Quote:
Simple and short, my opinion on braking.
BL motor braking: (most likely mechanics)
first: a shorted motor has incredible resistance from turning, and, the faster it spins, the more resistance it has.
- Using full motor shorting for braking would undoubtedly flip an R/C car over it's lid with ease.
- So, you need to control this shorting in order to control the motor shaft resistance, to create an average resistance or torque.
-Along came PWM... the controller sets up the FET's to unify all motor phases to create a short. So the controller will change PWM duty cycle depending on throttle position... so anywhere between say 1% to 95% (for ABS, guessing) duty cycle for proportional braking.
-These latest controllers (like the Quark) most likely have some good algorithms for braking.
This is just my simple theory on motor braking, not going into detail what happens in FET's.
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And this is correct.
BTW, the ABS can 'easely' be programmed; if a motor turns, it's a generator, and by the amount of energy it produces the speed of the turning motor can be determined. Slowing a vehicle down usually take a certain amount of time and the controller can measure the energy that the motor is still producing.
Who ever ran a quark on a rather direct drive vehicle (short gearing ratio) and a low KV motor knows that the brakes work too hard. It's just a matter of software, this software assumes a certain brake power is needed.
Again; that guy at schulze (who developped his brushless controllers) told me the energy was stored back into the batteries. No need to think he was wrong. He seemed very interested in my runtime of my savage, when i told him i was going to use the mechanical brake instead of the motorbrake. So something must be happening with the batteries, agree?
And zero; if the energy is stored in the motor like you suggested, why does a controller get hotter if you use the motorbrake? (the motor would get hotter too, no doubt, but with your theory ONLY the motor would get hotter.)
@ artur; why does the controller need to know the possition of the rotor? all three phases can be shorted with PWM instead of going the complex route of following the stator.