Trace T240 Autotransformer.

littleharbor2
littleharbor2 Solar Expert Posts: 2,105 ✭✭✭✭✭
in Off Grid Solar & Battery Systems #1
Trying to figure out how useful this would be. On page 8 of the manual It appears to put out two legs to the 240 load. I see no mention of split phase output. My questions are, is the 240 vac output a single phase and only useful for a limited amount of items? Can it be wired into a split phase 120/240 vac. power panel?

T240 Manual 975-0001-01-02 Rev. B (unboundsolar.com)

2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,618 admin
    #2
    From your link:

    This should do it for you...

    Note, this assumes a TSW/PSW inverter with Neutral+Ground bond (either inside the inverter or inside your "main panel"--You may need to confirm where).

    The Ground Bonded Neutral is not needed for function--But follows NEC and is "required" for safety (long story about "floating" power systems needing Breakers on all connections, vs ground bonded neutral needing breakers on L1 and L2, none needed on neutral).

    For MSW inverters (modified sine/square wave), transformers don't really "like" that wave form (can cause transformers to run hot/waste power). Also, almost all MSW inverters cannot have a ground bonded neutral and a ground bonded negative (or positive) battery bus--That will "short out" the MSW inverter and let out the magic smoke (MSW inverters do not have electrically isolated AC output; TSW/PSW inverters have electrically isolated AC output and support N+G bonding).

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,105 ✭✭✭✭✭
    #3
    BB. said:
    From your link:

    This should do it for you...

    Note, this assumes a TSW/PSW inverter with Neutral+Ground bond (either inside the inverter or inside your "main panel"--You may need to confirm where).

    The Ground Bonded Neutral is not needed for function--But follows NEC and is "required" for safety (long story about "floating" power systems needing Breakers on all connections, vs ground bonded neutral needing breakers on L1 and L2, none needed on neutral).

    For MSW inverters (modified sine/square wave), transformers don't really "like" that wave form (can cause transformers to run hot/waste power). Also, almost all MSW inverters cannot have a ground bonded neutral and a ground bonded negative (or positive) battery bus--That will "short out" the MSW inverter and let out the magic smoke (MSW inverters do not have electrically isolated AC output; TSW/PSW inverters have electrically isolated AC output and support N+G bonding).

    -Bill

    Bill, thanks for your fast reply.. I would be using my Trace SW 4024.
     Maybe I cant see the forest for the trees, so to speak but I still don't see any terminology pointing to split phase output.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,902 ✭✭✭✭✭✭
    edited July 2022 #4
    The black box labeled 240 VAC LOAD IN BILL'S diagram ?  Remember happy hour is not suppose to start before 5pm :)
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,105 ✭✭✭✭✭
    edited July 2022 #5
    Dave Angelini said:
    The black box labeled 240 VAC LOAD IN BILL'S diagram ?  Remember happy hour is not suppose to start before 5pm :)
    No happy hour. Just got up from a siesta. Going to jump in the 90 degree sea fo a 1/2 hour or so. 
    So is there such a thing as 240 single phase using two hot legs not 180 degrees out of phase? I guess not. I kind of figured well pumps and such might be single phase. There is a well pump wiring diagram in the manual on page 9.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,618 admin
    edited July 2022 #6
    Think of each transformer winding as being a pair of 1.5 volt batteries connected in series... L1 to N is +1.5 volts, N to L2 is +1.5 volts again..with the two batteries in series you get 3.0 volts

    So see the "out of phase". Put the Meter black lead on Neutral (center tap). Measure Red lead to L1, you get -1.5 volts. Measure Red lead to L2, you get +1.5 volts... They are 180 out of phase (OK, DC does not really have phase, but you can see that L1 and L2, relatively to Neutral, are going in "opposite" directions (180 degrees out of phase).

    The technical term is 120/240 VAC 60 Hz "Split Phase" power... Split phase power is still single phase.

    To have multiple phase power, the angle between the two (or more) phases need to be shifted to non 0 / non 180 degrees. For example, 3 phase power is 120 degrees phase shift between phases. And with multiple phases, such as 3 phase, when you connect them to fields in a motor, you get a "rotating" magnetic field. Split phase power is a single non-rotating field that is flipping North/South.

    https://en.wikipedia.org/wiki/Three-phase_electric_power (example of first multi-phase motor--2 phase at beginning--Not split phase).

    https://en.wikipedia.org/wiki/Split-phase_electric_power

    Note that the transformers are "polarity sensitive"... They will put a DOT on each winding lead to indicated phasing/polarity:

    https://www.quora.com/What-is-the-dot-convention-of-a-transformer


    Does this help?

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,902 ✭✭✭✭✭✭
    #7
    Ah, I see where he is getting mixed up! Eureka !!!   A beer before Siesta ;)

    This may help you, the well pump is not going to get a neutral connection, it will just see the (2) 120 vac legs as 240vac.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,105 ✭✭✭✭✭
    #8
    Yes, Eureka it is!! That explains it perfectly. Thank you again Bill and Dave. At my ripe old age it sure feels good to learn stuff still. I'm going to print this page out and memorize it word for word.
     I think I'll have a beer now Dave.  B)

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • Ralph Day
    Ralph Day Solar Expert Posts: 1,022 ✭✭✭✭
    #9
    I had at 240 supplying 240v to my submersible water pump with an sw4048 inverter (120vac).  The pressure switch when "on'" would put power to the t240 and the pump, at the same time.  I once saw the display on the inverter hit 45amps (as high as it would display i beleive).  The old CRT type colour tv would go black and white with the display shrinking in a couple of inches from the edges of the picture tube.

    Who knows how much draw the pump and t240 actually drew on startup.  If you can, I'd suggest having a delay between t240 energizing and the load engaging.  

    The tv eventually died.  The inverter developed a fault (ac out relay I think) and was replaced with an Outback FXR3648
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  • Saggys
    Saggys Solar Expert Posts: 189 ✭✭✭
    #10
    I am using a T220 on the load side of my pressure switch to power our grundfos sq series well pump and it has been working great for the last year or so.
    The T240 requires 14 watt hours just to be energized, so less time on, more efficient.  The T220 is Trace's earlier autotransformer, which is slightly smaller than the T240.
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