Split Phase vs Single Phase confusion

BB. · June 2019

When I was designing large computer systems in another life--I looked around and found that there were few actual "hard limits" for "acceptable" utility voltage... And acceptable nominal line voltage has changed over time (generally increasing).

For example, when I was a kid, 110 VAC (220 VAC) was the nominal voltage... Slowly increased to 117 VAC (234) and now in the 120-125 nominal range. (Europe seemed to move from 220 to 230 VAC 50 Hz).

Now, I would call 105-127 VAC (210 to 254 VAC) to be, sort of, US/North American standard for single phase. And ~132/264 VAC to be the actual acceptable maximum (when you call the power company and complain, most GT inverters shutdown around 260-264 VAC). Years past, typically only saw ~264 VAC at more remote sites in Australia (end of utility distribution has "iffy" regulation almost anywhere).

Some places in Japan are ~100 VAC nominal...

Throw in that (for example) the USA has two major 3 phase standards... Delta and Wye connected transformers--Which give 120/208 VAC nominal (Wye) and 120/240 VAC (Delta)...

You see that many "appliances" (motors, ec.) are designed for world wide sales, so you may see name plate ratings that have different "acceptable" input voltage ranges.

When the major loads were filament lighting and refrigerators (induction motor compressors)--Voltage was a big issue between damaged refrigerator motors (below 100 VAC brownouts) to 105-132 VAC input for lights (dim/yellow light at 105 volts, bright white and short life at 132 VAC).

For us, our utilty (probably most utilities?) have learned to cut power rather than brownout (save motors from stalling/overheating). And with electronic power supplies for computers/electronics/LED lighting/ballasts for fluorescent lamps, etc.), many devices have very wide acceptable voltage ranges (i.e., dual voltage range 100-125/200-250 VAC) or wide range supplies (100-260 VAC for PFC power factor corrected power supplies/AC input) and actual specific line voltage is not as important (you can take your computer/cell phone charger to almost anywhere in the world these days).

Your Inverter system is programmable so you can decide what is acceptable for your needs... For example you may set AC1 (utilty power) to 110-126 VAC / 220-252 VAC at 60 Hz +/- 1 Hz and set AC2 to 105-130 VAC / 210-260 VAC 60 Hz +/- 10 Hz for a mechanically regulated (voltage/speed) genset (so that you can get AC power and Charging under any "useful" genset conditions.

My house typically runs ~122/244 to 124/248 VAC (near San Francisco CA) nominal (not that I have logged the voltage over time).

-Bill

DickyDck · June 2019

BB. said:

When I was designing large computer systems in another life--I looked around and found that there were few actual "hard limits" for "acceptable" utility voltage... And acceptable nominal line voltage has changed over time (generally increasing).

For example, when I was a kid, 110 VAC (220 VAC) was the nominal voltage... Slowly increased to 117 VAC (234) and now in the 120-125 nominal range. (Europe seemed to move from 220 to 230 VAC 50 Hz).

Now, I would call 105-127 VAC (210 to 254 VAC) to be, sort of, US/North American standard for single phase. And ~132/264 VAC to be the actual acceptable maximum (when you call the power company and complain, most GT inverters shutdown around 260-264 VAC). Years past, typically only saw ~264 VAC at more remote sites in Australia (end of utility distribution has "iffy" regulation almost anywhere).

Some places in Japan are ~100 VAC nominal...

Throw in that (for example) the USA has two major 3 phase standards... Delta and Wye connected transformers--Which give 120/208 VAC nominal (Wye) and 120/240 VAC (Delta)...

You see that many "appliances" (motors, ec.) are designed for world wide sales, so you may see name plate ratings that have different "acceptable" input voltage ranges.

When the major loads were filament lighting and refrigerators (induction motor compressors)--Voltage was a big issue between damaged refrigerator motors (below 100 VAC brownouts) to 105-132 VAC input for lights (dim/yellow light at 105 volts, bright white and short life at 132 VAC).

For us, our utilty (probably most utilities?) have learned to cut power rather than brownout (save motors from stalling/overheating). And with electronic power supplies for computers/electronics/LED lighting/ballasts for fluorescent lamps, etc.), many devices have very wide acceptable voltage ranges (i.e., dual voltage range 100-125/200-250 VAC) or wide range supplies (100-260 VAC for PFC power factor corrected power supplies/AC input) and actual specific line voltage is not as important (you can take your computer/cell phone charger to almost anywhere in the world these days).

