2 speed (could be auto) gearbox

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gwhy!   100 kW

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Re: 2 speed (could be auto) gearbox

Post by gwhy! » Oct 19 2010 5:01pm

mwkeefer wrote:gwhy,

in the post above, is that outrunner attached to just a mount or is that another reduction stage?

Great work, soon we will need valve bodies to control shift points? {kidding}

-Mike

PS: My 4 year old picked out a new book/toy, from Smart Lab called Motor Mania. Supposed to be for 8+ but he pointed out the pinion gear, the spur gear and idler and a few other bits properly... nearly all of em so I figured if he knows what they are and understands them why not. I only mention becuase once we built the first thing, he tried to make a friction drive for his 12" spiderman bike - best part, it worked if he wasn't on it (tiny little motor) it moved anyway...
No the outrunner is just mounted to a plate ( no reduction ) total reduction as it is is 5.5:1 low and 2.75:1 high.

Kids are great and its surprising how much they do pickup :D

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gwhy!   100 kW

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Re: 2 speed (could be auto) gearbox

Post by gwhy! » Oct 27 2010 3:05pm

Update:
I have spun the GB up ( sorry no vid yet ) it works, and its quite and minimum additional current drain which I am very pleased about, But I have got a problem :cry: with reversing the controller direction. Before I made this GB I messed about with the reverse option on a 6fet sensored controller and it worked very well but I have done the same thing on a 12fet and It do work but the timing is so far out in reverse its not usable ( I sure it was nowhere near as bad when I was playing before with the 6fet ) . I know Jeremy uses the reverse option with his internal mounted hall rc motors and im wondering if there the timing worked out with his setup ( Please Jeremy if you read this please can you comment )

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Jeremy Harris   10 GW

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Re: 2 speed (could be auto) gearbox

Post by Jeremy Harris » Oct 27 2010 3:23pm

You're right, I'm running the same speed forward and reverse on modded 6 FET controllers. I programme the speeds to 100% (the software won't let you get over 100% for reverse) and have the motors zero timed. My Halls are internally mounted at 120 deg, in the stator slots, and the windings are connected in star (wye). The timing is exactly neutral in this configuration I've found.

Jeremy
Please ask questions on the forum, rather than by PM, as it helps others and you'll get a better range of answers.

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gwhy!   100 kW

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Re: 2 speed (could be auto) gearbox

Post by gwhy! » Oct 27 2010 3:41pm

Thanks Jeremy,
Ok I will need to investigate, I am using one of my old hall sensor mounts that wasn't quite at the correct spacing so this may be the problem.

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Jeremy Harris   10 GW

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Re: 2 speed (could be auto) gearbox

Post by Jeremy Harris » Oct 27 2010 4:07pm

Here's a 'scope shot of one of my modded motors that shows the neutral timing:

http://endless-sphere.com/forums/downlo ... p?id=47799

I haven't tried any different timings, but would expect to see significant rpm and torque variation between the two directions with anything other than neutral timing.

Jeremy
Please ask questions on the forum, rather than by PM, as it helps others and you'll get a better range of answers.

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gwhy!   100 kW

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Re: 2 speed (could be auto) gearbox

Post by gwhy! » Oct 29 2010 4:36pm

I setup a new set of hall sensors for neutral timing ( checked on a scope ) but still no joy Im wondering if its something to do with the 17.1 degree spacing that im using. I need to think about this some more :? .

Edit: I think when I tried it before it was with 60 degree spacing ( which worked ) ... but cant get my head round why it should make a difference yet.

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Thud   100 MW

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Re: 2 speed (could be auto) gearbox

Post by Thud » Oct 29 2010 5:14pm

I suspect your having issue with the halls in the delta termination on the dlrk wind.
here is a potential problem if your going to revers a motor.
study the diagram below.

the green arrows are at true 120deg. spacing between the phases. Assume the top green arrow is centerd on a North pole.
all of the blue arrows are on the 6 remaining North magnetic poles.

Using your 17.14 degree spacing will allow the moto to come into time between any 2 stator teeth (once a hall sequence is identified for the direction of spin desired) This leaves you with a dramatic diferance in the timing if you attemp to revers the motor.

