rpm

[outback]

simply put,would anyone have a clue how fast a man could spin a dual rotor by hand [rpm] guestamation? i have no way of checking my rpm, my test coil will show any were from 2.5v just turning it easy up to 6.5v as fast as i can spin it by hand.the coils i had in mind,for this machine are 100 turns of 17 ga 12 mags 9 coils. the coil is being tested with only one rotor on.thanks for any input you might have

p.s that will be wired three phase.

[Hank]

I would venture a guess of 200-300 rpm spun by hand.

[LEXX]

under load or just free spinning, I found I could spin mine at around 200 RPM when free-wheelin, but put a load on and that goes WAY down.

LEXX

[outback]

well that surprises me i figured maybe 100 rpm. so taking those numbers how do i estimate my output was shootin for a 12 volt unit?thanks

[Norm]

Guys ...Guys! You can spend all that time on

these machines 12 mags 9 coils thats 100 turns

apiece or is that about 100 turns or

around 100 turns or I guess about 100 turns...

maybe some was 98 or 101 or 105??)

  It only took me about a half hour to take a

$1 calculator apart, trace the circuit to the

equals sign, drill 2 tiny holes on each side of

the trace circuit, wrap a lead wire around each

trace... solder them, a hole drilled thru the case, connect to a magnetic reed switch, a magnet

on whatever you are going to count, do the +1

thing on the calculator....spin away look at the

calculator and if you're doing 200rpm...it should

read about 33.

  It's also useful for coil counting...

anemometers, pedometer etc.

   http://www2.suite224.net/~peppysue/

  (the 88cent counter)

                 ( :>) Norm.

[DanB]

volts/rpm is a linear relationship... so if you know what you've got at 60 rpm you can predict the voltage at any rpm.  60, or 120 rpm is easy if you have a flashing digital clock around.. once around/second is 60rpm.  You can get pretty close that way.

Id guess 'as fast as you can' to be around 250rpm give or take some.  But... (that makes it easy) - if you have 2.5V @ 250 rpm from one coil...

then 3 coils in series (1 phase) would give you 7.5 Volts AC.

If you wire it into Star you'd multiply that X 1.73, so 12.9 VAC

then if we rectify that to DC you'd wind up with about 18 VDC.  (because AC is an approximation of RMS voltage and your rectifers will see peak voltage).

You'd lose a Volt and a half at the rectifiers so we'd expect about 16.5 VDC @ 250 rpm.

And that's with just one rotor on.  In some cases it seems like adding a second rotor will pretty much double things.  So perhaps 35 Volts or so @ 250 rpm.  It would cutin (12.5 Volts) at around 85 rpm.

#17 gage wire is really fine for 12 volts, you can't run much current through that or it'll get hot.  You should probably wind with much thicker wire and fewer windings.  I wonder what sort of magnets you're using?  For say.. an 8' diameter machine you'd probably  not want cutin speed much below 170 rpm (twice what youve got now) - so you could wind each coil with 50 turns of #14 wire - that would get a nice cutin speed for an 8' prop and you'd have much lower resistance (although it might still get too hot.. hard to say).

[jimjjnn]

Most calculators can count by 1 by entering a 1 X then press + and have your mag switch wired to = and it will increment by 1 each time the mag passes the reed switch

[jimjjnn]

Peppy,

Sorry about my previous post. Your way of calculator counting works better.

BTW, has anyone used the mags on the  rotor plate to trigger the mag switch for counting revs?

It may only trigger on either the S mags or the N mags. On older calculators that used mag switches, there were 2 mags with a gap between them to prevent switch chatter(didn't work all that great as switches got older).

[electrondady1]

i just had a friend count out the seconds while i turned it. or they can count a minet  while you count the revolutions.

[outback]

thanks dan for the input. would 17 ga and 21 ga give me about a 14 ga wire? those are 2in x1/2 in mags

[DanB]

two strands of #17 would be equal to 1 of #14.  

[outback]

thanks dan and everyone else for the support.i dont do much puter time but i like coming here.i have one daul rotor up now using tape drive mags very little useable power but have learned alot about the wind since i started.i dont have a digital camera but will try to get some pics up one of these days. i would like to show you my design to move the prop away from the tower.i gain about 4 inches that way.a miss is as good as a mile. thanks again.