Renewable Energy Questions/Discussion > Automation, Controls, Inverters, MPPT, etc
Just bought a powerjack 15000, modding.
Pete:
Hello Welshman, a few points.
Looking at your photos it appears that the inverter Earth goes to the case of the inverter from the earth connections. To get RCD circuit breakers to work you will have to connect the Neutral to the Earth. I can't see any point in connecting the input of the inverter to an RCD as they are designed to protect people from electric shock not machines. Putting an RCD on the output is really all you need to do. Usually the Neutral and Earth are connected together at the switchboard ( in Australia) . Depending on what sort of switchboard you are using there may already be an RCD there to protect the power and lighting circuits of you house.
You say that you have plugged the AC ( high voltage) inputs into the inverter and nothing happens, I would think that the inverter will need to be connected to the batteries first before it will power up.
The AC input is there to power the inverter as a battery charger or alternately to act as a change over to switch from the mains or generator through to the house supply.
welshman:
--- Quote from: Pete on November 12, 2016, 07:30:42 pm ---Hello Welshman, a few points.
Looking at your photos it appears that the inverter Earth goes to the case of the inverter from the earth connections. To get RCD circuit breakers to work you will have to connect the Neutral to the Earth. I can't see any point in connecting the input of the inverter to an RCD as they are designed to protect people from electric shock not machines. Putting an RCD on the output is really all you need to do. Usually the Neutral and Earth are connected together at the switchboard ( in Australia) . Depending on what sort of switchboard you are using there may already be an RCD there to protect the power and lighting circuits of you house.
You say that you have plugged the AC ( high voltage) inputs into the inverter and nothing happens, I would think that the inverter will need to be connected to the batteries first before it will power up.
The AC input is there to power the inverter as a battery charger or alternately to act as a change over to switch from the mains or generator through to the house supply.
--- End quote ---
thanks for the input pete. i have decided to leave the earth and neutral seperate and fit an RCBO to the output. They compare the difference between positive and neutral and they detect leak to earth, so i reckon these would provide better detection/protection.
Pete:
Hi again Welshman, I would try the RCBO out by using an RCD tester or just use a test lamp connected from the Active to the Earth connection.
If you put a 240 volt lamp between the Active and Earth and the RCBO does not trip then you will have to connect the Neutral to the Earth.
What an RCD or an RCBO does is to measure leakage current, It measures the current in the Active line and the Neutral line. They must be equal as the Neutral is the return circuit. If there is any difference it means that current is going to earth somewhere, hopefully not through you. And the breaker trips.
Here our Neutrals are always earthed, that way there is only one live conductor to worry about and if one house in the street has an earth fault it does not cause a voltage rise on all the houses after it.
Kind of complicated but we call it a MEN, (multiple Earthed Neutral system).
So try it out first,
From my tests I have always had to connect the Neutral to the Earth to get them to work.
Cheerio
Pete
welshman:
--- Quote from: Pete on November 15, 2016, 01:36:37 am ---Hi again Welshman, I would try the RCBO out by using an RCD tester or just use a test lamp connected from the Active to the Earth connection.
If you put a 240 volt lamp between the Active and Earth and the RCBO does not trip then you will have to connect the Neutral to the Earth.
What an RCD or an RCBO does is to measure leakage current, It measures the current in the Active line and the Neutral line. They must be equal as the Neutral is the return circuit. If there is any difference it means that current is going to earth somewhere, hopefully not through you. And the breaker trips.
Here our Neutrals are always earthed, that way there is only one live conductor to worry about and if one house in the street has an earth fault it does not cause a voltage rise on all the houses after it.
Kind of complicated but we call it a MEN, (multiple Earthed Neutral system).
So try it out first,
From my tests I have always had to connect the Neutral to the Earth to get them to work.
Cheerio
Pete
--- End quote ---
thanks again pete, i did a bit more "educating" on the matter, taking consensus from various places . from what i understand if we bond the earth to the netural, then if there is a short between positive ac and ground then the battery terminals will become energised with the output ac voltage and an RCD type device in this situation MUST always be fitted if you dont want to die by touching your battery terminals(or whatever else the ac is doing to the batteries).
so if we bond one of ac outputs (the one the inverter treats as neutral) to earth and inturn make that into a neutral, the inverter no longer has two live/hot/positive wires as it has as standard and such halving the chances of touching a live wire. but in doing so we must fit an rcd to shutdown the inverter output because if the live wire gets shorted to earth it will delivery the ac current back down to the battery terminals.
one thing i am not certain about is, since im going to make on of the wires a neutral by bonding it to earth on the inverter output, should i also bond earth to neutral in the generator too if it is not aready done? im assuming it must be as there are rcd's in the generator itself. the generator is a new hyundai dhy22ksem.
everything will have a common earth rod as to not induce differentials between earth points.
frackers:
Note that the bonding of Neutral to Earth must be on the inverter transformer side of the RCB. That way any leakage bypasses the RCB which causes the unbalance and hence trips it out.
Not sure where this idea of mains on battery terminals comes from. There is no mains connection to the battery, there is a great lump of transformer in the way that isolates the mains from the DC side. That's the whole point of having a transformer!! Shorting live mains to earth in fact will connect it to neutral due to the bonding which just shorts out the output of the transformer - no effect (apart from the current draw) on the DC side.
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