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Old 11-13-2007, 01:03 AM   #1
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Default sensored vs sensorless brushless

sensored vs sensorless brushless

Guys i am confused of these two types of brushless systems. Can anyone give some infos?
Also how about the ESC for brushless ( sensored & sensorless) are they the same?

which one is better?

help

thanks!!
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Old 11-13-2007, 02:51 AM   #2
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the difference is minimal, but basically a sensorless one just shoves the pulses through the motor, while the sensor one has a sensor to find out where the rotor is, and adjusts the pulses to it's rotation. basically, a sensorless one is cheaper and snappier.
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Old 11-13-2007, 05:08 AM   #3
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The biggest reason for the sensored brushless setups, was that early sensorless systems were very prone to cogging (uneven power delivery). Sensorless systems use back emf to determine rotation and position of the rotor. If pulses are delivered at the wrong time (out of phase) the motor will not be efficient or smooth (cogging).

Sensored systems get around this limitation by knowing where the rotor position is at all times. Even with the newer sensorless systems you can get momentary hesitation especially if you inadvertently loose traction coming into a turn, essentially backing into a turn, when the throttle is applied to power out the the turn it can hesitate slightly. (At least my mamba max setup would)

That scenario does not really cause a problem though, because the delay is very small and you have already lost more time from the mistake anyway.
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Old 11-13-2007, 06:26 AM   #4
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Ahh!!

How is the temperature of the brushless motor compared to brushed?
Which one is hotter? assume the same run time & load.
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Old 11-13-2007, 07:04 PM   #5
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There are way to many variables to answer that question, but, usually a brushless setup properly geared is more efficient and will produce less heat.
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Old 07-27-2009, 01:54 PM   #6
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can an ESC for sensorless motors be used on a sensored motor?
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Old 07-27-2009, 10:52 PM   #7
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Quote:
Originally Posted by joeh5194 View Post
can an ESC for sensorless motors be used on a sensored motor?
yes
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Old 07-28-2009, 08:19 PM   #8
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Yes it can, but obviously it will not start up as smooth without sensor feedback. Most sensorless systems today are so smooth that one can barely tell the difference.
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Old 12-12-2009, 08:44 PM   #9
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Quote:
Originally Posted by bryanleec View Post
sensored vs sensorless brushless
which one is better?
Imagine if this thread was started today!!... LOL.....
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Old 12-13-2009, 12:42 AM   #10
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One important note that hasn't been mentioned is the fact some brushless systems start in sensored mode then switch to sensorless mode. Supposedly this gives the best of both worlds.
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Old 12-13-2009, 05:36 AM   #11
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I have the worst luck with motors/engines and esc's.
If it can cog, I've done it. I will never, ever run a pure sensorless setup ever again. a sensorless setup will run absolutely perfect, until your main comes up in the biggest race of the year. Then it'll accidentally go backwards at the buzzer and collect the entire field in a big pileup.

The software in the esc can make up the difference between smooth and coggy. The Tekins and MMP can get a bad version loaded and act crazy. Thats the fun of flash memory. Even sensored stuff can cogg realy bad if the software has a glitch. We're asking a whole lot from todays Esc's, it's not easy for them to do what they do.

With my Tekin RS the sensored operation seems to give more punch down low. It is used for 21.5, 17.5, 13.5, 10.5 motors. It also gives the Esc different features that are nice to have with slower motors.

In dual mode, it uses sensored operation at low speed , and goes to sensorless as soon as it can. This seems smoother and more precise, a bit wimpy. It's commonly used for 8.5 and faster motors. I don't have much experience with it, I'm currently running sensored only for all my cars.
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Old 03-08-2010, 11:17 PM   #12
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Say, if you're a beginner in touring class racing, spec is stock class 17.5T motor. Should I be looking for the most powerful sensorless ESC and any 17.5T sensorless motor?

Or go with something like a LRP SPX or SXX or Tekin R5 with a tekin 17.5T sensored motor?

Basically you know if you can get some 120Amp sensorless ESC, running 17.5T, you can do quite a lot of damage on racing field.
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