Sensored vs. Sensorless
07-25-2008, 03:33 AM
#46
Tech Initiate
SpeedPassion has many excellent designs for how to make the speedo more powerful and easier to use. GT series speedos are the result of deep-cooperation of Speedpassion and Hobbywing, so from this point of view, Speedpassion and Hobbywing is a union to make top-level speedos for car.
Except the speedos for competitive racing, we also work together to make some budget-friendly products,such as EZRUN series mentioned above. we hope that the brushless syetem will soonly become more and more cheap, more and more reliable, just like the brushelss speed controllers are so popular in aircraft and helis, these products are cheap but with very good performance, we do believe that the same evolution will be happened in RC car/truck fields.
Except the speedos for competitive racing, we also work together to make some budget-friendly products,such as EZRUN series mentioned above. we hope that the brushless syetem will soonly become more and more cheap, more and more reliable, just like the brushelss speed controllers are so popular in aircraft and helis, these products are cheap but with very good performance, we do believe that the same evolution will be happened in RC car/truck fields.
07-25-2008, 03:59 AM
#47
interesting thread.
As far as I'm concerned, my GM Genius 95 ESC is used sensorless. And until now it has worked perfectly, even at the start, not the least amount of cogging or hesitation.
M.Hoffer on the GM BL thread keeps repeating that NONE of the GM team drivers use sensors .." NO DIFFERENCE ", he says... and I do believe him !
However I run a "mod" (5.5) motor with this esc, so maybe for "stock", 13.5-17.5 racing, the sensors would give an advantage at the start... For this reason the tekin "dual mode " as named earlier, sounds like a great idea.
As far as I'm concerned, my GM Genius 95 ESC is used sensorless. And until now it has worked perfectly, even at the start, not the least amount of cogging or hesitation.
M.Hoffer on the GM BL thread keeps repeating that NONE of the GM team drivers use sensors .." NO DIFFERENCE ", he says... and I do believe him !
However I run a "mod" (5.5) motor with this esc, so maybe for "stock", 13.5-17.5 racing, the sensors would give an advantage at the start... For this reason the tekin "dual mode " as named earlier, sounds like a great idea.
07-25-2008, 04:24 AM
#48
my castle unit was not bad for 2wd mod, however i wouldve liked somethin more smooth like a brushed, that and starts were dreadful. in offroad sometimes its about ur electronics ability to shed power if you cant afford a spare motor thats milder
R
R
07-25-2008, 04:45 AM
#49
Tech Adept
@ heretic, car brushless system is at a stage as the airplane were in the beginning, 7 years ago.
Car systems work very well if used the ESC and motor of the same brand. if you change the brand of one of the parts things will happen.
GM systems are great and work perfectly sensorless at least with GM motors.
My Mamba system works perfectly and is sensorless, and until today I have never used a system so powerful and so smooth as Mamba Max ESC and Mamba 7700 motor. It was to much power for the track I had to change to 6900 motor.
But now I am in the Stock Nacional championship with 9,5T brushless motor. As I could not use a Mamba motor i bought a GM and use with Mamba Esc but the starts at the grid were not perfect, so I bought a SP GT ESC and I am using it with sensors. Everything is working fine but i have the feeling that i have done a step back in thecnology using a brushless system this way.
Car systems work very well if used the ESC and motor of the same brand. if you change the brand of one of the parts things will happen.
GM systems are great and work perfectly sensorless at least with GM motors.
My Mamba system works perfectly and is sensorless, and until today I have never used a system so powerful and so smooth as Mamba Max ESC and Mamba 7700 motor. It was to much power for the track I had to change to 6900 motor.
But now I am in the Stock Nacional championship with 9,5T brushless motor. As I could not use a Mamba motor i bought a GM and use with Mamba Esc but the starts at the grid were not perfect, so I bought a SP GT ESC and I am using it with sensors. Everything is working fine but i have the feeling that i have done a step back in thecnology using a brushless system this way.
07-25-2008, 05:59 AM
#50
My Mamba max speedo with a GM 7T delta runs so smooth as when i was running the MM7700 motor.
