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rogerzipprogerzipp Registered Users Posts: 3
I have a 10kw windturbine by china hummer. I have a large dump load with it but the wiring they say is supposed to work with it won't hook up lugs to small. I'm trying to figure wire size to hook rectifier to dump load. I have 20 156ah batteries in series for backup.(recommended). Looking for wire size.
Also it came with a 240 inverter that I am going to hookup to resident but it only has 2 wire output. Without it being powered up I don't know what the voltage output is.  Considering you need 3 wires to hookup the  residents, I'm bet confused?

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  • BB.BB. Super Moderators, Administrators Posts: 32,027 admin
    Welcome to the forum Roger,

    I guess this is your turbine?

    http://www.allwindturbine.com/products_info/Hummer-10KW-Wind-Turbine-For-Farm-Used-228312.html

    240 VDC battery bank @ 156 AH @ 10-11 kWatts max output.

    I did not find any detailed manuals with a quick search... If you have a link to the design/installation manual, you can post it here.

    But just to take some wild guesses (rough sizing)... Say 11 kWatts @ 290 VDC (batteries charging/charged).
    • 11,000 Watts / 290 volts = ~38 amps
    Assuming the dump load is rated for 11,000 Watts, then you are looking at around 40 amps maximum current.

    You would need to look at the NEC (National Electric Code, or relivant code for your location), but as an estimate, I would take the 40 amps and multiply by 1.25 NEC derating for continuous electrical loading--A safety factor for circuits that can run for hours at rated current (breakers and wiring for North America are rated to not trip at 80% of rated load and will trip at 100%+ of rated load... 1/0.80 = 1.25).
    • 40 amps * 1.25 NEC derating = 50 Amp rated branch circuit
    NEC simplified wiring table:

    https://lugsdirect.com/WireCurrentAmpacitiesNEC-Table-301-16.htm

    From table, depending on what wiring temperature rating/type, you are looking at 8 to 6 AWG copper cable.

    Regarding the AC inverter... In much of the world, they have 230-240 VAC @ 50 Hz power to the home... Or they have 100/110 or other single voltage utility power (the link above says 110/220/380 VAC output). That is just two wires (L1 and L2, or L1 and neutral, depending if you have a ground bonded neutral or not). Assuming you have a pure sine wave (PSW/TSW) AC inverter, it may come with one of the outputs bonded to green wire/safety ground or they are expecting you do to that in the main breaker panel of your home)... Need more information to figure out what to do regarding neutral bonding.

    Assuming you are in North America, you typically have 120/240 VAC split phase @ 60 Hz power. That is three wires. L1 and L2 are the "hot wires" and the white wire is Neutral (typically ground bonded). L1 to N and L2 to N are 120 VAC. And L1 to L2 is 240 VAC.

    If your AC inverter has only two output AC wires... The native mode is L1 to L2 @ 110 VAC or 220 VAC or 380 VAC. There is no "neutral" (or transformer center tap) available.

    So your choices are to run 110 VAC loads, or 220 VAC loads... Or you need to add a transformer to give a neutral center tap. Not difficult to do, but you do have to get an extra transformer to create the third leg (Neutral) to run 120/240 VAC main breaker panel.

    Note that 10 kWatts into a 240 @ 156 AH battery bank is a lot of charging/load current:
    • 11,000 Watts / 240 VDC = 45.8 amps
    • 45.8 amps load/charging current / 156 AH battery bank = 0.19 = 19% rate of charge/discharge...
    Make sure you have some sort of battery bank temperature monitoring... For Lead Acid batteries, they can run hot/overheat if hit with that much charging current (and get into a loop where hot batteries, drop their bus voltage a bit, charger "sees" voltage drop as needing more charging current, and increase charging current/time, batteries get hotter, and melt down). Many larger charge controllers monitor battery bank temperature and reduce the charging voltage set point as the batteries get hotter.

    In reality, most wind turbines do not produce 100% of rated output for hours on end (in normal winds)--So you may get away with just a battery bank temperature alarm instead. The turbine does have braking (electromagnetic:"shorting of alternator output?", and hydraulic braking too--So you have three methods of controlling turbine output/RPM--Always a good idea).

    Those are my rough guesses at first pass answers to your questions.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • rogerzipprogerzipp Registered Users Posts: 3
    Thanks Bill, yes this is my W/T and I'm in Tx and it does have all the over temp, auto braking etc. Features. I'm still waiting ti find out from manufacturer on the wiring they sent me for the dump load because it is only a 10 or 12 way wire, which I differently can't by off on. Looking to go 4awg for coverage. It is only 2 wire out of inverter but since I'm not running I can't check output of inverter. Thank you 
    Roger 
  • rogerzipprogerzipp Registered Users Posts: 3
    Thanks Bill, yes this is my W/T and I'm in Tx and it does have all the over temp, auto braking etc. Features. I'm still waiting ti find out from manufacturer on the wiring they sent me for the dump load because it is only a 10 or 12 way wire, which I differently can't by off on. Looking to go 4awg for coverage. It is only 2 wire out of inverter but since I'm not running I can't check output of inverter. Thank 
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