Playing with wind power

[BrianG]

A higher kv will generate more voltage for a given rpm, so I would go with that. And, I wouldn't worry about stalling the motor because charging a battery is not nearly as much load as shorting the motor leads. The battery charge current is "regulated" by the current battery voltage and any inline resistance or circuitry. And, you might have to gear up the motor because a windmill does not spin very fast and these motors will have more output at higher rpms. Maybe an outrunner would work better in direct drive?

[J57ltr]

Wasn't really thinking direct drive I was thinking 4:1 to the motor. I have a bunch of prototype parts from when I was developing a small coonveyor for our company so I have a bunch of .080" pitch belts and some 60 tooth 1/4" sheaves and belts and 15 tooth sheaves that are bored to 5mm (our motor uses a 5mm shaft too). I think the gearboxes would have too much drag, and the only ones I have are about 30:1 and another that's about 100:1.

I swear that at the same RPM the lower KV motor had a higher voltage out.

This is going to be a pretty small unit about 16" tall and about 12" in diameter. Just for testing too see what I can do just with what I have laying around.

Jeff

Keep the ideas going!

[_paralyzed_]

Originally Posted by J57ltr

Wasn't really thinking direct drive I was thinking 4:1 to the motor. I have a bunch of prototype parts from when I was developing a small coonveyor for our company so I have a bunch of .080" pitch belts and some 60 tooth 1/4" sheaves and belts and 15 tooth sheaves that are bored to 5mm (our motor uses a 5mm shaft too). I think the gearboxes would have too much drag, and the only ones I have are about 30:1 and another that's about 100:1.

I swear that at the same RPM the lower KV motor had a higher voltage out.

This is going to be a pretty small unit about 16" tall and about 12" in diameter. Just for testing too see what I can do just with what I have laying around.

Jeff

Keep the ideas going!

I'm really curious about the small sheaves and belts you speak of. I've been toying with the idea of a belt drive rather than a traditional spur/pinion. Have any links or pics?

[J57ltr]

Stock Drive is a place that carries them. They are called Timing pulleys, I guess I just use sheave for anything that uses a belt. http://www.sdp-si.com/web/html/drivesystems.htm

I can’t pull up anything on their site right now but I use a 3/8” wide .080” pitch Kevlar reinforced belt. A 15 tooth drive pulley that we bore to 5mm and a 30 tooth that comes ¼” bore and, is just under 1” in diameter we bore it to 3/8”. The belts are strong but would probably wear out fast in a RC think belts run about $6 the larger pulley runs about $15 and the smaller ones about $9. Of course that’s just a 2:1 ratio they also have plastic pulleys and ones with larger teeth (that’s usually the first thing to go). There are some others but I’ll have to check at the office.

Jeff

[Patrick]

Originally Posted by BrianG

A higher kv will generate more voltage for a given rpm

I thought some companies found the motors kv by finding the rpm needed for the motor to put out 1 volt. I don't remember who said that, but it was on rcm. Could take a while to find in a search, so I can't be bothered looking

[J57ltr]

Hmm, I am sure it's the other way around a motor will spin X rpm per given volt. Generating power and producing power seems to be 2 totally different results. I'll give it another try later tonight.

Jeff

[BL_RV0]

Originally Posted by BrianG

A higher kv will generate more voltage for a given rpm,

I think you got it backwards there Brian...