07-25-2008, 06:46 AM
#51
Tech Fanatic
I run a GM Genius with a GM 7 Delta and Orion 10.5
I have tried to run both sensored and unsensored ... there is no noticable diffrence on the track or on the bench, so I run without the extra wires
I have tried to run both sensored and unsensored ... there is no noticable diffrence on the track or on the bench, so I run without the extra wires
07-25-2008, 11:43 AM
#52
Tech Regular
delta wound "stock"
Hi, I know it wouldn't be legal for ROAR events but I"m looking for a delta wound 540 size motor that comes close to a 17.5. I've located a Feigao 16S that has a KV of 2218. Novak's 17.5 has a KV of 2200. I want the Delta because ROAR 17.5 motors and sensorless speed controls don't seem to get along to well. Thanks, Don
07-25-2008, 04:28 PM
#53
Tech Regular
bump
07-25-2008, 05:58 PM
#54
Tech Addict
This is very interesting thread. I don't think I've ever seen as many supposedly informed people telling others as many wrong things.
To answer the original question. The difference is, as the name suggests, that sensored motors have sensors built-in and sensorless don't. These sensors are used by the speed control to sense the position of the rotor (the thing inside the motor that rotates and we fasten the pinion to
). The difference in the motor (aside from the physical presence of sensors) and the power it produces is none. You could remove the sensors, or leave them unplugged, and the motor would give you exactly the same amount of power at exactly the same load, voltage and frequency under stable conditions. Why wouldn't it, it's exactly the same motor. So the difference lies mostly in the speed controls.
Speed controls for sensorless motors use advanced methods for guessing the position of the rotor, while the sensored, as said before, use sensors.
If we compare it to bouncing a ball, then sensored speed controls watch the ball land and bounce up while sensorless speed controls hears the thumps. Sensored speed controls may also hear the thumps but sensorless speed controls are blind. Neither of them knows how high the ball goes but they can both calculate it by measuring the time between bounces.
In real life there is little difference these days but early sensorless systems were horrible in starting from dead stop. The car would stutter and sometimes even go backwards. I remember a Mamba system (sensorless) that could never get car rolling if I jammed the throttle wide open from dead stop, I had to roll on the throttle to get the car rolling, and if the car was pointed up a steep hill, even rolling on the throttle wasn't enough to get it rolling. The LRP sensored system that replaced the Mamba system has never had trouble getting the car rolling. I might be able to fix the Mamba system by uploading new software but while the LRP system works perfectly I have no need.
The rules for brushless motor were not written by Roar on a blank sheet. They were written using suggestions from brushless motor manufacturers. It was long time ago and there were few manufacturers interested in the market, which is why the rules suited one manufacturer very well.
To answer the original question. The difference is, as the name suggests, that sensored motors have sensors built-in and sensorless don't. These sensors are used by the speed control to sense the position of the rotor (the thing inside the motor that rotates and we fasten the pinion to
). The difference in the motor (aside from the physical presence of sensors) and the power it produces is none. You could remove the sensors, or leave them unplugged, and the motor would give you exactly the same amount of power at exactly the same load, voltage and frequency under stable conditions. Why wouldn't it, it's exactly the same motor. So the difference lies mostly in the speed controls.Speed controls for sensorless motors use advanced methods for guessing the position of the rotor, while the sensored, as said before, use sensors.
If we compare it to bouncing a ball, then sensored speed controls watch the ball land and bounce up while sensorless speed controls hears the thumps. Sensored speed controls may also hear the thumps but sensorless speed controls are blind. Neither of them knows how high the ball goes but they can both calculate it by measuring the time between bounces.
In real life there is little difference these days but early sensorless systems were horrible in starting from dead stop. The car would stutter and sometimes even go backwards. I remember a Mamba system (sensorless) that could never get car rolling if I jammed the throttle wide open from dead stop, I had to roll on the throttle to get the car rolling, and if the car was pointed up a steep hill, even rolling on the throttle wasn't enough to get it rolling. The LRP sensored system that replaced the Mamba system has never had trouble getting the car rolling. I might be able to fix the Mamba system by uploading new software but while the LRP system works perfectly I have no need.
The rules for brushless motor were not written by Roar on a blank sheet. They were written using suggestions from brushless motor manufacturers. It was long time ago and there were few manufacturers interested in the market, which is why the rules suited one manufacturer very well.
Last edited by andsetinn; 07-26-2008 at 06:06 AM. Reason: spellcheck
07-25-2008, 06:22 PM
#55
Tech Regular
The reason I posted my question in this thread was because of the ongoing discussion about wye and delta motors. I was hoping someone could lend me their expertise? Don
07-26-2008, 06:05 AM
#56
Tech Addict
In Delta connection you get full voltage across each winding. In Star the voltage gets shared by the windings. This makes the Delta connection more powerful. It is, if I remember correctly about 1.7 times more powerful, with the same windings. The Delta motor also turns faster, with the same windings. The Star motor has more starting torque, with the same windings. But you can design 2 motors, one with Star connection and the other with Delta connection and these motor can have identical power output. They do not have the same windings or rotor but they can have the same power.
