Outrunner Information Thread

[What's_nitro?]

Also, here is a formula some of you might already know:

240/(# of magnetic poles in motor) = Proper hall sensor spacing (in degrees).

I had calculated the spacing for a CC outrunner (14 poles) to be ~17.143 degrees, and after simplifying my work the formula popped out. The spacing for a 4-pole Neu? 60 degrees. A 2-pole Lehner/Novak/LRP/Orion? 120 degrees. An 8-pole Hacker? 30 degrees. The number of stator poles is irrelevant.

[Shonen]

Great find with the simple formula!

What I found from reading the endless-sphere thread was that the sensors work, irrespective of pole count, if they are simply embedded at 120° increments around the stator windings. Every single pole count is taken care of because every single calculated sensor spacing goes into 120° evenly. However, the most common seems to be the external sensor array, for ease of tuning and maintenance.

For the lazy, here are the sensor angle spacing calculations:
2 pole: 120°
4 pole: 60°
6 pole: 40°
8 pole: 30°
10 pole: 24°
12 pole: 20°
14 pole: 17.142857°

For those of you who will be attempting homebrew sensor arrays, I read that the delta/wye winding matters for sensors. One or the other advances timing, and one or the other requires the 'B' coil sensor to be reversed (not quite sure, but it's in the thread _dV posted).

[sikeston34m]

So has anyone released a sensored outrunner motor yet?

[Arct1k]

Holmes almost has his done.

Very interesting thread, I got 2 questions:
1. If I take 2 outrunners of exactly the same size, poles etc. but one has a kv of 100 and the other one of 200. General rule is: the one with the lower kv has more torque, right? But what if I would install them in a rc-car. The 100kv geared i.e. 10:1 and the 200kv 20:1, so the car would get the same topspeed. Which car will have more torque, the one with the 100kv motor of 200kv motor? Or will it be the same?

2. How can I find out what is the best timing for my motor? Should I try different timings and measure the current of each, and the one with the lowest current is the best timing? Although someone (I believe it was sikeston) in this thread said outrunners prefer high timing... Just use the highest timing possible?


I'm converting my bike to electric, using an CC ESC and turnigy outrunner. I already blew one ESC, so I'm searching for the most SAFE settings for my ESC.

[TexasSP]

Originally Posted by Arct1k

Holmes almost has his done.

x2, and not a minute too soon. I need to have him do a custom built one for me asap.

[johnrobholmes]

My ears were ringing

I've been working on sensored outrunners for years now. It wasn't just as easy as slapping sensors on or in a motor, and positioning is very precise as compared to 2 slot motors. Delta Vs Wye is also a big concern, it is much easier to work with Wye terminated motors as they have a zero timing point that is mechanically accurate. Delta terminated motors essentially auto advance about 20 electrical degrees even with zero mechanical timing. Makes things too touchy for smaller motors.

Here are the first vids of prototyping, 12 slot 8 pole motor. Somehow the sound got stripped off. It is actually pretty quiet as compared to a brushed motor or sensorless startup. I didn't feel like I was bothering anyone at the park.

http://www.youtube.com/watch?v=JevFhBvJ0C0

540 framed motors are first to get rolled out. Next I am doing 28mm outrunners if we can cram sensors in. Might have to go external. I am also working on a 54mm sensored outrunner for Ebikes and robotics uses.


Sensored motors and a motor dyno take up most of my time lately. Hopefully one day I will actually have something to show for it!

[johnrobholmes]

Some more testing vids of them in action

http://www.youtube.com/holmeshobbies

[sikeston34m]

Originally Posted by johnrobholmes

Some more testing vids of them in action

http://www.youtube.com/holmeshobbies

Nice! Nice! Very Nice!

So when are you going to have these available to the public?

I want one!

Sensors are the ultimate addtion to the torque monster outrunner!

I haven't lost my obsession btw.

Hi

I've got a outrunner in my E-Bike. It's a Turnigy 80100 130kv, I think it has 10 poles. I experienced some kind of turbo my bike had. When starting, it pulls good, then when at about 60% speed the motor doesn't spin up anymore (cogging I think) and makes a strange noise, after about 2 seconds I get the "turbo" and the bike accelerates to full speed. I first thought this was due to the batteries sagging too much and the low voltage cut-off kicking in. But after some threatment my LiPo's don't sag as much as in the past. (In the past it sagged down to 28.5V, now to only 36.6V!) Anyway, the cogging part is longer now. Again, at 60% speed it starts with the cogging, but it now takes about 4 seconds to get it going to 100% speed.
All this is done with full throttle, if I go a little more slowly with the throttle to top speed the motor doesn't cog.

Now, the big question: what timing do I need? It's set to normal (5 degrees), can I increase it by about 3 degrees everytime till it doesn't cog anymore or should I go 1 degree everytime? (Oh, and I should increase the timing right? As I've read outrunners like higher timing...)


Thanks

[johnrobholmes]

I'm stuck in a waiting game for the production version, the magnets are getting hard to buy.


You will want to adjust the timing in extremely small increments. 1 degree of mechanical timing is 5 degrees of electrical timing if your motor is 10 pole pair. I would think you have another issue though, maybe a hall out of position a bit or a bad overall position for the sensors. If anything your timing is likely too advanced if you can roll through the throttle and have no issues.