PMA checkout?

troybrownrigg
troybrownrigg Registered Users Posts: 18
What is the common way to test the a windy nation three phase unit! The senerio is that the battery bank is at 13.2 VDC and the charge controller from beawindhog.com has a cut off of 14vdc and a cutin at 13vdc. The batterybank is currently charged by 640 watts of ul solar panels. What I'm thing is the charge is going to the 1000 watt dump unit from Missouri wind.

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Testing a 3 phase pma?

    Are the battery charging set points adjustable/temperature corrected?

    14.0 volts is usually pretty low for battery charging--typically, you would want 14.4 to 14.8 (AGM will be a bit lower). After the battery is charged (typically hits set-point and is held for several hours), then you want the charge controller to hold the battery at "Float" around 13.2 to 13.8 volts.

    Dump controllers do not have near as nice voltage/charging control as a typical solar charge controller... Assuming most of your charging is done by solar and not wind--I probably would set the dump controller to "turn on" at (for example) 14.8 volts and the Absorb voltage for the solar controller set at ~14.4-14.6 volts...

    Normally, the solar charge controller will properly 3 stage charge the battery bank and the shunt/dump/diversion controller would turn on only when the wind is blowing hard and the bank is near full...

    Others here may have better suggestions (I do not have any wind or off-grid power at my home).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • troybrownrigg
    troybrownrigg Registered Users Posts: 18
    PMA checkout?

    How does one check out the ouput of a three phase pma?
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: PMA checkout?

    Simplest is to use a three phase diode bridge to rectify into DC power...

    You could use an AC current meter on each leg from the motor (or an AC Current Clamp Meter). If the motor has a broken connection--only two of the three legs will be carrying current (of course, you have to have some sort of load on the motor--three resistors, three filament lamps, a three phase diode bridge connected to a battery/DC load, etc.).

    You could sort (connect) all three output wires together and measure the current from each (basically Isc -- short circuit current)--but be careful to not spin it too fast--you can probably overheat the PMA or its wiring by driving a dead short.

    What is it you wish to do with motor? Make a wind turbine?

    A three phase PMA is basically a car alternator that uses permanent magnets instead of slip rings and field coil/armature.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • troybrownrigg
    troybrownrigg Registered Users Posts: 18
    Re: PMA checkout?

    It is a windy nation 750 model I just want to verify if it has an output, as the slipring may be defective!
  • troybrownrigg
    troybrownrigg Registered Users Posts: 18
    Re: Testing a 3 phase pma?

    Reading my solar charge controller info 14vdc is the cut off, and 11.8 is cut in or resume. I've never seen the system above 13.8vdc or below 12 vdc. The system has been what I consider running very efficently. I may not have enough wind for the windy nation model to kick in! or the system is already topped off.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: PMA checkout?

    Hard to test them up in the air, because as the wind varies so does the output.
    If you can get it on the ground and spin it with a motor (or a big box fan blowing a steady stream across the blades) you can check the Voltage and current from each winding.
    Does this model send 3 phase AC through the slip ring, or does it rectify it to DC first? It's important to check the windings output individually to make sure each is intact and then compare to the DC out - in case there's a blown rectifier.

    It's a pain in the anatomy, but; eliminate the wind speed variable, check output at each "stage" along the way, and you'll see where (if) any power is being lost. Checking the resistance across the slip ring connectors as you swivel the mount is a good idea too; in case there are any spots where good contact is lost.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: PMA checkout?

    Note: I merged the two similar threads and moved the result to the wind power section just to keep things organized.
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Testing a 3 phase pma?
    Reading my solar charge controller info 14vdc is the cut off, and 11.8 is cut in or resume.

    WHAT:confused: Your controller allows battery voltage to drop to 11.8 before it kicks back in and starts charging again:confused: Wow! I'd never run my batteries down like that. If your numbers are right, then in my opinion your controller is a real battery killer:cry:
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Testing a 3 phase pma?
    Reading my solar charge controller info 14vdc is the cut off, and 11.8 is cut in or resume. I've never seen the system above 13.8vdc or below 12 vdc. The system has been what I consider running very efficently. I may not have enough wind for the windy nation model to kick in! or the system is already topped off.
    There is something wrong here... 11.8 volt cut-in hardly makes sense for a solar charge controller... Typically, if the battery voltage falls below ~12.7 volts (full charge resting voltage at ~77F), the charge controller will assume the battery is under load or less than full charged and start the charging cycle over again.

