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-   -   Motor Brake? (https://www.rc-monster.com/forum/showthread.php?t=13781)

Shark413 07.24.2008 11:16 PM

Motor Brake?
 
Ok, I have converted several buggies/truggies and I have almost aways used mechanical brakes. I just prefer the feel and ability to adjust the bias. As an experiment I disconnected the mechanical brakes on one of my buggies and reset my Mamba Max ESC brake to 80% (it was set to zero, because I was using the 3rd channel for the mech brakes). When I applied the brakes and pushed the buggy I felt some resistance but the tires would still roll if I pushed hard enough. Thinking something was wrong, I grabbed my truggy and performed the same thing and again I could easily push the truggy with full brake. Thinking it had something to do with the mechanical setup I was using I grabbed my CRT.5 which I have always used motor only brake, again I could push the CRT.5 with some resistance but no lock-up, even at 100% brake on the ESC. I tried recalibrating the ESC with my radio, checked the EPA and trim, reset the radio to the default settings, same results. With mechanical brakes I could easily lock up all four wheels with my EPA set to max. Is it normal not to be able to get the motor brake to lock-up? I normally never run the mechanical brakes to the point where they lock-up but I could if I wanted to, which doesn't appear to be an option with motor only brake. Can anyone provide feedback regarding motor only brake? Are you guys able to set your motor only brake so the wheels almost lock-up?

brushlessboy16 07.24.2008 11:20 PM

i think the esc sees the emf pulse and tries to slow it to where there is no emf

BrianG 07.25.2008 12:40 AM

Take any BL motor, short all three phases (unhook the ESC first). Feel the resistance as you turn it manually. That's the max brake effect you'll get with the motor (unless the ESC applies reverse voltage to the motor to brake). The faster it is spinning the more braking force is generated. Going really really slow, the motor hardly brakes, but then again, unless you're crawling or on a steep incline, it hardly matters IMO.

Shark413 07.25.2008 03:27 AM

So Brian, if the motor is spinning faster the braking effect will be greater? That sounds logical, because on the track my CRT.5 feels like it has plenty of brake. If that is how it works, then it reinforces why I prefer mechanical brakes, which are very consistant and are not dependant on how fast the motor is spinning or how thick the diff oil is. That being said, I plan on testing a setup in my buggy/truggy that uses motor brake on the rear and mechanical brake on the front. I will make runs down a measured distance and at the same point apply max braking force. I will see what the stopping distances are between motor only, Full mechanical brakes and a hybrid motor only/mechanical setup. The reason for all of this is I am trying to find a happy medium between strong consistant brakes and reliable function. Mechanical brakes are strong and consistant, but add complexity and weight. Also having to space out the motor to clear the mechanical rear disc puts additional strain on the front motor bearing (I had to replace my Neu front bearing after only 3 months use, I believe this is related to my mechanical brake setup). On the other hand, motor only braking works, is very simple and reliable, but it is not as consistant, not as adjustable and could add stress to the electrical system.


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