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Old 06-21-2011, 09:07 AM   #1
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Default brushless timing query

I just have a couple of questions guys and I hope someone could point me into the right direction or ideas.......

1. Static timing on the endbell yes??
2. Dynamic timing is from the speed control??
3. I have a tekin rs pro so it has timing advance for dual and sensorless mode.
4. I run in sensored only mode so I have turbo and boost functions.
5. I am running a 17.5 motor
6. Temp I know we go by on speed control and motor but,

Ok now if there is three phases in a brushless motor adding to 360* if we were to advance our static timing on the endbell and then dynamically adding timing if we were to push anymore more than 60* advance we would be pushing into the next phase and sending back to much EMF so causing heat and slowing down??

So if 60* is in total or can we run static timing of say 45* plus what we can add dynamically are we pushing into the next phase of the motor or what do other ppl think or do instead??

Timing is fun to play with in boosted classes and different ways of applying it.
So if we were to retard the timing on the endbell back to 0* or minus 45* then use the speed control to add all the timing dynamically as that will give us all the LOW end torque we could ever want (brushless motors allways never lose torque top end if you have the battery power to push it as adding timing also pushes torque) so the smaller fdr we can run which means bigger rollout then when the timing is added does it go faster than having high static timing and small amounts of dynamic timing??

Every brushless motor will give EMF back to the speed control and limit anymore power to go to the motor as thats how sensorless setups add timing from back EMF but cogging and so on is a problem thats why they created dual mode on some speed controls to start in sensored mode and then run in sensorless mode....

Anyone want to shed any light on their thoughts as I really dont think we have cracked the surface of this???

Looking forward to some reading
Fordy
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Old 06-21-2011, 10:22 PM   #2
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Default

Originally Posted by jjfo80
I just have a couple of questions guys and I hope someone could point me into the right direction or ideas.......

1. Static timing on the endbell yes??
2. Dynamic timing is from the speed control??
3. I have a tekin rs pro so it has timing advance for dual and sensorless mode.
4. I run in sensored only mode so I have turbo and boost functions.
5. I am running a 17.5 motor
6. Temp I know we go by on speed control and motor but,

1 & 2 are in general correct, well except it’s possible for the speedo to also have static timing. (Not fully up on Tekin details)

Ok now if there is three phases in a brushless motor adding to 360* if we were to advance our static timing on the endbell and then dynamically adding timing if we were to push anymore more than 60* advance we would be pushing into the next phase and sending back to much EMF so causing heat and slowing down??

So if 60* is in total or can we run static timing of say 45* plus what we can add dynamically are we pushing into the next phase of the motor or what do other ppl think or do instead??

One can certainly over time a motor, but the limits are not that straightforward. Your case assumes a static analysis. One of the reasons timing advance works is due to the inductance in the motor windings. This inductance dynamically limits the rate at which the current can build up, delays it in a sense, at higher speeds the effective delay is larger in terms of motor rotation. Thus dynamic timing, so the current has time to build up at higher speeds.

Timing is fun to play with in boosted classes and different ways of applying it.
So if we were to retard the timing on the endbell back to 0* or minus 45* then use the speed control to add all the timing dynamically as that will give us all the LOW end torque we could ever want (brushless motors allways never lose torque top end if you have the battery power to push it as adding timing also pushes torque) so the smaller fdr we can run which means bigger rollout then when the timing is added does it go faster than having high static timing and small amounts of dynamic timing??

Concept wise that’s the whole idea, but like most everything don’t overdo it. Don’t think negative timing is going to work too well for example. The torque and power will peak with the ideal positive timing at each RPM, but then drop off if too much. Thus the game/fun, find that ideal peak over the entire RPM range, intertwined with gearing (as always). Note in practice a higher FDR is normally used, tracks are only so big after all.

Every brushless motor will give EMF back to the speed control and limit anymore power to go to the motor as thats how sensorless setups add timing from back EMF but cogging and so on is a problem thats why they created dual mode on some speed controls to start in sensored mode and then run in sensorless mode....

Anyone want to shed any light on their thoughts as I really dont think we have cracked the surface of this???

Looking forward to some reading
Fordy

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