A possible senario for a fix it to make certain you are landing between stator phase sections. If i am thinking correctly this will be as close to a true nuetral as you are going to get. This means the center Hall on any of the green arrows. from 14 positions that work in one direction to 6 that are neutral.

Image

I may completely wrong.....(just ask my wife :lol: )
geometricly speaking, its a far simpler world with a poll count that allows ABC winding senario's
hope this helps.
get some......

All information & advice provided by Thud are "Open Source" & free for personal use & distribution under the following agreement linked below.
http://creativecommons.org/licenses/by-nc-nd/3.0/

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gwhy!   100 kW

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Re: 2 speed (could be auto) gearbox

Post by gwhy! » Oct 29 2010 6:48pm

Yes it do help and sort of makes sense from the symptoms that I am seeing when reversing the motor. Cheers Thud, the picture really helps. I will try what you suggest and report back.

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gwhy!   100 kW

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Re: 2 speed (could be auto) gearbox

Post by gwhy! » Nov 04 2010 3:52pm

Ok small update:
I have not tried the reverse function from the controller yet ( as I need to sort out the larger hall placement ) But have manually tried it under load in both directions pulling 2kw And it was faultless and very quite ( the motor was louder ). This project will now be put on hold until I can find the time to do the hall sensors. I am planning to try to make a dog shift type ( simular to Thuds ) but using gears instead of sprockets. The reversing GB is very good but I really need a GB that will back drive with out being over engineered. I havent got a clue how Im gonna do a dog shift GB yet with only really basic tools but I do like a challange :mrgreen: ..

SHARKBITEATTACK   10 W

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Re: 2 speed (could be auto) gearbox

Post by SHARKBITEATTACK » Sep 30 2019 3:17am

Did anything ever come of this? I've been obsessing about 2 speed gearboxes lately and remember this concept from years ago. I recall there was another member that did this as well but I can't seem to find the thread.
WTB 9C 2810 or 2812 motor

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wineboyrider   100 MW

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Re: 2 speed (could be auto) gearbox

Post by wineboyrider » Sep 30 2019 7:56am

SHARKBITEATTACK wrote:
Sep 30 2019 3:17am
Did anything ever come of this? I've been obsessing about 2 speed gearboxes lately and remember this concept from years ago. I recall there was another member that did this as well but I can't seem to find the thread.
THUD
He had one at the Deathrace.
ES IS SAVED! THANK YOU JUSTIN.

SHARKBITEATTACK   10 W

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Re: 2 speed (could be auto) gearbox

Post by SHARKBITEATTACK » Oct 02 2019 1:21pm

wineboyrider wrote:
Sep 30 2019 7:56am
SHARKBITEATTACK wrote:
Sep 30 2019 3:17am
Did anything ever come of this? I've been obsessing about 2 speed gearboxes lately and remember this concept from years ago. I recall there was another member that did this as well but I can't seem to find the thread.
THUD
He had one at the Deathrace.
Is there a link to a thread?
WTB 9C 2810 or 2812 motor

Diva   100 mW

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Re: 2 speed (could be auto) gearbox

Post by Diva » Oct 02 2019 1:58pm

I've found another option. I wanted a 2 speed gearbox like the RC ones, but with a manual clutch. Aaaand... I've found a scooter company that use exactly what I'm looking for with their ICE engines! It's The Uber Scoot Evo: http://www.evopowerboards.com/models/70X.html
Here is a view of the gearbox: https://scooter.fandom.com/wiki/Evo_two ... n_assembly
And where to get it: https://www.neoscooters.com/search.asp? ... rice=&pg=1

I got one but haven't used it yet. It seems quite robust. It is supposed to be used with a 2 stroke 70cc engine, let's say 'round 5HP but not many torque. My goal is to use it under 1000W peak so it should be bulletproof...

Grantmac   10 kW

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Re: 2 speed (could be auto) gearbox

Post by Grantmac » Oct 02 2019 3:38pm

So are they using a centrifugal clutch to engage the high gear then freewheeling the low?

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Miles   100 GW

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Re: 2 speed (could be auto) gearbox

Post by Miles » Oct 02 2019 5:11pm


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