pma wireing

Discussion in 'General Questions' started by irv, Apr 2, 2010.

  1. irv

    irv WindyNation Engineer

    there are no instructions with the 500 watt pma from windy . does it matter how the three wires from the pma are wired to the rectifer that comes with it ?
    and how do you check the ac voltage from the pma ?
  2. okiezeke

    okiezeke WindyNation Engineer

    The 3 phase AC output from the PMA can be wired to the rectifier in any order. The voltage output of the PMA could be measured with a meter on AC volts in relation to ground, but it might make more sense to go by the DC output of the rectifier. In order to charge batteries the wind gen DC voltage must be higher than the battery bank voltage. A 12 volt deep cycle lead acid battery bank needs 14.3V or so to charge and 15.1V to equalize. DC voltage will be different than AC voltage, even though not by much.
  3. windyguru

    windyguru WindyNation Expert

    okiezeke is totally correct.

    I also prefer to measure the DC voltage (after the rectifier) because it is the voltage the battery bank will "see". And even if you are using a grid tie inverter, the inverter will convert the rectified DC voltage to single phase AC. The 3 phase AC voltage and DC voltage will be almost the same in this situation but they will definitely be different values.
  4. BeachBum

    BeachBum WindyNation Engineer

    I was a bit confused with the wiring too. If the order doesn't matter, why are the wires labeled U1, V1, & W1?
  5. TomT

    TomT WindyNation Engineer

    Those wires are marked for the factory when they built it. They are marked just for their reference. Each wire puts out AC at a different phase of the ac cycle. So after it goes thru the diode rectifier it is a smoother DC voltage. That's why the wire them with multi phases. Other wise we would have to add a circuit on our end to smooth out the DC after the diode rectifier. Hope that helps.
  6. BeachBum

    BeachBum WindyNation Engineer

    Thank you again. Other than just referencing the wires, I figured there must be another reason why the slip ring and PMA wires were labeled this way, possibly a different application than charging DC batteries.

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