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Joolz
Starting Member
7 Posts |
 Posted - 12/10/2009 : 5:49:45 PM
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Hi all forgive me if this info is elsewhere but I can't find it.
Can someone please explain where the magnet to trigger the reed switch should be placed in order to get the timing right. I'm presuming if you have more than 4 magnets on the rotor this will require different timings ?
Also on some of the origonal newman designs he has the commutator triggering more than once per revolution whereas most designs here only trigger once per rev.
Also one coil or two ? Daftman's designs have two whereas other designs have just one surrounding the rotor. Can someone explain the differences ?
Thanks for any replies
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comwarrior
Moderator
United Kingdom
477 Posts |
Posted - 13/10/2009 : 1:09:19 PM
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hi joolz,
I'm not an expert on newman motors, but this one i can answer...
Magnets on your rotor must be simetrical and all north pointing out.
Simetrical as in if your using 2 then they are opposite each other...
if using 4 then their at 90 deg to each other... etc etc...
One coil or two? that depends...
If your using a reed switch then you only need one...
If you don't use a reed switch then you'll need two...
Hopefully, thats answerd your questions...
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Generator Systems Moderator
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http://www.youtube.com/user/comwarrior69 |
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Trait
New Member
USA
39 Posts |
Posted - 14/10/2009 : 5:29:08 PM
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Hey Joolz,
The last mini Newman I built had a double pole rotor meaning a North and south pole, and ran off a reed switch on a commutator.
You see, the Newman motor has two drive coils hooked in series, one a north coil and one a south coil essentially...
Trigger your rotor either 10-15 Degrees past the center of the coil or 30 % before the center of the coil. (This depends on if you want to use attraction or repulsion.
I think if you wanted to use a 4 pole rotor I'd use attraction for max torque because you'd be pushing away from the previous magnet and pulling the other in for 20 degrees or so. (For a 4 pole rotor, I'd use alternating magnet poles, N, 90 degrees later South, 90 Degrees later North, 90 degrees later South again.) A monopole Newman would be limited to a very short drive range, but I can see running one with a pulse to the drive coils just after the rotor passed the drive coils. Of course you'd have to run the coils in parallel.
One important thing to remember is to cut off the the power to your coils before your coil slows down your rotor. You want to keep the momentum going. (For instance, in an attraction rotor, cut off the pulse 10% before Top dead center of the coil. )
Hope all this helps!
Don't mean to go against what you said Comwarrior, I'm just stating how I've built in the past.
Take care guys! |
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Newman Motor basics
