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Old 07-12-2014, 11:49 AM   #16
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I thought you weren't supposed to free rev the motor.
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Old 07-12-2014, 12:01 PM   #17
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I thought you weren't supposed to free rev the motor.
A 17.5 or 21.5 reving the motor in the car won't over rev it. That's with a 4 wheels on the car.
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Old 07-19-2014, 02:40 AM   #18
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Originally Posted by vivo quevas View Post
A 17.5 or 21.5 reving the motor in the car won't over rev it. That's with a 4 wheels on the car.
A higher turn motor is not likely to over rev and lead to rotor damage. A low turn motor is a different story though. The rotor is the victim in this scenario and is basically the same in all modern race motors. A low turn stator will spin the same rotor much faster than a high turn stator. Free running a given motor is relative to the potential RPM the stator can induce. Therefore a 17.5t will never induce enough RPM to damage a quality rotor that normally would see higher RPM in a 4.5t, even under load.
If you are still concerned, use a 1 cell battery or an adjustable DC power supply.
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Old 11-29-2014, 01:49 AM   #19
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When shimming the rotor, is it best to get it as close to the sensor board as possible or are you looking for the magnetic center (is that what its called?) like brushed motors like?
Like to know too. Seems you can only get one or the other. When I try to center the rotor in the magnetic field, it's like 2+mm away from the sensor, which is not optimal...
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Old 11-29-2014, 02:57 AM   #20
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Zero timing + 10 degree

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Old 11-29-2014, 03:29 PM   #21
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Like to know too. Seems you can only get one or the other. When I try to center the rotor in the magnetic field, it's like 2+mm away from the sensor, which is not optimal...
Why is that not optimal?
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Old 11-29-2014, 04:10 PM   #22
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Why is that not optimal?
The general rule of thumb is to get the rotor about 0.8-1.0mm from the sensor board. If it's too far, it's said that you lose torque. But on some motors, when you shim it this way, you can't center the rotor in the magnetic field. This will cost you some rpm loss since there will be constant side pressure on the bearing.

It'd be nice if someone can make a depth adjustable sensor board.
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Old 11-29-2014, 06:45 PM   #23
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Originally Posted by redbones View Post
The general rule of thumb is to get the rotor about 0.8-1.0mm from the sensor board. If it's too far, it's said that you lose torque.
Why would it affect torque?
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Old 11-29-2014, 07:32 PM   #24
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Why would it affect torque?
Not sure of the mechanics behind it, but I read this:

http://speedyrc.blogspot.com/2013/11...otor-open.html
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Old 11-30-2014, 04:02 AM   #25
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Not sure of the mechanics behind it, but I read this:

http://speedyrc.blogspot.com/2013/11...otor-open.html
Thanks for the link. Unfortunately there was no explanation given.

Until I hear some logical reasoning, I would not give any credence to this claim.
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Old 11-30-2014, 11:06 AM   #26
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Agreed. Until I find some info that is fact based, I'm just gonna give the rotor a little room to find itself, like a teenager....
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Old 12-01-2014, 01:55 AM   #27
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When I've had a rotor that was a bit far from the sensor board it seemed more likely to cog etc.
If you have problems with the rotor not being anywhere near centre of stator or near the sensor board you need to buy a decent motor instead
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Old 12-01-2014, 02:43 AM   #28
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Agreed. Until I find some info that is fact based, I'm just gonna give the rotor a little room to find itself, like a teenager....
The way I see it, if the sensor is too far, it won't read as accurately the rotor position, hence wrong timing might be applied.

Skiddins' post above tends to suggest that if the rotor is too far away the ESC will go into sensorless mode hence the cogging (or apply the wrong timing with the same outcome).

Buy like he says a decent motor or mess with yours (machine the housing down a bit so you can center it whilst bringing it closer to the sensor board - fun!).
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Old 09-20-2017, 12:12 PM   #29
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Default Rotor polishing

Okay so im liking the tuning aspect of rebuildable brushless motors.
Working on a Novak Ballistic 13.5T red wire 540 motor. I have balanced the rotor by hand as i dont have the funds to do it properly.
Also Polished the rotor by spinning it up in a drill to low rpm and sanding, metal polish etc.
Anyone else had experience with balancing?
Haven't powered it up yet as im rewiring my havoc Pro Esc.
Was the Vulcan their Best Tc Motor??
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Old 09-20-2017, 12:13 PM   #30
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And what about a 14mm rotor used in tc racing??
Im thinking it will kick butt. Way bigger magnet. More acceleration... ?
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