ES DIY Motor Challenge

Electric Motors and Controllers
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Farfle   1 MW

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Re: ES DIY Motor Challenge

Post by Farfle » Nov 10 2012 11:54am

pkirkll wrote:Maybe we could get one kudo just for entering??????
:D
At least one kudo for entering a legit torque number, that takes a bit of dedication to find.
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Miles   100 GW

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Re: ES DIY Motor Challenge

Post by Miles » Nov 10 2012 11:56am

Steady on.... We don't want to devalue the kudo... :)

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Farfle   1 MW

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Re: ES DIY Motor Challenge

Post by Farfle » Nov 10 2012 11:57am

Miles wrote:Steady on.... We don't want to devalue the kudo... :)


Lol, no false kudo inflation.
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Re: ES DIY Motor Challenge

Post by pkirkll » Nov 10 2012 12:43pm

:D

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Miles   100 GW

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Re: ES DIY Motor Challenge

Post by Miles » Sep 24 2013 3:43am

Edited the first post to add the new rules.
http://www.endless-sphere.com/forums/vi ... 30&t=14484

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Lebowski   1 GW

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Re: ES DIY Motor Challenge

Post by Lebowski » Sep 24 2013 4:07am

somehow to me the rules don't make sense (sorry :| )

with the specific torque etc, what it boils down to is

Torque should be larger than 0.2 * kg ^2 + 3 * kg

The weight (kg) squared means... well... lets say we have a motor with a certain weight. Taking two of
these and putting them on the same axle means the motor weight doubles and the torque doubles. But,
because of the square term the torque should more than double to be conform the challenge.

My feeling is that if one motor is conform the challenge, two of these motors combined should also
be conform the challenge...?

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Miles   100 GW

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Re: ES DIY Motor Challenge

Post by Miles » Sep 24 2013 4:15am

Let's try with the example I gave.

1.2 kg motor needs to output 3.9 Nm

2.4 kg motor needs to achieve 2.4 * 0.2 + 3 = 3.48 Nm/kg

This requires 3.48 * 2.4 = 8.35 Nm

What's wrong with that?

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Lebowski   1 GW

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Re: ES DIY Motor Challenge

Post by Lebowski » Sep 24 2013 4:21am

Miles wrote:Let's try with the example I gave.

1.2 kg motor needs to output 3.9 Nm

2.4 kg motor needs to achieve 2.4 * 0.2 + 3 = 3.48 Nm/kg

This requires 3.48 * 2.4 = 8.35 Nm

What's wrong with that?
Well, what this means is that a 2.4 kg motor needs to perform better than two 1.2 kg motors, meaning that it is not 'allowed' to put 2 motors on one axle (which doesn't make sense).

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Miles   100 GW

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Re: ES DIY Motor Challenge

Post by Miles » Sep 24 2013 4:27am

Why would you want to do that? Of course, 2 small motors won't perform as well as one big motor.... :)

The whole point of the calculation is to allow for the advantage gained as motor weight increases. This means that you are leveling the field for motors of differing weights, within each weight category.

Of course, you could dispute the level of advantage we've allowed for....

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Miles   100 GW

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Re: ES DIY Motor Challenge

Post by Miles » Sep 24 2013 4:54am

Miles wrote:Of course, you could dispute the level of advantage we've allowed for....
Suppose we changed it to 0.1 * motor weight + 3.2 ?

1.2kg motor needs to output 3.96 Nm

2,4kg motor needs to output 8.25 Nm

Is this more realistic?

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Miles   100 GW

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Re: ES DIY Motor Challenge

Post by Miles » Sep 28 2013 1:40pm

As we also have the three weight classes, now, I think it would be quite sensible to start with a low value for the multiplier.

Any objections to: 3 + 0.1 x motor weight in kg, for the specific torque in Nm/kg ?

Anyway, it's all a bit academic, at the moment.... :mrgreen:

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Lebowski   1 GW

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Re: ES DIY Motor Challenge

Post by Lebowski » Sep 28 2013 2:25pm

Miles wrote:As we also have the three weight classes, now, I think it would be quite sensible to start with a low value for the multiplier.

Any objections to: 3 + 0.1 x motor weight in kg, for the specific torque in Nm/kg ?

Anyway, it's all a bit academic, at the moment.... :mrgreen:
how many peoplle have ever build a motor from scratch ?

