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[Dan the Handyman]

  Hello to all,

 I have been reading this web site, and this forum for a while. Thanks to all for the advice and hints, so I thought I'd join up!

 Now to my question; I have a 48 volt stepper motor attached to a two bladed 60" prop. The prop has taper, but no twist. In a good wind, maybe 15 mph I get 22V and 150ma. What I am wondering is if I will fry a 6V battery directly connected to the rectifiers.

  Thanks in advance for any help.

 PS. The rectifiers are not a voltage doubler

 Dan

[ghurd]

Not enough information to answer the question.

The battery would have to be small for 150ma to fry it.  It could potentially fry 4 AAs but it won't fry a 6V 10AH from a young kid's Barbie car.

From FAQs concerning 22V into a 6V battery,

http://www.fieldlines.com/story/2004/6/2/33325/13962

The prop is way too big.  Way WAY too Big.

It sounds like the 22V and 150ma are open and short.

A 48V stepper should make over 22V at a relatively low RPM.

The 150ma sounds like the stepper is small for a motor.

Might try something like 30" diameter.  I have a feeling you will be much happier with the output.

I would like a few more details to satisfy my curiosity.

Mainly the shaft dimensions and how a 5' blade was hung on it.

G-

[Dan the Handyman]

 Ghurd,

 Golly Jiminy cricket! First post, and one of the masters answers:)

 Anyway, the battery is a SLA 4AH. And,yes Iknow the prop is too big for the motor. It was originally for a DC motor taken from an old Betamax that would produce lotsa watts on the bench, but not much on the pole.

  It is what I have. Great rpm's, but not anything I would recomend.

 My concern is whether the battery will go kablooey with the output.

 Also, since you asked, the prop is attached to the motor with Liquid Nails.This is only an experiment, so as to understand how this stuff works. A Chispto style and a Piggott wind generator are on the way.

 Thanks again for the response. I look forward to your next project. And thanks again for input

 Dan

[Dan the Handyman]

Also the shft is probably 5/64" attached to a gear aproximately 5/8" diameter

 Dan

[ghurd]

Thanks Dan,

First, do not think I know everything.  I simply have down-time to answer some common questions.

I do not believe 180ma Isc in 15MPH will fry a 4AH in most daily wind conditions.

You do Not have great RPMs for something like that motor.  Make some shorter blades.

The 5/64" shaft is supporting a 60" prop in a 15MPH wind?

Something is either wrong or very lucky.

I would take it down ASAP.  Not remotely safe.

I still use an old formula for small things, and I only do smaller things.  

Max prop diameter = 100 x shaft diameter.

A 5/64" can take an 8" diameter prop.

I would not put a 60" prop on a 3/8" shaft.

G-

[Dan the Handyman]

  Thanks G,