Muller Dynamo

[e2matrix]

Guys. I can be some help here. It is easy and less expensive than you think to drive an R/C airplane motor or any other three phase motor of that type. You may have to deal with China if you want the best prices. If you check a site like HobbyCity you can find hudreds of motors, and speed controls. Yes, they are three phase and require the speed control. Normally the speed control needs to plug into a receiver for drive control, but you can buy what is called a servo tester for less than $10 and drive the speed control right from that. I have an 80 amp speed control that I only paid $17 for but you can buy something like 20 amp controls for again $10. I'd be surprised if you if you couldnt find a complete setupf for $40-50. Wait. maybe that's to expensive. If you want to see how the setup works without being in an airlplane you can see it on this video. http://www.youtube.com/user/DadHav#p/u/1/e0q8DDtjvMY
Hope this might help
John H (DadHav)

John,  thanks for that info and link.  Can you provide links to any other favorite motor sources or do you think HobbyCity is best?  Do you have links to something like that $10 servo tester and maybe the 20 amp speed controller for around $10?  Thanks again for your help here!

[i_ron]

Sorry Star. Your post must have went up while I was writing mine. I wouldn't have barged in if I saw yours first. Nice of you to help out if people are interested. You might have to take a close look at the KV rating of the motor right? It looked like Rom's motor wasn't running real high RPM's. Does anyone know about what range the target would be?
John

John

With just the one double coil set I only get 380 RPM. Pulse a bit wide at this time but I doubt it was much over 1000 RPM. I would think acrylic is only safe up to 1500 RPM?  if that...3000 and up is in the realm of orbiting magnets.

I run 280mm rotors at 2000 RPM but that is with the Delrin firmly bolted to a steel back plate.

Ron

[starcruiser]

@DadHav,

No problem. You are right, there are several sources for the less expensive motors and ESC's, the Current rating of the motor and ESC needs to be considered as well as the KV rating. The KV rating is the RPM per volt and the motors are rated to a max voltage and have a max current draw rating, the max current draw is what you want to size the ESC on as well as the rated voltage the motor should run on. The ESC's us MOSFET's in them to switch the legs on the brushless motors and the motors use NEO magnets for the rotor and are either in-runner or out-runner types. The out runner types are where the motor can turns, the top of the motor is where you mount it from. Basically the in runner vs out runner is how the magnets are mounted.

The ones I play with (helicopters ) are out runners and run about 35000 RPM at WOT (wide open throttle). I also have a servo tester and seen them from $15 and up.

You can get low KV rating motors that run on 3.7volts and up, the bigger low KV motors are usually for large high torque applications but these use higher voltages too. you will want a motor that is around 1000 kv and is rated for 1s or 2s LiPo packs (3.7 to 7.4v) these motors can draw several amps too.

[neptune]

@Dbowling . I understand exactly what you are saying However I can only give you the best info I have . The run-out-of-magnets bit came from the horses mouth .
@ Woopy . Brilliant bobbins . where did you buy your cores please?

[woopy]

hi chris

i would recomand to use as much as possible  ( better sayd only ) all bolts and screws and axel   - . in plastic  or INOX = Stainless steel ,  to avoid magnetic interaction with the rotor.

good luck at all

Laurent