Your Inverter system is programmable so you can decide what is acceptable for your needs... For example you may set AC1 (utilty power) to 110-126 VAC / 220-252 VAC at 60 Hz +/- 1 Hz and set AC2 to 105-130 VAC / 210-260 VAC 60 Hz +/- 10 Hz for a mechanically regulated (voltage/speed) genset (so that you can get AC power and Charging under any "useful" genset conditions.

My house typically runs ~122/244 to 124/248 VAC (near San Francisco CA) nominal (not that I have logged the voltage over time).

-Bill

So for laughs I tried to adjust the AC1 voltages, but it won't let me go to 230/250, seems like it only let me go 110ish/140ish. So I'm hoping it is just reading one particular leg, since the inverter does see AC in at 240, at least in the one section

BB. · June 2019

Yes, it is reading the Lx to neutral leg voltage. In theory, L1-L2 is just 2x the Lx-Neutral voltage.

My first GT inverter measured L1 to L2 for line voltage... Due to changes in UL/NRTL safety regulations (I think), the regulations (in North America) needed the inverter to also monitor Lx to neutral voltage (look for lost/broken neutral connections). The quick fix by the electrician (this was a replacement GT inverter) was to connect the chassis ground to Neutral so that it could measure Lx to neutral voltage (there was no neutral connection to the original inverter since neutral was not used).

It was a little silly, because the GT inverter only had L1 and L2 (plus ground) connections--It did not need or use Neutral for any reason... But the powers that be decided that a "faulty" neutral anywhere in the home should also be a reason for the (240 VAC only) GT inverter to shutdown.

Such is life...

-Bill

Tecnodave · June 2019

DickyDoc,

The first page is the readout of current conditions......That is what is happening at the time of the screen shot.
the line "Grid AC voltage" is the current L1-L-2 voltage.......the 240 volt values
at the bottom of that page is AC1 voltage that is the L-1 or L-2 to neutral voltage.......the 120 volt values.....this is to check for loss of neutral connection.

The second page is the limits programmed into the XW , not current values. These limits are set by the POCO....(Your local power company) They are imposed by the PUC....The Public Utility Commission....(In California).......or whatever local agency that governs public utilities in your zone of the woods. These are preset values that limit what the XW can connect to. This is to protect against your XW from powering into a grid that is not stable at the moment.

The AC 1 low limit is set to 106 volts L-1 or L-2 to neutral low limit
the AC1 high limit is set to 132 volts L-1 or L-2 to neutral high limit

This is set to limit each L-1 or L-2 to a min-max value for the same reason, to protect against loss of neutral

so if adding the two low limit values you get a low L-1 and L-2 voltages that is 206 volts minimum operating voltages
so if adding the two high limit values you get a high L-1 and L-2 voltages that is 264 volts maximum operating voltage

OK YOU GOT IT

PAGE 1 ......current values
PAGE 2 .......limits

Dave Angelini said it well........YOU ARE OVERTHINKING THIS!
Tecnodave is saying........YOU ARE OVER THINKING THIS

OK YOU GOT IT

DONT MESS WITH THESE SETTINGS.......YOU DO NOT UNDERSTAND WHAT THIS IS....LEAVE IT ALONE
IF YOU MUCK THIS UP YOUR INSTALLER WILL CHARGE YOU TO SET IT UP AGAIN

Sorry to be so blunt, stay out of there! you are not qualified to change these settings

I have never seen such a wide range of grid frequencies a low of 52 hz and a high of 67 hz, if the grid changed that much in frequency the whole grid would crash as in the NYC grid crash that blacked out the east coast several dozen years back!

TD out

Tecnodave · June 2019

And to add to that

3 phase is for large apartment houses, three phase is fed to the master panel but each apartment has single phase fed from the 3 phase main panel, only the central heating and or central water heater has 3 phase, the apartments do not get 3 phase

large commercial and industrial is 3 phase

Single residences are always single phase, no exception
there is 120 volt only SINGLE PHASE
there is also 120/240 volt SINGLE PHASE. also known as SPLIT PHASE, it is not poly phase

THREE PHASE IS NEVER IN A SINGLE HOUSEHOLD......the PUC does not allow THREE PHASE IN A HOUSEHOLD

YOU HAVE SINGLE PHASE 120/240 volt service, the most common in America, center tap grounded AKA SPLIT PHASE

