I have an inverter that is single phase at 240/120 volts on the AC side of the inverter. I am wanting to use the inverter for training purposes. The only house power that I have available is 208/120 volts. Will it be permissible to use single phase 208 volts to supply the inverter for the house power. Again, this will be for training purposes only. The tech support from the inverter company said that it would be ok. I was just wondering if anyone had any suggestions. I am sure that I can use a transformer but if I don't need to use it then I would have that much less weight on my trainer. At the same time, I don't want to have a smoke test with it either. Thanks
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PV Inverter Input Voltage from House/Utility Power
- Thread starter ftrost
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winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
Ya got to look at the output specifications for the inverter in question.
Does the data sheet specifically permit 208V, or is 208V in the allowed utility voltage range?
Does your particular inverter require a neutral and will it be happy with 'psingle' phase power (two legs of a 3 phase 208/120V supply)?
For your training will you be making current measurements, and do you want those measurements to look the same as what you expect in a residential situation? (For example, clamping multiple conductors to look for net current will give different results on a 120/240V single phase system vs 208/120V three phase systems.)
If the manufacturer says it is 'ok' then it probably is, but the spec sheet will tell you the caveats of 'ok'. Feel free to post a link to the actual model you will be using.
-Jon
Does the data sheet specifically permit 208V, or is 208V in the allowed utility voltage range?
Does your particular inverter require a neutral and will it be happy with 'psingle' phase power (two legs of a 3 phase 208/120V supply)?
For your training will you be making current measurements, and do you want those measurements to look the same as what you expect in a residential situation? (For example, clamping multiple conductors to look for net current will give different results on a 120/240V single phase system vs 208/120V three phase systems.)
If the manufacturer says it is 'ok' then it probably is, but the spec sheet will tell you the caveats of 'ok'. Feel free to post a link to the actual model you will be using.
-Jon
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
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- Consulting Electrical Engineer - Photovoltaic Systems
An inverter connected to the grid has to be able to supply the same voltage and phase relationship that the grid supplies to it. Look at the inverter spec sheet for output voltage.I have an inverter that is single phase at 240/120 volts on the AC side of the inverter. I am wanting to use the inverter for training purposes. The only house power that I have available is 208/120 volts. Will it be permissible to use single phase 208 volts to supply the inverter for the house power. Again, this will be for training purposes only. The tech support from the inverter company said that it would be ok. I was just wondering if anyone had any suggestions. I am sure that I can use a transformer but if I don't need to use it then I would have that much less weight on my trainer. At the same time, I don't want to have a smoke test with it either. Thanks
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
The reverse polarity protection is for the DC side; is that minimum voltage on the input (DC) or the output (AC)? If it is on the output, then you cannot connect it to 208V.It is a Solar Edge M/N SE7600H-US. The minimum voltage is 211 VAC and has reverse polarity protection. Thanks
EDIT: Here is the data sheet for that inverter; it is not 208V compatible.
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
Here is the datasheet for that inverter series:
Note on page 2 the voltage ratings. You cannot use the SE7600H-US on a 208V system and be in spec.
Interestingly, several models from the same manufacturer _are_ rated for 208V. If you change to a SE6000H-US then you will be perfectly fine using your 208V supply.
The datasheet does not specify _why_ some units are dual rated for 240V or 208V whereas others are only rated for 240V. The issue might be that all will work fine on 208V but only some are tested, or it might be that some critical component needed for dealing with the phasing of 208V is only installed in some of the units.
-Jon
Note on page 2 the voltage ratings. You cannot use the SE7600H-US on a 208V system and be in spec.
Interestingly, several models from the same manufacturer _are_ rated for 208V. If you change to a SE6000H-US then you will be perfectly fine using your 208V supply.
The datasheet does not specify _why_ some units are dual rated for 240V or 208V whereas others are only rated for 240V. The issue might be that all will work fine on 208V but only some are tested, or it might be that some critical component needed for dealing with the phasing of 208V is only installed in some of the units.
-Jon
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
A transformer might not work for you since the phase voltages in 208/120V power are 120 degrees apart relative to the neutral. You could get the 208V to 240V phase to phase but the voltage to neutral would be wrong. I would get a different inverter, one that can run at 208/120V natively.Thanks-It didn't feel right when the factory rep told me that it would be ok. I will plan on getting a transformer. Thanks again
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
A transformer might not work for you since the phase voltages in 208/120V power are 120 degrees apart relative to the neutral. I would get a different inverter, one that can run at 208/120V natively.
A buck-boost (non-isolating autotransformer) could have this problem.
A true isolating 208:120/240V single phase transformer would re-generate all the phasing, but would be heavier for any given power level.
I concur: use an inverter designed for 208/120V.
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
I guess he could get a 208V to 240V transformer with no neutral on the primary and a grounded center tapped secondary, but he would probably spend as much on the transformer as he would on a different inverter.
This is why it's not a good idea to blindly accept everything a support person tells you on the phone or in an email. Some of them are surprisingly unknowledgeable about their own products and even less knowledgeable on how to use them in the field where they have to comply with codes.Thanks-It didn't feel right when the factory rep told me that it would be ok. I will plan on getting a transformer. Thanks again
AlbertL57
Member
- Location
- Falls Church, VA
- Occupation
- Solar maintainer
Certain blocks in Washington DC have 120/208V split-phase residential services (two phases and a neutral off a wye-connected three-phase transformer bank). The Solaredge inverters with 208V capability will work on that supply, but the "secret" is setting the Country to "US 208V NO NEUTRAL". Apparently that forces the inverter to look at only the line-to-line voltage, so it's not confused by the 120-degree phase angle relative to the neutral.
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
Right.
As Jon pointed out, what's odd is that Solaredge only shows this feature available on certain models of the H series inverters. (IIRC, that wasn't true of the older 'A' series, they all supported it.)
As Jon pointed out, what's odd is that Solaredge only shows this feature available on certain models of the H series inverters. (IIRC, that wasn't true of the older 'A' series, they all supported it.)
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
I believe that UL requires the inverter to monitor phase to neutral voltage, so some of the models may be grandfathered in from before that change?Certain blocks in Washington DC have 120/208V split-phase residential services (two phases and a neutral off a wye-connected three-phase transformer bank). The Solaredge inverters with 208V capability will work on that supply, but the "secret" is setting the Country to "US 208V NO NEUTRAL". Apparently that forces the inverter to look at only the line-to-line voltage, so it's not confused by the 120-degree phase angle relative to the neutral.
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