windgat wrote:I think single phase will cause quite a vibration - it means there are points in the rotation where there is no resistance. Perhaps you can use three phases to three separate heating elements?
I can work-out the resistance of the coils and thereby the anticipated heat loss. I'm trying to keep it to 2 - 2.5 Watt per coil. So far. 0.8mm wire remains a posibility.windgat wrote:In fact the other day in a storm I saw 19amps coming into the batteries at one point. Question is at what current the wire would be damaged or melt... for that test I would need a more powerful motor. Also, in a high wind there is a lot of cooling that is hard to duplicate on the test bench.
I assumed that 240V would be the peakvoltage. The effective voltage (used as an AC power source) would then be 167V. Therefore, 6A is correct.windgat wrote:You want to use 0.8mm wire, which makes the melting point that much sooner... there again (I just read yr post again) if you operate at 240V, then 1kW is only 4 amps.
But there is another matter to consider. Something you made me think about doing that "average windspeed" exercise.windgat wrote:Overall I like yr idea! No more 'cutoff voltage' below which no power is extracted from the wind.
WOWwindgat wrote:I think you may get 1kW out of the design just by doubling the blade length (to 2m).
Thanks for those figures. It will help a lot.windgat wrote:So for example, for 50x25x12.5mm magnets of grade N35,90rpm gives 0.302 x 88 x 90 = 23.91V (measured value = 24V) (with std deviation of 0.00109).
Was thinking the same thing. Just look at all the adverts on the Internet about what you can all do with a wind turbine . . .windgat wrote:PS: I love the way the industry commonly calls something '500W blades' for example, without mentioning the wind speed .....
windgat wrote:What plastic do you recommend that's practical for home builders?
I have used two part polyurethane resin, which is liquid and when mixed sets in about 30 min. Perhaps an idea is to make one blade from PVC, and use it to make a mould for another kind of (pourable) plasitc?
I was thinking of two stators @ 12 positions each, single phase.windgat wrote:Some comments:
12 magnets and 24 coils? Is that a single phase?
Hmmmm . . not sure. The induction is voltage, NOT current, which depends on the area of induction covered by the coil (independent of shape)windgat wrote:Circular coils.... its only the up and down vector components of the windings that make current, so wouldn't circles mean less current compared to wedge shaped?
I think you're right.windgat wrote:34 turns of 0.8 seems like very small coils - I think you could easily fit more copper in there.
Didn't consider this.windgat wrote:Your tip speed ratio is 3.7? How many blades? That seems small for a 3 blader...
The formula =: E=-Nd?/dt, in which E= induced voltage, N= number of windings, ?= magnetic field in Weber.windgat wrote:Circular coils.... its only the up and down vector components of the windings that make current, so wouldn't circles mean less current compared to wedge shaped?
Now I thought I understood you. My mistake. Please explain: What is "tip speed ratio".windgat wrote:Your tip speed ratio is 3.7? How many blades? That seems small for a 3 blader...
Greystoke wrote:Hmmmm . . not sure. The induction is voltage, NOT current, which depends on the area of induction covered by the coil (independent of shape)
I didn't mean that. I meant circles or rectangles. It's the area that counts. The bigger the winding, the greater the fluxchange, the higher the induced voltage.windgat wrote:... If you are sure that shape is unimportant, try imagining winding the coils in the shape of clover leaves...
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