Sensor vs non-sensored BL motors
 

What is the difference between the Brushless sonsored and non sensored motors? Is one better then the other?

I asked BrianG this question a little while ago, and this was his response:

The search button is your friend..........sensored motors have sensors which tell the esc what position the rotor is in.this helps with smoother starts and most of the time it gives you the ability to move at a crawling speed with no cogging...
i personally like non sensored, with a good esc a non sensored motor will performe similar to a sensored

Ok, understood now what is cogging and how do you prevent this or minimize this?

There aren't any really good (REALLY good) brushless motors out there that are sensored, all the good ones (and high powered) are sensorless.

cogging is were the esc cannot start the rotor....this can be caused by high current draw...or that your batteries cannot supply the needed current. a sensorless motor has a minimum rpm it can turn at so anything lower than this will appear to cogg

I'm using a MM esc and know there are software adjustments we can make can the throttle curves be adjusted to reduce the cogging? Just thought I would ask since I know quite a few guys here use the MM.

I think it's more the esc's software/hardware to detecting rpm/rotor position which causes cogging... because, even if the motor is spinning at say 60rpm, there will be a voltage generated, albeit, small potential. It's just up to the tech of the controller to be able to 'see' this potential, past all the other electrical noise, w/e.

The mamba maxx for example simple has a minimum RPM it starts the motor at,my guess is that it's easier that way to read/measure the back EMF with less faults.

That has got nothing to do with sensorless or sensored, I think it would be easier to make an ultra high power esc/motor combo sensored. it's more a matter of costs.

Lack of high end sensored motors most likely stems from the lack of high end sensored speed controllers. Griffinru made a feigao work with a novak hv using the hv motor as a sensor and putting the leads to the feigao. Neither are high end, but I bet it had great low speed driveability! The novak esc is supposed to be quite good, just the motors are a little small for heavier applications.

Well, with the new sintered rotors, their motors preform pretty well.

But griffinru finally succeeded in using a sensored Feigao motor instead of using the two motors.

I think the only way for high powered sensored systems to get going is for companies like Neu/Lehner and others to make their motors with built in sensors... after all, the Neu's have decent gap in the front of the motors inside, this space is perfect to throw in a hall sensor...

I guess there is little incentive for them to do this, seeing as they made there motors for a certain crowd... aircrafts. :tongue:

The startup is pretty dang good on sensorless, I just don't see anybody wanting to put effort into sensored motors for hobby use (unless they like to hold on to old tech as the only way worth pursuing).

I wouldn't call it 'old tech'... whats so old about a sensor? The motor would still be the very same.

Do companies still make sensored motors? Which ones?

Hall effect sensors were developed in the 1950's, and are most useful for slow speed commutation (less than 1/10kv). I think it is safe to assume that few people stay in that throttle range for more than a split second in this forum. Of course the best combination would be a sensored system that switched to sensorless at a certain rpm for best efficiency, but that would only add weight and complication IMO. Stepper motors work without sensors, and they are very precise. We probably wont see stepper commutation cross over into our hobby though, the motor and ESC would have to be matched so that the winds weren't smoked. If I remember correctly stepper motors are also high resistance too.