Help with making a Turnigy Aerodrive SK3 work with halls

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Help with making a Turnigy Aerodrive SK3 work with halls

Postby irv » Thu Dec 22, 2011 10:12 am

Inspired by the RC builds here, I got a TURNIGY AERODRIVE SK3 – 6374-149KV outrunner from HobbyKing for my BladeZ electric stand-up scooter. I installed internal halls and went through all 36 combinations for the hall and phase wires. However I can't find a really low current draw when testing, the lowest I got was over 11A under no load (which compared to what I read here seems really high). I got the motor to turn smoothly when there is no load, but when I ride on the scooter it doesn't turn anymore (or turns really slowly when I do a running start). Here are additional details about the build, wondering if anyone can spot if there's something wrong with my setup:

batteries: 48V Turnigy lipos, 15C
controller: 48V conhis motor controller rated for 1kW (I also have a 72V huatong but haven't wired that yet for the scooter)
motor: Turnigy Aerodrive SK3, rated for 12S, 149KV, 2kW+. I think it has 14 magnets, 12 "gaps" on the windings.
halls: SS413A, installed internally, 120 degrees apart
rider: 147lbs

My hypothesis is that the halls may be shot, I had to cram them in really tight spaces. But I wouldn't know if the symptoms above (high no-load current, wouldn't turn when I'm riding on it) support this. And if so, what would be my options? Would going with external halls solve this? Or is it the controller that's the constraint? Thanks for any help!
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby gwhy! » Thu Dec 22, 2011 10:28 am

irv wrote:Inspired by the RC builds here, I got a TURNIGY AERODRIVE SK3 – 6374-149KV outrunner from HobbyKing for my BladeZ electric stand-up scooter. I installed internal halls and went through all 36 combinations for the hall and phase wires. However I can't find a really low current draw when testing, the lowest I got was over 11A under no load (which compared to what I read here seems really high). I got the motor to turn smoothly when there is no load, but when I ride on the scooter it doesn't turn anymore (or turns really slowly when I do a running start). Here are additional details about the build, wondering if anyone can spot if there's something wrong with my setup:

batteries: 48V Turnigy lipos, 15C
controller: 48V conhis motor controller rated for 1kW (I also have a 72V huatong but haven't wired that yet for the scooter)
motor: Turnigy Aerodrive SK3, rated for 12S, 149KV, 2kW+. I think it has 14 magnets, 12 "gaps" on the windings.
halls: SS413A, installed internally, 120 degrees apart
rider: 147lbs

My hypothesis is that the halls may be shot, I had to cram them in really tight spaces. But I wouldn't know if the symptoms above (high no-load current, wouldn't turn when I'm riding on it) support this. And if so, what would be my options? Would going with external halls solve this? Or is it the controller that's the constraint? Thanks for any help!


Have you got a link to the motor ( im guessing this is the new type of motor ) , I have always mounted the halls external and have very good results. Do the controllers run sensorless? the reason I ask this I have a ( sensorless/sensor)controller that conflicts if I connect the halls up and this do draw way to many no-load amps, I normally use keywin/e-crazyman controllers and never had any problems with these.
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby Bluefang » Thu Dec 22, 2011 11:09 am

To me that sounds like either you have the halls in the wrong order or one is shot. You can test the halls by using a volt meter set to read ~5V between the sensor wires from each hall and ground. As you turn the motor it should change on the volt meter, the values dont matter as long as all the halls react the same.

Most likely your halls and phases dont match up properly. Try just swapping 1 pair of phases and 1 halls, assuming its a motor controller with colored wires try swapping the green and blue pairs. I know you said you have been through the 36 combinations, i have done the same about 5 times with a hub motor at one stage and it was just me not doing the 36 combo properly. Good luck, with others who know alot more then me around on this forum i am sure the problem will be solved shortly.
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby irv » Thu Dec 22, 2011 1:21 pm

Thanks for the replies!
gwhy! wrote:Have you got a link to the motor ( im guessing this is the new type of motor )

Image
Here's a link to the motor I used: http://www.hobbyking.com/hobbyking/stor ... duct=18184
This seemed like the best one for EV use among sub-$100 motors in stock at the time I bought it. It's also a good fit in the BladeZ scooter. On your question about the controller running sensorless, I haven't tried this yet but I don't think it can. In the past there have been times when my electric bike malfunctioned when the hall wires weren't connected properly.

Bluefang wrote:To me that sounds like either you have the halls in the wrong order or one is shot.

