Series Resistance

Discussion in 'General Questions' started by TomT, Nov 27, 2010.

  1. TomT

    TomT WindyNation Engineer

    OK now for some good news .
    Waiting for some wind to see how this will all work out. I upgraded my wire from the rectifier to the battery from 8ga to 4 ga. and guess what? That dead spot that my amps will not go up till the wind really picks up got bigger again. :evil:
    So after thinking about it for a really long night. It dawned on me that maybe adding resistance between the rectifier and the battery would help. :idea: So today I did this.
    [attachment=0:4qe3qfjc]SeriesSprings.JPG[/attachment:4qe3qfjc]

    They are 2 14ga 1/2inch diameter one foot long springs stretched to about 3ft. in series. The first one jumped my volts at the turbine from 14v to 18v. Very interesting. :) The second one added on now the turbine starts at 14v and as the amps come up the turbine goes up to 24v. :D This happens around 5 amps. At 10amps it is still at 24v. It also took my cut in down a little.This is just for testing. Ohms is under 1. So if anyone wants to try it. I am thinking a 12v 300w dump load resistor at .73 ohms should do the trick.
     

    Attached Files:

  2. TomT

    TomT WindyNation Engineer

    Forgot to add this.
    This is without the series caps.
     
  3. TomT

    TomT WindyNation Engineer

    Also since the power curve of the 24v scale is much better that is why I went with that voltage level. Trying to keep the ohms down as not to waste too much power. While boosting the power output.
    If you do not want to waste money on springs for the test setup. Go down to the local dollar store and buy paper with spiral metal binders and take the metal spirals out and use them.
    Other idea is once you find out how much resistance you need move the rectifier down the line to match the ohm value.
    This will probably be only good for people that are direct connect to 12v batteries.
    My cut in went from 6mph down to 4.5mph and that flutter in the 1 amp range went away.
    So now have to wait for some wind so I can move the clamps around and find the best spot. Just know right now that 2 springs cut out the braking effect and the current movement is smooth up and down without a big increase in blade speed. Running the series caps there was a lot of turbine noise and some times it ran soo fast it was scary. :shock:
     
  4. TomT

    TomT WindyNation Engineer

    BAD NEWS....... :eek:
    Got good wind just now and this is a loser. :cry:
    Below 10 amps it is a winner. The amps will not go above that and just goes to heat. Great thought but it does not work. Sorry bout that.
     
  5. timber

    timber WindyNation Engineer

    All may not be lost Tom, could you devise a way to use this at low wind speeds and cut-out at higher wind speeds?

    I don't quite have my head wrapped around how adding resistance can give you a gain in power, I always thought the goal was to get as close to 0 resistance as possible between the battery and rectifier. I must be missing something, I guess it's the relationship of amp draw from load vs. cut-in speed that I don't understand.

    Hope you get the system dialed in to run smooth.

    Dave
     
  6. TomT

    TomT WindyNation Engineer

    Adding the resistor to the back side of the diode creates a voltage against the diode. Then it will raise the voltage at the turbine to get the diode to conduct again. But the resistor goes the wrong way. :( Resistance goes up as the resistor heats up faster than the voltage climb. So it basically raises the potential against the diode at a point where is will only conduct so much current thru. Which in the long run could damage the turbine. Voltage gets high and current in the turbine would too till it melts if the wind got high enough.
     
  7. timber

    timber WindyNation Engineer

    Hi Tom,

    Thanks for explaining what is going on regarding the resistance.

    I was quite interested in your use of caps also, I first read about possibilities with them at Fieldlines a few years back but I never followed up on the results of testing of them. Any luck there?

    Thanx,

    Dave
     

Share This Page