If you want 500 watt motor, you can buy Delta motor that is 500 watts and you can also buy Star motor that is 500 watts. 500 watts and 500 watts is the same power no matter which connection you use.
I always look at the wattage when I buy brushless motor. The turn number is not a good guide to the power of the motor. The KV number tells you roughly how to gear it. And the material of the rotor, sintered or bonded only really tells you how much heat the motor can withstand. Although one can give you slightly more power you can design a motor that uses the other material and gives you even more power.
If you're willing to have six powerwires to the motor, it's easy to build ESC that switches between star and delta connection on the fly, giving you best of both worlds.
If you want 500 watt motor, you can buy Delta motor that is 500 watts and you can also buy Star motor that is 500 watts. 500 watts and 500 watts is the same power no matter which connection you use.
I always look at the wattage when I buy brushless motor. The turn number is not a good guide to the power of the motor. The KV number tells you roughly how to gear it. And the material of the rotor, sintered or bonded only really tells you how much heat the motor can withstand. Although one can give you slightly more power you can design a motor that uses the other material and gives you even more power.
If you're willing to have six powerwires to the motor, it's easy to build ESC that switches between star and delta connection on the fly, giving you best of both worlds.
07-26-2008, 07:44 AM
#57
Tech Regular
Thanks, it looks as though not to many people are trying to do what I want to do. I have a Mamba Sidewinder (1/10) that I want to use in a TC for "stock" class. I already know that it won't drive a 17.5 to well.(cogging) So I'm looking for a Delta wind to get as close as I can. I was hoping the Feigao 16S (KV 2218) would suffice. The idea was to find a 540 size Delta wind motor that my Sidewinder would drive successfully and then hope that if I get to a race they would let me run it in "stock" class. Thanks, Don
07-26-2008, 10:58 AM
#59
Tech Addict
I'm not familiar with Lehner motors.
The names Delta and Wye refer to the way the windings inside the motors are connected. There are normally 3 sets of windings, each set of windings has 2 ends.
In Delta connection they're connected in "triangle" (Delta is, if I remember correctly, the Greek or Latin word for triangle) so that each windings end connects to the end of the next winding. So you have 3 connections and 3 motorwires each connected to a connection.
In Wye they're connected in a "star" or Y if you prefer. One end of each winding is connected together and the motorwires are connected to the other end of the winding.
If you take both ends of the windings out of the motor you can change the connection externally (duh) and you can design ESC that changes the connections on the fly.
To answer the question, you're not having the Delta/Wye in the motor but in the speed control.
I look at Watts to determine the power of the motor and KV to determine the gearing. Turns only partially tell you the power of the motor and KV don't tell you how much power it has, only how fast it turns at certain voltage, usually at no load.
The names Delta and Wye refer to the way the windings inside the motors are connected. There are normally 3 sets of windings, each set of windings has 2 ends.
In Delta connection they're connected in "triangle" (Delta is, if I remember correctly, the Greek or Latin word for triangle) so that each windings end connects to the end of the next winding. So you have 3 connections and 3 motorwires each connected to a connection.
In Wye they're connected in a "star" or Y if you prefer. One end of each winding is connected together and the motorwires are connected to the other end of the winding.
If you take both ends of the windings out of the motor you can change the connection externally (duh) and you can design ESC that changes the connections on the fly.
To answer the question, you're not having the Delta/Wye in the motor but in the speed control.
I look at Watts to determine the power of the motor and KV to determine the gearing. Turns only partially tell you the power of the motor and KV don't tell you how much power it has, only how fast it turns at certain voltage, usually at no load.
07-26-2008, 11:01 AM
#60
Tech Addict
Thanks, it looks as though not to many people are trying to do what I want to do. I have a Mamba Sidewinder (1/10) that I want to use in a TC for "stock" class. I already know that it won't drive a 17.5 to well.(cogging) So I'm looking for a Delta wind to get as close as I can. I was hoping the Feigao 16S (KV 2218) would suffice. The idea was to find a 540 size Delta wind motor that my Sidewinder would drive successfully and then hope that if I get to a race they would let me run it in "stock" class. Thanks, Don