So, I'm starting to think about how I want to do my diversion load. Somewhere on this board, I recall how wattage of WH elements dropped off sharply with lowering voltages. It got me wondering if this fact would make it ideal as a speed controlling dump load.
Say I would have a 120v, 1500w water heater element connected to the wild DC out of the rectifier. During low winds and turbine voltages, wouldn't the resistance of the element prevent current from flowing, and thereby allow the turbine to freewheel? And, as speed and voltage increases, so would the current to the element? The faster the wind and higher the voltage, the more "hungry" the element becomes, taking up the energy, no? Eventually, wouldn't the element overpower the windmill and cause stalling in higher winds, correct?
Below is a chart of my basic calculated output numbers. (disregard the amps and watts figures, as they are intended for battery charging) The voltage would still be a bit low for a 120v element and reach it's wattage potential. Perhaps paralleling a second element would be a good idea. (if my knowledge of Ohm's Law is correct, that should cut resistance in half)
MPH RPM rectified open VDC Amps Watts out
- 6 108 025.71 000.0 0001 (cut - in)
- 1 143 034.04 012.8 0330
- 5 178 042.38 025.7 0659
- 0 213 050.71 038.5 0989
- 4 248 059.04 051.3 1318
- 9 283 067.38 064.1 1647
- 6 321 076.42 078.0 2005
(furling/furled by this point. beyond this is speculation)
- 1 356 084.76 090.9 2334
- 5 391 093.09 103.7 2663
- 0 426 101.42 116.5 2992
- 4 461 109.76 129.3 3321
- 9 496 118.09 142.1 3651
I don't know, sounds too easy. I must be thinking wrong here. OK, awaiting return fire.
Rod