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Forum Index : Windmills : HUMMER GENERATOR WHAT ELSE
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| tomqu7 Senior Member  Joined: 09/11/2012 Location: AustraliaPosts: 168 |
IF I HAVE A HUMMER GENERATOR ONLY WHAT WOULD I NEED TO GET A SIMPLE SYSTEM CONNECTED TO GRID WHERE CAN I GET THESE BITS IN AUSTRALIA |
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| tomqu7 Senior Member Joined: 09/11/2012 Location: AustraliaPosts: 168 |
how to figure out dump load if no load the windturbne self destructs if i am feeding into the grid is my system 240 volts How do I figure out how many dump loads I need? Now, to figure out how to appropriately size you dump load system, you need to ask yourself to simple questions: (1)What is the voltage of my system (12 volt battery bank, 48 volt battery bank, 200 volts?)? (2) How many amps will your wind turbine produce at maximum power? Once you know this information, you are ready to move on to the next phase. In these next steps, we have to do some math and use Ohm’s Law. Instead of speaking in generalities, let’s use a real example. Our example we will use the Wind 500 wind turbine charging a 24 volt battery bank. Step 1: What is the voltage of my system? Answer: 24 volt battery bank Step 2: How many amps does my Wind 500 make at maximum power? Answer: 26 amps (We know this by looking at the published power curve of the Wind 500) Step 3: The dump load system needs to be capable of dumping the maximum power of the wind turbine being used. Ohm’s law states that: Power = Volt x Amps. The voltage of the system is the battery bank voltage (We are going to use 29 volts which is roughly the voltage of a fully charged 24 volt battery bank). The amps is the current produced by the Wind 500 at maximum power (26 amps). Power = Volt x Amps = (29 volts x 26 amps) = 754 Watts Step 4: We need a dump load that can dump at least 754 Watts. We're going to use our 24 volt dump load resistors in this example. These resistors have an internal resistance rating of 2.9 ohms. Knowing that these resistors are 2.9 ohms, we need to figure out how much power this resistor will consume? Step 5: Calculating the power consumed by a 2.9 ohm resistor: Use Ohm’s law equation: Voltage = Current x Resistance and using simple algebra we arrive at the following equation: Current = (Voltage)/(Resistance) = (Battery bank voltage)/(Resistor’s resistance) = (29 volts)/(2.9 Ohms) = 10 amps Well, now we know at 29 volts (battery bank voltage) 10 amps of current will be used by one of these resistors. How much power is the resistor consuming? Easy, we know: Power = Volt x Amps = (Battery bank voltage) x (amps through resistor) = (29 volts) x (10 amps) = 290 Watts Therefore, 290 Watts will flow through one of our 24 volt dump load resistors. Important: At this stage, you need to make certain the dump load you are using is rated to handle 290 Watts at continuous duty or there could be a very dangerous fire hazard. The 24 volt dump loads can handle up to 320 Watts continuously so they will work fine for this application. Step 6: Setting up a 290 Watt dump load resistor to dump at least 754 Watts: If you go back and read Step 3, it says that our dump load system needs to be capable of dumping at least 754 Watts. How do we do this using a 290 Watt dump load resistor? Well, that’s easy! If we wire multiple 290 Watt dump load resistors in parallel, the dump load Wattage is cumulative. Therefore, we have this very simple equation: Total Watts our dump load system needs to consume = (290 Watts) x (# of 2.9 Ohm resistors we need wired in parallel) 754 Watts = (290 Watts) x (# of 2.9 Ohm resistors we need wired in parallel) And use simple algebra to solve: (# of 2.9 Ohm resistors we need wired in parallel) = 2.6 Well, our resistors only come in whole units so we cannot use 2.6 resistors. We have to round up as we need AT LEAST 754 Watts. Therefore, we need to wire three of the nm resistors in parallel. That will give us 870 Watts of dump load capacity. Now, we have appropriately set-up a dump load system for the particular wind turbine and battery bank used in this example. You can apply the same thought process above (Steps 1-6) for any wind turbine system. We hope this article helped you understand why dump loads are necessary for wind turbines |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Tom, and every one else, you must include a reference back to your source if you are going to post content that belongs to someone else. The post above is taken word for word from the Wind Nation web site, page http://www.windynation.com/articles/charge-controller/wind-t urbine-dump-and-diversion-loads-what-they-do-and-how-choose- right-s. Please read the forum guidelines. Apologies to Windy Nation. The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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