Help with making a Turnigy Aerodrive SK3 work with halls

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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby gwhy! » Mon Dec 26, 2011 6:47 am

with the older aerodrives sk3 that I have ( which are around the same spec as your one ) The no load current when the halls are setup correctly and the controller is working 100% will be around 2-3A, and on a scooter throu the grearing I gestimate the current no-lopad current should be no more than 3.5A ( this is what it is on my bikes ), the new type motors have a support bearing and these have been known to suck a addition 2A ( in my case anyway ).
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby irv » Mon Dec 26, 2011 6:11 pm

gwhy! wrote:with the older aerodrives sk3 that I have ( which are around the same spec as your one ) The no load current when the halls are setup correctly and the controller is working 100% will be around 2-3A, and on a scooter throu the grearing I gestimate the current no-lopad current should be no more than 3.5A ( this is what it is on my bikes ), the new type motors have a support bearing and these have been known to suck a addition 2A ( in my case anyway ).


Thanks for sharing! Based on your numbers, I think my halls are properly setup testing with no load. It's good to know you were also able to make the SK3s work. Do you have a build thread or website I can check out to learn a thing or two? What kind of controller or ESC are you using? And what kind of gear ratios do you run the motor through just so I can compare notes. On mine it's 16T front, 70T rear sprocket, and 10" tires.


HumboldtRc wrote:Uhh.... 20amps is your problem. That motor can pull 80-100 amps easily. Try it with a 6s 100-150amp car esc and you will feel the toque the motor reply can produce.


I've given this more thought and it's starting to make more sense now. I initially used a 48V 1000W ebike controller but it was sluggish. I was hoping the 72V 1500W ebike controller would improve this. Under no load it did, so the outrunner spun faster. But when riding the scooter, current was still not enough to provide torque to spin the motor under load. So the higher voltage could spin the the motor faster but doesn't improve torque as how higher amps could. OK so I'll start hunting for a higher amp controller, I can probably stick to 48V
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby gwhy! » Mon Dec 26, 2011 7:01 pm

irv wrote:
gwhy! wrote:with the older aerodrives sk3 that I have ( which are around the same spec as your one ) The no load current when the halls are setup correctly and the controller is working 100% will be around 2-3A, and on a scooter throu the grearing I gestimate the current no-lopad current should be no more than 3.5A ( this is what it is on my bikes ), the new type motors have a support bearing and these have been known to suck a addition 2A ( in my case anyway ).


Thanks for sharing! Based on your numbers, I think my halls are properly setup testing with no load. It's good to know you were also able to make the SK3s work. Do you have a build thread or website I can check out to learn a thing or two? What kind of controller or ESC are you using? And what kind of gear ratios do you run the motor through just so I can compare notes. On mine it's 16T front, 70T rear sprocket, and 10" tires.


I dont have any completed build threads as such but here is a couple of my projects.

viewtopic.php?f=28&t=22245&hilit=new+old+build
viewtopic.php?f=12&t=17576
viewtopic.php?f=6&t=25703&p=383738#p383738
viewtopic.php?f=12&t=32042
viewtopic.php?f=28&t=21450&hilit=2+speed+reversing+gearbox

There are a couple of very old youtube vids of my very first e-bikes on my youtube channel




all the info that you need for hall placement is within this thread:
viewtopic.php?f=6&t=25703&p=383738#p383738

a lot of info in this thread about the controller that I use and the sort of problems that may need to be overcome:
viewtopic.php?f=2&t=16910

I have put these small motors ( all fitted with hall sensors ) on bicycles upto full size motorcycles and have used either moddified 6fet controllers or moddified 12fet controllers

all the gearing is based around a road speed of between 20-30mph, I did gear a bicycle ( ready to ride weight of around 22kg ) for 40mph just to test and it worked well for road use, using a 6fet controller.
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby irv » Mon Jan 02, 2012 12:21 pm

@gwhy!, I checked out the links you posted and watched the videos too. Very cool and inspiring. Great job on all the gearing and the very polished custom work too.

I'm curious about the controllers, you mentioned they are just 6 and 12 fet controllers but you get 80A or something out of them. What kind of controllers are they and how much were they? Were they setup to deliver that or did you have to modify them heavily? And how difficult is it to modify? My soldering skills is only good until connectors and hall sensors, is it a big step to modifying controllers? My controllers include a a ConhisMotor and a HuaTong.