I think one hall sensor being shot is a good bet, I'll test it with a voltmeter as you suggested. It was a tight fit inside the motor so it's possible that one of them was damaged during installation or during use.
Image

On the halls and phases matching up, I will also give that a try if the volt meter test result is inconclusive. But I used the spreadsheet made by Knuckles from herehttp://endless-sphere.com/forums/download/file.php?id=11560 so I think I went through all the possible combinations. But of course, I could've mixed it up somewhere.
Image

If it turns out that one of the hall sensors is busted, any suggestions on how to remove it? I have it epoxied with JB Qwik. I have access to basic tools, a soldering iron, and to a dremel, so I'll probably try those approaches in that order.
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby irv » Thu Dec 22, 2011 6:54 pm

Here's a video of the motor spinning. Sounds really noisy, probably the chain and the mic being sensitive. It didn't sound as noisy when I was testing it. But it spins. On this video it was cutting out, most likely because I was hitting LVC already because it was running better the previous night when my batteries were freshly charged.

http://www.youtube.com/watch?v=w9J1SKmG ... ature=plcp
(I can't seem to post/embed it)
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby John in CR » Fri Dec 23, 2011 9:44 am

That spreadsheet should be deleted and forgotten. Trying only 6 combos of halls, or 6 combos of phase will get you a good forward or a good reverse. If not, then something else is wrong with the system. Swap only 2 wires at a time to more easily be systematic and keep the process as simple as possible.

I've been putting some thought into internally mounted halls, and while 3 evenly spaced slots is 120°, I'm not sure just any slots will work. Sure they'll be the same as far as the magnets are concerned, but is that also true for the coils of the stator?
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby Tench » Fri Dec 23, 2011 11:01 am

I think your hall positions are wrong, you have them sapced 120 physical degrees around the rotor when they should be spaced 120 deg in relation to one electrical rpm or cycle, with 14 magnets this motor has 7 electrical cycles per one whole revolution of the rotor. This would equate to the hall spacings being at (360/7=51.42/3=17.14 deg) that is one whole physical rotation divided by 7 (7 pairs of magnets) one electrical rpm, then the remaining number of degrees divided by 3,(3 being a third or 360/120) Repositon the halls at 17.14 deg intervals and it will behave correctly.

Took me awhile to get my head around this, it is easy to misunderstand the meaning of 120 deg spacing for halls.

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

Postby gwhy! » Fri Dec 23, 2011 12:21 pm

Tench wrote:I think your hall positions are wrong, you have them sapced 120 physical degrees around the rotor when they should be spaced 120 deg in relation to one electrical rpm or cycle, with 14 magnets this motor has 7 electrical cycles per one whole revolution of the rotor. This would equate to the hall spacings being at (360/7=51.42/3=17.14 deg) that is one whole physical rotation divided by 7 (7 pairs of magnets) one electrical rpm, then the remaining number of degrees divided by 3,(3 being a third or 360/120) Repositon the halls at 17.14 deg intervals and it will behave correctly.

Took me awhile to get my head around this, it is easy to misunderstand the meaning of 120 deg spacing for halls.

Simon.


You are correct, but 120d m spacing should work, as john have said some slot positions work better than others but its nothing to do with coil relationship ( as such ), when the halls are so close to the coils if a coil is energized this in it self can cause a false trigger for the hall ( it wont hold the hall output but can shift the timing very slightly or cause the controller to think something is wrong ) , if using 17.14 d m then the spacing needs to be more precise and its harder to to get the correct spacing if externally mounting the halls , the best trade off is having the halls external at either 60d m but with the middle hall flipped or 68.5d m with all the halls facing the same way.
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby irv » Fri Dec 23, 2011 1:21 pm

John in CR wrote:That spreadsheet should be deleted and forgotten. Trying only 6 combos of halls, or 6 combos of phase will get you a good forward or a good reverse. If not, then something else is wrong with the system.


You're probably right. I experimented with external halls for a bit and found a working combination within the first 6 tries by just changing the hall wires and keeping the phase wires the same. Although I wasn't able to get the external mounting right but I might revisit that again. On my internal tests where I tried all 36 combos, I wonder if not finding a workable combo in a row hints at a busted hall sensor. Anyway I'll try the volt meter test today.

gwhy! wrote:the best trade off is having the halls external at either 60d m but with the middle hall flipped or 68.5d m with all the halls facing the same way.

Thanks gwhy!, Tench, John in CR, and Bluefang for all the ideas so far. I'll try the externals today too, hopefully I'll have the time so I can finally ride the scooter.
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby irv » Fri Dec 23, 2011 4:53 pm

Lunchbreak update:

I tested the halls using a voltmeter, with the black lead connected to ground, and the red connected to one hall signal wire at a time. At the meter's most sensitive setting (200mV?) and without a battery connection, all register a tiny amount of voltage. So I switched over to the second setting (2000mV?) and connected to the controller/battery. Now two halls registered voltage significantly higher than one hall, which is consistent with the hypothesis that one hall sensor might be shot.

So I cracked the motor open and here's what's inside:
Image
That exposed internal is the positive on that hall sensor (might explain why it registered a tiny voltage without the battery connection, but did not register enough voltage with the battery?).

So I took that out and chiseled the epoxy to prep for a new hall sensor:
Image
Image

I'm done with soldering and about to epoxy the new sensor. Hope it works. If it doesn't I'll shift over to external halls just because it's going to take too much work to stick with internals after this point.
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby irv » Fri Dec 23, 2011 10:11 pm

Updates from this afternoon:

Image

I replaced the busted hall sensor and everything seemed in order with the voltmeter test. So I put everything back together. Without using the spreadsheet for the 36 permutations, I was able to find a wiring combination that worked by just switching the phase wires. But the scooter was still not as responsive as I would've wanted. Plus the wattmeter still showed 10A+ with no load.

