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Old Mar 21, 2013, 06:12 PM
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Jack
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I'll reply over on the other post in the more approriate location, I suggest you edit your post and replace it with a notice here to the effect that the conversation can be continued over there.

Then move your post and photos to the other post...

Jack
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Old Apr 11, 2013, 02:16 AM
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Hey i got little side question plz can some 1 give me help/hint on WHAT MOTORS THIS GUY MIGHT OF USED FOR THIS? im sure he is using similar 3 axis gimbal cheep like alex mos and i want to know what motors he used i know the rewining part will be needed for it. but what motors?
this is the video im refering to
MōVI in Action (Quick Video) (0 min 24 sec)
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Old Apr 11, 2013, 03:19 AM
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what about asking that guy directly ?
http://vimeo.com/laforet
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Old Apr 11, 2013, 02:19 PM
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gimbal

I did NO answer.
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Old May 06, 2013, 05:21 AM
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How can I modify the motor(450 heli motor, 11.1v, 3cell) so that it can handle 22.2v(6cell)?
Do I need to length the winding cable only?
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Old May 06, 2013, 05:54 AM
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The motor would have to have windings that are large enough to handle the current the load is drawing.

Do you have a link to the motor for the specs?

Do you know the load you want to put on it (the prop or whatever)?

Jack
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Old May 06, 2013, 06:37 AM
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Quote:
Originally Posted by Tomf35 View Post
How can I modify the motor(450 heli motor, 11.1v, 3cell) so that it can handle 22.2v(6cell)?
Do I need to length the winding cable only?

Well in principle (assuming you're using it in an application that still has a gearbox) leave the windings alone and just double the gear ratio. The motor will have the same current limit and will just rev faster. This also assumes the motor can take the revs without bursting, of course.

PDR
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Old May 06, 2013, 08:01 PM
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It is the stock motor(450mx, 3400KV) that comes with Trex 450 Pro, flybarless.
I have already bought new 22.2v motor for 450, currently using it and want to make stock motor to be spare for 22.2v.
They both looks same in size, stock accept 11.1v and new motor accept 22.2v, what is the difference inside?
How manufacture can make same size motor but different input voltage?
What is the factor changing the input voltage?

FYI, I do have few spare 11.1v motor, no problem even the motor is busted.
I do know about Step-UP or Down transformer. Change pri/sec winding ratio, chages output voltage..
Thanks for the reply but donot want to use gearbox and not applicable.
Load is Trex 450 heli(for Jack)
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Old May 06, 2013, 08:23 PM
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It that this motor?

http://www.amainhobbies.com/product_...s-Motor-3400kV

It is rated for 14.8V (3S charged voltage) and is a 83 gram motor rated for 500W (continuous assumed) and 750W peak for 5 seconds.

Do you have a link to the new motor? With better details and specs for the new motor?

If your new motor is rated for more power it likely a heavier motor and may have larger wire in the windings and be of a higher quality. Did you have to change the rotor gearing for the new motor?

There is no way to double the input voltage on a motor and not also increase the heat if you put the same load on it. If you could rewind it with larger wire to handle the higher voltage, and still keep it at the same Kv, you might be able to do it but it is not likely that there is room in the motor for more strands of wire or larger wire.

So I'm not optimistic at all that you can plan on using the 450MX motor at the higher voltage.

Jack
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Old May 06, 2013, 09:54 PM
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Yes.

New motor : Brand : Rete, Model : HD2223, 6S, 1880KV.
http://www.ebay.de/itm/180876660978?...orig_cvip=true

No gearing change due to reduce in KV.

Without winding modification, it is impossible to use stock motor at 22.2v.
And I ready for modifying, totally remove winding wire and rewind new wire.
I think, we need to double the winding wire length but reduce the wire guage by half, is this correct?

People are moving to 6 cell in 450 size.
And Scorpion has 3 cell and 6 cell lipo motor.
And it is identical in size and weight is more/less the same.
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Old May 07, 2013, 07:42 AM
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Changing the Kv from 3400 to 1880 would be a 55% reduction in potential RPM but if the new motor work, it works. I don't know helo power systems at all or fly helos either.

It is the turns that determines the Kv. If the 3400 Kv was four turns and doubling the length and doubling the turn count to 8 turns would give you a 1700 Kv.

Doubling the length also doubles the resistance in the wire, and if you have to use smaller wire to get the 8 turns to fit, that also raises the resistance in the windings. The current goes up and things get hotter...

But if it has been done and is known to work, and you can do the same things that others have done safely, it should be OK.

Helo power systems are quite different from airplanes...

Jack
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Old May 07, 2013, 05:34 PM
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Thanks Jack
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Old May 09, 2013, 09:45 AM
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Quote:
Originally Posted by jackerbes View Post
Changing the Kv from 3400 to 1880 would be a 55% reduction in potential RPM but if the new motor work, it works. I don't know helo power systems at all or fly helos either.

It is the turns that determines the Kv. If the 3400 Kv was four turns and doubling the length and doubling the turn count to 8 turns would give you a 1700 Kv.

Doubling the length also doubles the resistance in the wire, and if you have to use smaller wire to get the 8 turns to fit, that also raises the resistance in the windings. The current goes up and things get hotter...

But if it has been done and is known to work, and you can do the same things that others have done safely, it should be OK.

Helo power systems are quite different from airplanes...

Jack
Good post!

That motor simply wont work with 6s as is. It actually needs to be rewound or replaced. I have built quite a few and test new designs for Scorpion in 6 and 12s 450's. The wire dia isn't as much of the issue as the 6s motor draws less amps. Although running thicker pure high quality copper windings will be more efficient. But the length of wire is. The type of winding tie also dictates where its torque curve will hit. And this depends on what kind of flying you are after, gearing, blade size, and battery load. You would be better off just buying an appropriate 6s heli motor unless you know what you are doing.
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Old May 09, 2013, 05:38 PM
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Erm - electric motors have a flat torque "curve". Torque varies with amps, but not with RPM.

PDR
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Old May 09, 2013, 06:13 PM
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Quote:
Originally Posted by Peter D Rieden View Post
Erm - electric motors have a flat torque "curve". Torque varies with amps, but not with RPM.

PDR
That is probably true but I can't help but feel there is something in the electromagnetic gearing effect with brushless outrunners that sort of passes for a torque like effect or something like that?

When the magnets are dispersed around a larger diameter and pushing and pulling on arms and hammer heads that are located around a larger diameter, is that not something like having a longer lever? And by a layman's seat of the pants impressions and standards, isn't torque and leverage somewhat similar?

Jack
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