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Miles   100 GW

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Re: ES DIY Motor Challenge

Post by Miles » Sep 28 2013 2:27pm

Lebowski wrote:how many peoplle have ever build a motor from scratch ?
You :)

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Re: ES DIY Motor Challenge

Post by Arlo1 » Sep 28 2013 2:55pm

And me
My Leaf motor controller build. http://endless-sphere.com/forums/viewto ... 27#p963227
My YSR build http://www.youtube.com/watch?v=BRo8r5g4NBg
RC and most types of Lithium batteries you MUST know your individual cell voltages charging and discharging.
Don't keep them were you cant afford smoke or fire!
Never above 4.2v never below 2.7v EVER!!!
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http://www.undergroundelectrics.ca/

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Lebowski   1 GW

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Re: ES DIY Motor Challenge

Post by Lebowski » Sep 28 2013 3:32pm

farfle?

I'm now coming up on one year commuting to work with my motor, about 5000 trouble free km's :D

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Arlo1   100 GW

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Re: ES DIY Motor Challenge

Post by Arlo1 » Sep 28 2013 4:21pm

Lol yeah mine was 100% troubble with the iron powder epoxy but a fun project and I will return to it.
My Leaf motor controller build. http://endless-sphere.com/forums/viewto ... 27#p963227
My YSR build http://www.youtube.com/watch?v=BRo8r5g4NBg
RC and most types of Lithium batteries you MUST know your individual cell voltages charging and discharging.
Don't keep them were you cant afford smoke or fire!
Never above 4.2v never below 2.7v EVER!!!
Support me on Patreon. https://www.patreon.com/user/posts?u=6842045
http://www.undergroundelectrics.ca/

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Farfle   1 MW

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Re: ES DIY Motor Challenge

Post by Farfle » Sep 29 2013 1:42pm

Sadly I don't think I am eligible, as I only have peak dyno numbers. If I were to hazard a guess, I would say that its good for 160-190 phase amps continuous which would leave me at 58-69nm. it weighs 15Kg, so if my WAG continuous numbers are close, I am at 3.8-4.6 Nm/Kg. No idea where that puts me at the current contest rules.
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Miles   100 GW

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Re: ES DIY Motor Challenge

Post by Miles » Sep 29 2013 3:09pm

Using 3 + 0.1 * motor wt. you'd need to be able to sustain 4.5 Nm/kg continuously.

Using 3 + 0.2 * motor wt. you'd need to be able to sustain 6 Nm/kg continuously.

Considering that your motor is far from being optimised for weight ...............

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Farfle   1 MW

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Re: ES DIY Motor Challenge

Post by Farfle » Sep 29 2013 4:33pm

Miles wrote:Using 3 + 0.1 * motor wt. you'd need to be able to sustain 4.5 Nm/kg continuously.

Using 3 + 0.2 * motor wt. you'd need to be able to sustain 6 Nm/kg continuously.

Considering that your motor is far from being optimised for weight ...............

Awesome, it doesn't look half bad. I could probably shave 2-3kg off of it without too much work, but on top of all of the structural modifications, Its copper/iron ratio is not set up for maximum continuous power, more towards burst power without saturating.
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Miles   100 GW

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Re: ES DIY Motor Challenge

Post by Miles » Sep 29 2013 4:40pm

So, shall we start off with the 0.1 multiplier, then? :)

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Farfle   1 MW

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Re: ES DIY Motor Challenge

Post by Farfle » Sep 29 2013 4:46pm

Miles wrote:So, shall we start off with the 0.1 multiplier, then? :)
.1 is pretty achievable for a novice with some preparation, but if we are shooting for something special, then .2 should be the metric.

(It also gives me something to shoot for with the next motor :mrgreen: )
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Miles   100 GW

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Re: ES DIY Motor Challenge

Post by Miles » Sep 29 2013 4:56pm

It's the base number that we'll be increasing to "raise the bar". The weight multiplier factor will be adjusted to smooth the transition between the weight groups. So, it's more related to addressing the advantage of scale.

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Farfle   1 MW

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Re: ES DIY Motor Challenge

Post by Farfle » Sep 29 2013 5:20pm

Miles wrote:It's the base number that we'll be increasing to "raise the bar". The weight multiplier factor will be adjusted to smooth the transition between the weight groups. So, it's more related to addressing the advantage of scale.

Then I say that .1 is a great place to start :pancake:
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Miles   100 GW

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Re: ES DIY Motor Challenge

Post by Miles » Sep 29 2013 5:30pm

Ok. I'll make the change. No more changes after this..... :)

KarlJ   100 W

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Re: ES DIY Motor Challenge

Post by KarlJ » Mar 20 2014 6:04am

most efficient is going to be an axial flux design......, quite simple to DIY also.

EG use an otherwise destroyed motor as a base neo's on the outside coils on the inside
pick magnets you can get at reasonable money
http://www.fieldlines.com/index.php?act ... 2538;image
pick big wire = power handling without melting
no laminations to saturate = pump in as much power as you can, keep an eye on the temps.

a 5kW wind turbine motor will run 50kWW in short bursts no problems similar RPM's required too match made in heaven.

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