LEAVE IT ALONE

TD out.....

mcgivor · June 2019

Tecnodave said:

And to add to that

3 phase is for large apartment houses, three phase is fed to the master panel but each apartment has single phase fed from the 3 phase main panel, only the central heating and or central water heater has 3 phase, the apartments do not get 3 phase

large commercial and industrial is 3 phase

Single residences are always single phase, no exception
there is 120 volt only SINGLE PHASE
there is also 120/240 volt SINGLE PHASE. also known as SPLIT PHASE, it is not poly phase

THREE PHASE IS NEVER IN A SINGLE HOUSEHOLD......the PUC does not allow THREE PHASE IN A HOUSEHOLD

YOU HAVE SINGLE PHASE 120/240 volt service, the most common in America, center tap grounded AKA SPLIT PHASE

LEAVE IT ALONE

TD out.....

My belief is that @DickyDck is asking questions to get an understanding of how the system works, how and why the settings are what they are, self education is never a bad idea. Back in post 3 I had mentioned what I thought the values in the settings posted were, the manual doesn't clarify and I didn’t want to give erroneous information, hense the word "likely"

Not everyone has a background in electrical distribution so it's easy to understand the confusion, having said that, my belief is if someone has no formal electrical training, they have no business touching it, electricity is invisible, odorless and silent, but it bites.

Tecnodave · June 2019

DickyDoc,

In rereading the whole thread I do see the evidence of you having been in there and mucking things up, your admission of trying to reset the AC1 values confirms that.....the grid frequencies are way out of whack......there is no grid anywhere that is 52 hz to 67 hz if this ever happened one generating station would dead short circuit the next one and what you would have is a ripple effect where one power station blows out the next which blows out the next ad Infinium

This is what happened in NYC where one generating station got off frequency and blew out the next then blew out the next,continuing taking out the entire north east, I can't remember just how many power plants were blown out but the east coast was out of power over a huge area for weeks to rebuild the grid

The AC 1 input is the grid and the frequency must be tightly controlled

The AC 2 input is for the generator which can have a wide voltage range to account for the generator not being stable

On the national power grid the frequency is tightly controlled as one generator being 1 cycle off with the next one will start blowing things up within 18 milliseconds, the time of one cycle on the 60 hz grid.

Schneider does have the right to immediately void your warranty.........They do read the forums......

My advise .....get out of there....you are not qualified....hire who you may and have your system reset to factory settings

Dave Angelini is qualified but he does deserve a consultation fee and more to reset your system.

Quit messing with it....

the other dave

DickyDck · June 2019

I can reset to factory and start from scratch with no issues, both the installer and Schneider have had me do that several times. The only thing that I need to reset are the battery settings, and turn A/C coupling off... and the load shaving again.

DickyDck · June 2019

Ha! And you were correct. Had I looked farther down the initial readings page I saw that AC1 and AC2 were both hovering around 120ish, and added together with basic mathematics equals....240ish

sorry for wasting everyone’s time when I should have just scrolled down a bit farther, could have answered my own question!

mcgivor · June 2019

DickyDck said:

I can reset to factory and start from scratch with no issues, both the installer and Schneider have had me do that several times. The only thing that I need to reset are the battery settings, and turn A/C coupling off... and the load shaving again.

Don't forget the frequency range, grid should remain within one hertz plus or minus of 60Hz , generator, if used ,a wider range is acceptable to account for reaction to loads, perhaps 55-65Hz may be a good starting point. Just an opinion.

DickyDck · June 2019

At defaults after a reset they are at 55/65 so I’ll leave them at that, I’ve used my generator one time just to test that it works and was strong enough to power everything, which one would hope a 11kw generator would, but seeing is believing so I had to give it a try! I like messing with things as some of you may have picked up on

Dave Angelini · June 2019

Yes we picked up on it and good luck, just give it time and think safety. It is a very hard thing to get a grid tie going on a hybrid. Most can't do it or never have tried. That goes for your installer also

tampasolar · July 2020

Most neutral damage IS in the meter box. Especially if you have an overhead drop to the meter. Very easy for water to drip down the feed cable and right center in the meter box. L1 and L2 are left and right of center. Neutral goes center between the meter blades for L1 and L2. Be very careful to try to repair a rusty neutral path -- 200 amps is ready to jump at you from either side.

Split Phase vs Single Phase confusion

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