Making a Solenoid ??

I was looking for a solenoid 1.5 years ago (for fuel shutoff on my 26 years old Onan diesel generator), and I learned then that there is a great multitude of solenoids available, and that companies could custom make them also. I would look into buying them, at your quantity.

To get a magnetic B-field of 1 Tesla over an airgap of 1mm, about 1000 Ampere-turns is needed. Proportional to the airgap. The magnetic force is ~50 N/cm2 if you have one Tesla, it goes as B-squared. Iron saturates at ~ 2 Tesla. Have the coil as close to the airgap as possible, because magnetic flux wants to leak.

Find a pinball machine seller/servicer/owner/operator, and look at drop target reset solenoids. I once had a pie-in-the-sky dream about mounting

(I used to repair pinballs, video games, jukeboxes, and so on. It was a pretty neat job - after work, we could all go into the showroom and play the games for free. :-) During my interview, I said, "I'm gonna be honest - I like video games, and after one's fixed, it has to be tested, right? :-)" )

Good Luck! Rich

Why do you need 8 Oz of force over 3/8 inch travel to operate the pallets of a reed organ? It sounds like you are trying to depress the keys directly rather than the internal valves. You'll find that you have specified a robust solenoid that will "eat" lots of power. The force equation for a magnet in terms of the amp-turns required is: NI = lg(2*F/(uo*Ae))^1/2. Where NI = amp turns, lg = length of the air gap in meters, F is the required force in newtons, uo is permeability of space, 4*Pi*10^-7, and Ae is the pole area in meters squared. I'll leave it up to you to figure out how many amp-turns you need. It's a lot.

You might be better off purchasing direct pipe organ valve magnets which can sometimes be had for a dollar or two apiece, used. These things have a built on pallet and look like a relay. They open about 1/8 of an inch or so to uncover a hole letting air out to sound a pipe. Typically they run on 12 volts and have a resistance of 60 ohms or so. It shouldn't be hard to adapt them to operate a reed organ. Check ebay under pipe organs, there's pages of organ parts and junk. E-mail me directly if you want more information, I've done lots of work with organs and have midi-ized a pipe organ and am working on another. montassocatyahoodotcom. Bob

Thanks much, Bob. But the formula is beyond me. I will contact you off list.

Thanks again.

Bill And thanks to everyone else who has offered suggestions and help!!

I built this organ back in '89 - '91 and it is all MIDI. If you need sime 8051 source code and schematics, let me know.

GG