I saw the thread about the controllers cutting out. So far I have only encountered the LVC problem in the past, but I'll keep the thread in mind for future reference once I get the amps up.

Also I've been looking for controllers online and I found a number of options, wondering if anyone stumbling on this thread has any recommendations:
- Lyen Controllers: Tried and tested here on endless spehre, but currently outside my budget.
- Kelly Controllers: Too pricey for my budget.
- Greentime Controller: Saw a couple of threads about this and it looks like the best bang for the buck. Seems like a few members have been using this too.
- GoldenMotor Controller: BAC-0282P, 48V/50A, $65. Cheaper than Lyen's, seems a bit under spec but it is programmable, wondering if anyone has been able to push it.
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby gwhy! » Mon Jan 02, 2012 5:35 pm

irv wrote:@gwhy!, I checked out the links you posted and watched the videos too. Very cool and inspiring. Great job on all the gearing and the very polished custom work too.

I'm curious about the controllers, you mentioned they are just 6 and 12 fet controllers but you get 80A or something out of them. What kind of controllers are they and how much were they? Were they setup to deliver that or did you have to modify them heavily? And how difficult is it to modify? My soldering skills is only good until connectors and hall sensors, is it a big step to modifying controllers? My controllers include a a ConhisMotor and a HuaTong.

I saw the thread about the controllers cutting out. So far I have only encountered the LVC problem in the past, but I'll keep the thread in mind for future reference once I get the amps up.



Thanks for the kind words. the controllers are the same controllers that Lyen sells but his are modded by him, mine were box standard controllers when I bought them then modded by me. Lyen sells his modified controllers for a very fair price ( PM him and ask how much for a modded 6fet or modded 12fet fitted with 3077 fets will be ) go with a 12fet if you can stretch to it.
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby nieles » Fri Jan 06, 2012 3:05 am

irv,

the problem is, even with your 70/16 gearing you are geared for a topspeed of ~70km/h (no-load speed) this gearing is way too tall
is it possible to go with a 13t sprocket? this will lower your gearing to ~55km/h (no-load)

calculations:
Spur Tooth Count: 70
Pinion Tooth Count: 16
Total Voltage: 42.00
Motor KV: 149
Tire Diameter (inches): 10
Spur/Pinion Ratio: 4.38 : 1
Tire Circumference (inches): 31.42 inches (797.96 mm)
Rollout: 7.18:1
Total Motor Speed: 6258 RPM
Vehicle Speed: 42.55 mph (68.36 km/h)
http://www.scriptasylum.com/rc_speed/top_speed.html

if you want to do some calculations yourself, put the first 3 ratios on "1"
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby irv » Mon Jan 09, 2012 11:17 am

nieles wrote:the problem is, even with your 70/16 gearing you are geared for a topspeed of ~70km/h (no-load speed) this gearing is way too tall
is it possible to go with a 13t sprocket? this will lower your gearing to ~55km/h (no-load)


Thanks for the feedback on gearing! I don't mind the top speed you pointed out if only the motor can get there under the current setup, but I agree that looks too tall. Based on your recommendation, I'm looking into an 11T and a 13T currently from http://www.electricscooterparts.com/sprockets.html. Hopefully either of these would work better.

Thanks for sharing the link to the calculator as well, this is very helpful. I'm wondering though, is there any way to read the data to check whether or not a setup is too tall for a motor? For example is there a way to compare "Calculated Axle Torque" with what's needed for my loaded EV to accelerate (maybe there's a calculation that would take into account EV + Rider Weight).
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby nieles » Mon Jan 09, 2012 3:39 pm

if you have acces to a lathe, or know someone who does. you can buy the sprokets way cheaper here:
http://www.surpluscenter.com/sort.asp?c ... yword=PH25

you can just buy the sprockets with the smallest bore and machine it to the size hole you need (8 or 10mm i think?)

i dont know a online calculator that can calculate the stuff you want to do. if you find one, please post it.

well there is this one:
http://ebikes.ca/simulator/

but it is only for motor setups they tested. so not really helpful in this situation.

