Need help with nitinol motor Bribe offered

HI All. I am developing a motor using super elastic nitinol wire and have problems. Picture at: http://www.pacificsites.com/~snyder/motor.jpg The most frustrating problem is joining the wire together. I bought some tiny stainless steel tubing from Ebay. The idea is to use this as a sleeve and solder/braze it together. It hasn't arrived yet. I have been unable to find small high pressure crimp fittings. The second problem is the wire slipping on the pulleys. I will send anyone coming up with a solution to either of these problems a piece of wire to play with, assuming it is something I can use. Wire description at: http://www.pacificsites.com/~snyder/Ebay/Flexinol%20Test%20Data.htm This wire has a transition temp ~100C. This helps resolving the cooling side. The heating side can be easily insulated with cheap materials(styrofoam). I am hoping to put this on a bicycle and operate with solar power. Any comment/suggestions are welcome. Thanks in advance. Larry

Larry Snyder wrote:

HI All. I am developing a motor using super elastic nitinol wire and have problems. Picture at: http://www.pacificsites.com/~snyder/motor.jpg

Are those pulleys on a common shaft? Please describe further...

The most frustrating problem is joining the wire together. I bought some tiny stainless steel tubing from Ebay. The idea is to use this as a sleeve and solder/braze it together. It hasn't arrived yet. I have been unable to find small high pressure crimp fittings.

Be careful. Your joint may wind up a lot stronger than the wire. It needs to be only *as* strong. Will the heat change the metallurgy to the point of weakening?

The second problem is the wire slipping on the pulleys.

Try a small 'V' shaped groove lathe cut into the pulley face. The wire should ride in the groove on it's two sides. That will double the contact area. I call it Twin Tangental Touching (TTT), mainly 'cause I couldn't resist the alliteration.

I will send anyone coming up with a solution to either of these problems a piece of wire to play with, assuming it is something I can use. Wire description at: http://www.pacificsites.com/~snyder/Ebay/Flexinol%20Test%20Data.htm This wire has a transition temp ~100C. This helps resolving the cooling side. The heating side can be easily insulated with cheap materials(styrofoam). I am hoping to put this on a bicycle and operate with solar power. Any comment/suggestions are welcome. Thanks in advance. Larry

mike
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"Larry Snyder" wrote in message

HI All. I am developing a motor using super elastic nitinol wire and have problems. Picture at: http://www.pacificsites.com/~snyder/motor.jpg The most frustrating problem is joining the wire together. I bought some tiny stainless steel tubing from Ebay. The idea is to use this as a sleeve and solder/braze it together. It hasn't arrived yet. I have been unable to find small high pressure crimp fittings. The second problem is the wire slipping on the pulleys. I will send anyone coming up with a solution to either of these problems a piece of wire to play with, assuming it is something I can use. Wire description at: http://www.pacificsites.com/~snyder/Ebay/Flexinol%20Test%20Data.htm This wire has a transition temp ~100C. This helps resolving the cooling side. The heating side can be easily insulated with cheap materials(styrofoam). I am hoping to put this on a bicycle and operate with solar power. Any comment/suggestions are welcome. Thanks in advance. Larry

HI All. I posted this on several newsgroups and got a lot of responses. I would like to thank everyone for their input. The answers that I like are: capstain/multiple turns around pulleys use tubing for guide and spot weld grooving pulleys for more surface area crimp fittings from fishing supply store idlers/belts to apply extra pressure on pulleys Answers I didn't like: coating pulleys with nonslip stuff- wire pressure too great. will fail too fast. I have notified people with the above ideas and will offer wire only for some other ideas. Thanks for your interest. Larry

"m II" wrote in message

Larry Snyder wrote:
HI All. I am developing a motor using super elastic nitinol wire and have problems. Picture at: http://www.pacificsites.com/~snyder/motor.jpg
Are those pulleys on a common shaft? Please describe further... rad1 and rad2 are on a common shaft
The most frustrating problem is joining the wire together. I bought some tiny stainless steel tubing from Ebay. The idea is to use this as a sleeve and solder/braze it together. It hasn't arrived yet. I have been unable to find small high pressure crimp fittings.
Be careful. Your joint may wind up a lot stronger than the wire. It needs to be only *as* strong. Will the heat change the metallurgy to the point of weakening? Yes. Annealing after welding/soldering will help. If the alloy is changed

significantly, anything is possible

The second problem is the wire slipping on the pulleys.
Try a small 'V' shaped groove lathe cut into the pulley face. The wire should ride in the groove on it's two sides. That will double the contact area. I call it Twin Tangental Touching (TTT), mainly 'cause I couldn't resist the alliteration.

I will send anyone coming up with a solution to either of these problems a piece of wire to play with, assuming it is something I can use. Wire description at: http://www.pacificsites.com/~snyder/Ebay/Flexinol%20Test%20Data.htm This wire has a transition temp ~100C. This helps resolving the cooling side. The heating side can be easily insulated with cheap materials(styrofoam). I am hoping to put this on a bicycle and operate with solar power. Any comment/suggestions are welcome. Thanks in advance. Larry

mike
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http://improve-usenet.org/ I appreciate your input. Please send me a mailing address and I will send

wire monday. Larry

"m II" wrote in message

Larry Snyder wrote:
rad1 and rad2 are on a common shaft
You will have to refresh my memory on the workings of the wire.
If the piece f2 between the two rad3s contracts, then won't the opposite direction wraps on rad1 and rad2 be fighting each other? Yes. The different forces from heat will determine diection of rotation.
The last time I looked into nitinol wire, I somehow got the impression that an eccentric crank setup would be better. The nitinol wire replacing the connecting rod on the crank. Think of your arm muscles lifting the forearm. The nitinol would basically replace the muscle. It could be heated by an electric current.
High torque, very slow speed. Yes. Originally intended this:

http://www.pacificsites.com/~snyder/Motor/high_efficiency_power_conversion.htm Thermal transfer speed is a problem. This new approach fixes that.
Larry

mike
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Larry Snyder wrote:

High torque, very slow speed.

Yes. Originally intended this:
http://www.pacificsites.com/~snyder/Motor/high_efficiency_power_conversion.htm Thermal transfer speed is a problem. This new approach fixes that.
I note that there were a bunch of wires in parallel in one of the setups. Later, there is a mention of 1 hp per pound of wire. I can see the need for increasing metal density, so paralleling is good.
The new setup has one wire. That is basically using the mass of metal in a series fashion, rather than parallel. This should give a speed increase at the expense of torque .
If power output is torque times speed, what ratios are you looking at between the parallel and serial connections?

mike

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