last problem is making the generator sense mains voltage properly.

Any thoughts. I guess I'll start by checking continuity of remote start wires from ATS to generator. There are only 4 wires running to genie in this regard.

-Ground wire for remote start
-remote start wire
-L120 for trickle charger
-G120 for trickle charger

Cheers