you "could" make a excell spreadsheet with the neccesary formulas, and make a calculator yourself (for gearing this is easy). but this wont be easy.
to give you an idea what is needed:

first you need to calculate the power needed to accelerate at a certain rate and overcome the winddrag. (some formulas here: http://craig.backfire.ca/pages/autos/drag)
this is the power needed.

then you need to calculate what power you are producing:
power= torque*speed

formula for torque from the motor. torque= Kt( torque constant of the motor)*Phase amps
Kt (N-m/amp) = 9.5478 / Kv

in theory: phase amps= battery amps* (1/(Dutycycle/100)) where the dutycycle is 0-100% "throttle"

the chinese controllers like the lyen controller will limit the phase current to a preprogrammed value. so this alse needs to be taken in to account. (the controller will again calculate the phasecurrent form battery current with the above formula, as these controllers dont have the hardware to measure phase currents)

also the BEMF voltage form the motor will limit the max phase currents. at a higher speed the BEMF voltage will be higher. but i have no idea on how to calculate this.

**NOTE: there might missing some important steps in the above calculations.**
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby irv » Mon Jan 09, 2012 7:43 pm

nieles wrote:if you have access to a lathe, or know someone who does. you can buy the sprokets way cheaper here:
http://www.surpluscenter.com/sort.asp?c ... yword=PH25

you can just buy the sprockets with the smallest bore and machine it to the size hole you need (8 or 10mm i think?)


Thanks for the link, those sprockets are way cheaper! I don't have access to a lathe but I was able to buy a drill press on craigslist for some change. I'm guessing that could work if I can center the sprocket being drilled and keep it in place. I only need 8mm, so 5/16 bore should work. At this price I can try different-sized sprockets :)

The simulator is pretty interesting. It doesn't seem like there's a straightforward equation that I can use for my motor, but maybe the data points from this can help with making estimates.
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby dontsendbubbamail » Tue Jan 10, 2012 8:24 am

irv wrote:
nieles wrote:if you have access to a lathe, or know someone who does. you can buy the sprokets way cheaper here:
http://www.surpluscenter.com/sort.asp?c ... yword=PH25

you can just buy the sprockets with the smallest bore and machine it to the size hole you need (8 or 10mm i think?)


Thanks for the link, those sprockets are way cheaper! I don't have access to a lathe but I was able to buy a drill press on craigslist for some change. I'm guessing that could work if I can center the sprocket being drilled and keep it in place. I only need 8mm, so 5/16 bore should work. At this price I can try different-sized sprockets :)

The simulator is pretty interesting. It doesn't seem like there's a straightforward equation that I can use for my motor, but maybe the data points from this can help with making estimates.



irv,

If you are going to use a drill press, don't buy a 5/16" sprocket and try to drill it out to 8mm. Buy the smallest bore size you can get because the more metal the drill bit has to bite into the easier it is to keep it on center.

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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby kfong » Tue Jan 10, 2012 10:14 am

A pre-existing hole will self center on a drill press. You just need to keep the part flat to the table and allow the drill to move the part to center without the part rotating. Vice grips will help, vblocks and a vice is better. Set rotation to slow and don't rush the process.
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby irv » Wed Jan 11, 2012 9:14 am

Thanks for the tips about buying the sprockets with the smaller bores and about using the drill press! I'm new to this so this is really helpful.
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby irv » Thu Jan 26, 2012 4:38 am

I just wanted to share a quick update just in case anyone else stumbles into this thread.

I now have an 11T and a 13T sprocket with an 8mm bore. I plan to try them out this weekend and see if they'll work with the 20A controller.
I was also able to get an 80A brushless controller but I still need to customize the connections and figure out what each is for. I'm excited to try it out... I hope I don't burn my motor in the process.
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby irv » Fri Feb 17, 2012 7:01 pm

I finally tried the 80A controller but, disappointingly, it didn't work.

I tested each hall sensor using a voltmeter and all three are good. The voltage reading changed from 0-5V when I turned the motor by hand.

I tried all 36 phase and hall wire combinations but none of the combinations turned the motor. The amp meter shows current kicking in, with the needle going past 50A max reading if I opened the throttle wide. But the motor just jolts and locks and doesn't really spin. Any ideas on what else I should try?

Here's a bit more info on the controller:
Image

Image

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