    13.8 volts is just about the minimum voltage I have ever seen for charging--and that was on a car/pickup alternator where the discharge is short and shallow (engine cranking).

    Unless you have some other battery chemistry--You should be looking at ~14.2-14.4 volts (AGM/Sealed) minimum or even as high as 14.5-~14.8 volts (flooded cell) for quick/productive charging cycles.

    Around 13.2-13.7 volts is just "float charging"--keeping a battery charged, but not over charged (driving off hydrogen gas, oxidizing the positive grid/plats, etc.).

    How have you been estimating the state of charge of your battery bank?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Testing a 3 phase pma?
    WHAT:confused: Your controller allows battery voltage to drop to 11.8 before it kicks back in and starts charging again:confused: Wow! I'd never run my batteries down like that. If your numbers are right, then in my opinion your controller is a real battery killer:cry:

    I suspect a typo; his first post says "cutin at 13vdc". Maybe it's 13.8 VDC. Anything under 12.5 would be ruinous.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: PMA checkout?

    I believe we are talking about two charge controllers... The first is a wind diversion controller. And this last one is his solar charge controller.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • troybrownrigg
    troybrownrigg Registered Users Posts: 18
    Re: PMA checkout?

    That's correct two charge controllers, the thought is that the system is maintained where the wind charge controller may have very limited use. Due to the fact if the battery bank is charged the wind controller will just dump to produced current. Which I currently have no amp meter monitoring it. I've got a shunt measuring the current going to the battery bank, but if it maintains itself in dump mode there's nothing to measure.
  • troybrownrigg
    troybrownrigg Registered Users Posts: 18
    Re: Testing a 3 phase pma?

    I've been watching three amp/ volt meters. sometimes I've doubled checked with a meter. I've never seen the system below 12.2 vdc, and never above 13.8. seems to be rather stable! the battery bank is about 800 amp hours.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Testing a 3 phase pma?
    I've been watching three amp/ volt meters. sometimes I've doubled checked with a meter. I've never seen the system below 12.2 vdc, and never above 13.8. seems to be rather stable! the battery bank is about 800 amp hours.

    The point is that if you're going to charge deep cycle batteries properly the Voltage should go up to 14.2-14.8 and stay there for what is known as the Absorb cycle. As per the battery FAQ's: http://www.windsun.com/Batteries/Battery_FAQ.htm#Battery%20Charging

    Battery Voltage ranging from 12.2 to 13.8 is not necessarily a sign of a healthy charging system. You can maintain that "stable" Voltage for a long time - while the batteries sulphate, decrease in capacity, and die before their time. An 'AAA' battery and a 'D' cell are both 1.5 Volts, but they don't have the same power curve. That 800 Amp hour battery bank should have something around 1200 Watts of charging power available to it.
  • troybrownrigg
    troybrownrigg Registered Users Posts: 18
    Re: Testing a 3 phase pma?

    My next part of the project was to increase the 640 watts of panels to 1280 watts, I'm not pulling much more then 360 watts currently, ( a dehydratrator for food, electric fence box and a couple of lights at night. My plan was to have about 1960watts of solar and a battery bank of 2700 amp hours. Later as the project expands I'll be running my well pump off of the system the aims 8k/16/k unit operates it with no problems. (already tested it)
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: PMA checkout?

    Hate to sound like a broken record but ...

    When you need that much power (16 kW hours potential) you really should be increasing the system Voltage. Trying to manage a 12 Volt 2700 Amp hour battery bank will be a chore, and the DC current levels involved in powering things like the water pump are very high - and inefficient.

    The water pump will work better on a pure since inverter, and the AIMS design is not a good one in my opinion (parallel inputs to handle the huge current potential are a bad idea).

    I've said my piece; you can heed or ignore as you wish. It's your money, not mine.