OVERVOLT Protection

Discussion in 'General Questions' started by targabill, Jun 26, 2014.

  1. Hi, Already burned out one Sun 1000G WDL..

    Does anybody have a suggestion for a pre-GTI protection device???

    More specifically:
    0v DC - 25v DC outputs signal to activate a relay (Solid State Relay)
    25v DC - 55v DC output a different signal to close a different relay, normal operation
    above 55v DC output yet another different signal to close a relay to DUMP...

    seams like something should exist?? Over/under volt protection ??

    thanks much,
  2. TomT

    TomT WindyNation Engineer

    What is the first relay for?
    We just run one to go to dump at 55 volts. With the GTI still connected. No resistor connected to the dump terminals.
    If you have really gusty winds this is what you have to do for your system to survive. Mine has been going strong for three years. With a few recorded gusts from 15 right up to 65 mph.
    You will have to set one storm out and check voltages. But usually 2 ohms will do the the trick of bringing the turbine under control. Any lower and the turbine will drop rpm too fast. It is also hard on the turbine. If too low you have the magnets trying to hold the turbine from turning. And when it slips from pole to pole it makes alot of vibration and noise.
  3. to capture some low wind stuff...
    Is there a device to do this, maybe adjustable voltage control ?
  4. TomT

    TomT WindyNation Engineer

    The one I sell has just one trip point. It can be used for more stuff. But I also use them for overvolt. It is adjustable 0-100 vdc. It is capable of running a golf cart relay. That is what I use now. It also has an adjustable time delay on the off cycle and 0 to on at the trip point. Most of the ones I looked at had a 3 sec to on delay and with my wind it was too much. I also use a 2 ohm wire wound resistor for the dump. It slows the turbine and still makes power while doing it. Any lower and it kills power production while doing so. Any more and the voltage runs away. So start with 2 ohms and adjust from there.
    targabill likes this.
  5. TomT

    TomT WindyNation Engineer

    We hook it at the DC terminals of the GTI. I run mine from a battery. Just incase the power goes out. Should not need three relays. If you use the bosh 40 amp ones. I would suggest 3 or 4 of them. That is why I redesigned the board for golf cart relays. Had to increase the trace width and use a different mosfet. That way you only need one.
    targabill likes this.
  6. HI Tom, Thanks for the info.. I am very interested in your over volt protection device.. Do you have a diagram or schematic of some kind.. Even written on a napkin of your hook up. I do not want to burn up another GTI...

    This is what I think I'm hearing... Voltage comparator on GTI dc inputs, when it see's a voltage greater then 55vdc it switches a signal on (or sync to ground) and closes a relay. Is this a SSR? Not sure what a golf cart relay is? When this relay is closed it does not disconnect the GTI but adds your 2 ohm resistor in parallel to it to share the current. Does it oscillate on and off? once you add the load and slow the turbine the voltage will drop...

    Also, the resistor I have is the recommended 3ohm 1500w single resistor..
    Not sure what you mean by "Should not need three relays. If you use the bosh 40 amp ones. I would suggest 3 or 4 of them. That is why I redesigned the board for golf cart relays. Had to increase the trace width and use a different mosfet. That way you only need one."

    One relay would just tie the + side of GTI to a parallel dump resistor. When you say 3 or 4 of them, you mean 2 ohm resistors is parallel(which lowers the resistance).

    Anyway, to start how much are you asking and do you have one available...?
    thanks much... Bill
  7. TomT

    TomT WindyNation Engineer

    The picture of the new board is here scroll down to see it.
    Depending if you use Bosch relays you may need more than one. I had three 40 amp ones for mine till I went to HD relays.
    I only use one 300 watt 2 ohm wire wound resistor for each turbine.
    The board monitors the GTI voltage and trips the N/O Relay to connect the POSITIVE terminal of the GTI to the resistor and the other end of the resistor to ground.
  8. TomT

    TomT WindyNation Engineer

    Did you get my message?
    Are you on Youtube?
    I am TomT342
  9. I am, targabill, but i did not see a msg..
    I just bought a few 40A SSR off ebay but I'm still looking for a voltage compare switch.. I see a few very cheap one's on ebay that switches a NO/NC relay but I cant seam to find out if it will work at 50-55vdc... It uses an LM393 voltage comparator..
    I was also looking at the wind speed switch from inspeed but it a bit costly..
    Just got my new 1000w GTI in today, now wind so I can check it out..

  10. TomT

    TomT WindyNation Engineer

    I have been selling mine for $60 and I pay postage.
    But if you find a cheaper version that will work go ahead and try it.
    Real sticker here is that they should not have a delay before they trip the relay.
    Also good luck with the SSR's. I fried all mine. That is why I am back to using continuous duty mechanical relays.
    Also go to the top of the page and click on the inbox. Then you should see my message.
  11. TomT

    TomT WindyNation Engineer

    Now for a more or less update.
    If you have a wind turbine YOU NEED OVER VOLT PROTECTION !!!!
    Whether you are Direct Connect to batteries or use a Classic with a Clipper or Grid Ties.

    1. Direct Connect - A controller that will use a relay and resistors to burn off battery voltage if it gets too high. This must be designed to also take care of any power coming in at the time from the wind turbine.
    2. Classic w/Clipper - Works fine as is. But if you have a failure what then. You need a separate dump load for safety of the turbine.
    3. Grid Tie - Also needs a separate dump load do not use the terminals. The manufacturer is now giving out resistors that are 3-5 ohms and look like this.
    Screenshot at 2018-01-27 12-00-59.png
    These have a problem as they heat up the resistance goes down it glows bright and puts off lots of heat. It is basically an infrared heater.
    It will not keep a turbine from over speeding and burning your system up.
    Grid Ties have 3 algorithms and disconnect while switching between them and during large gusts will disconnect the turbine then try and reconnect every 5 secs.
    Any other type and lower resistance will fry the dump load mosfets.


    You need a comparator voltage switch.
    100% duty cycle relay.
    (2) .70-.74 300 watt wire wound resistors.

    Screenshot at 2018-01-27 12-11-42.png
    Hydrogen Appliances has them.
    Screenshot at 2018-01-27 12-15-39.png
    Windy Nation Has them.
  12. TomT

    TomT WindyNation Engineer

    The above post is for DC now for ac side we use SCR's for the dump load relay.
    I found mine on EBAY. You will also need three resistors. One for each phase.


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