So I figured I might as well go through all the combinations so I started switching the hall wires around as well. True enough I was able to find a low current combination, but it was in reverse. But even without looking at the wattmeter initially, I knew this was a better combination because it sounded smoother and seemed to turn faster. This was encouraging so I soldiered on and eventually found an optimal combination. So I guess the spreadsheet can still be useful if the first 6 combos do not provide a no-load low current combination.

Image
http://www.youtube.com/watch?v=HBwHkjwX ... e=youtu.be

I noticed the the motor still got warm, well nothing extreme with just 48v and my low-amp controller, but I might as well put a fan to help with cooling. I salvaged a cooling fan from an old PC and stuck it to the other end of the motor.

Image
Image

Here's a video of the Bladez XTR Comp2 in action. Nothing spectacular at this point. My original over-volted brushed motor had more torque, but top speed is similar based on GPS (25mph). But this is using a 48V 1000W controller, which is just good for 20A. I'll try to use my 72V controller, still just 20A but the higher voltage should add some pep. (BTW, sorry for the poor video, I just propped my smartphone against something).

http://www.youtube.com/watch?v=qsoO4e-d ... e=youtu.be
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby irv » Sun Dec 25, 2011 7:08 pm

I tried using 72V but forgot that the Turnigy watt meter is only good up to 60V... I burned it unfortunately. I've searched here on fixes and saw that Amberwolf was able to do it, but it doesn't seem to be an easy fix. Connecting the hall and phase wires, I realize the color coding don't match up between the Huatong and the Conhis motor controllers.

So I try different combinations, but now only using a Harbor Freight amp meter I bought a while back. It's only rated for 12V, so I wired it in series after the first 3S battery pack. Seems to work but unfortunately, the amp meter doesn't have the same resolution as the Turnigy digital watt meter. I thought I found a good combination that also sounded good enough. But then during testing, I smoked the motor (saw some smoke and it started stalling intermittently). Also noticed that the motor would start smoothly if the throttle was engaged slowly, but that the motor started stalling when the throttle was opened too fast. At first I thought it was the controller tripping because of the amp draw. That might be the case but could it be that my hall and phase combinations aren't optimal hence the high current draw (and the over-heating motor).

So I fanned the motor and tested it quickly. Seems to still be working. Hopefully the magnet wire and the hall sensors are still intact.
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby irv » Mon Dec 26, 2011 12:42 am

OK, tested the halls with the voltmeter and they are still alive. Tested the different hall combinations, found the best one. Motor still works despite overheating earlier today. Motor spins fast when there is no load. But it's pretty slow to accelerate, overheats after a short distance, and never achieves a top speed faster than my over volted brushed motor.

I think I have the internal halls and the controller setup properly, but the weakest link at this point is the gearing. I didn't really plan out the gear ratios yet since I just wanted the motor to work with the halls and the controller. But it seems the motor is designed for high speed and spins nicely when there is no load, but it doesn't do well for torque hence the poor performance and the overheating when I'm riding it.

Image

I first tested using a 16T sprocket on the motor, and a 55T sprocket on the rear that came from a Razor E300. Acceleration was sluggish so I also tested with the larger 70T stock BladeZ sprocket. Still doesn't accelerate like the over volted stock motor. Not sure what gearing options I have though, but will try to look for the smallest front and largest rear sprockets that would fit. Hmmm, maybe that or a motor rewind to get lower KV if gearing doesn't work?
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby HumboldtRc » Mon Dec 26, 2011 1:30 am

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.

Have you seen my mountainboard videos? I'm using the old sk's in the video's, but I'm now using the sk3's but I got the 6364-190kv motor's because they didn't release the sk3 6374 yet when I bought them.
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Re: Help with making a Turnigy Aerodrive SK3 work with halls

Postby irv » Mon Dec 26, 2011 4:19 am

Thanks for the tip... I'm sure the controller's far from ideal, I was trying to build this thing up on a tight budget and I already had the controllers on hand. I figured starting with a low amp controller wouldn't be that bad so I wouldn't burn my motor right away if the current was low enough. When I was using brushed motors, I burnt a few when I over volted and used a high-amp controller.
Image

I was wondering though, wouldn't I overheat the motor faster if I were dumping more amps into it from a stronger controller? I guess the over-heating issue is why I concluded that my current weakest link is probably the gearing. I could imagine that the motor wants to spin fast, but the sprockets are too tall and not allowing it to do so.

But to your point, maybe the weak controller is preventing the motor from spinning under load, so it stalls and there's no back EMF and so even just the 20 amps overheats the motor?

Yes I think I've seen your videos with the jumping and all the fun! Did you use 2 or 4 motors on those? Great to know that you've made good use of the SK3s! Around how much would I have to spend if I went the car ESC + compatible throttle route?
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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.
Image
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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.**
nieles
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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.

Bubba
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