Proof of concept:
Optical, why bother
We have all seen hall sensor fitted to RC outrunners that work, so why develop an optical system?
Hall sensors can be fitted externally or internally, each has its pros and cons.
The list below is written with the very popular Turnigy 80-100 outrunner in mind, but many of the points will apply equally to other outrunners.
External Hall Sensors placed around the bell:Pros
- Timing can be adjusted by moving the sensors,
- Sensors are kept away from any heat generated by the motor.
Cons
- Difficult or impossible to operate at high power levels (for Turnigy 80-100,greater than about 3kw), due to interference from stator flux.
- Difficult to achieve accurate angular spacing required between the sensors without precision machining
Internal Hall Sensors, glued in stator slots:Pros
- Less prone to interference from stator flux, so will operate at higher power.
- No precision bracket machining required.
Cons
- Not adjustable.
- Motor needs to be dismantled to install them.
- Sensors subjected to heat generated by the stator.
- Difficult to determine which slot to start with to achieve neutral or +-30 edegree timing.
Enter the optical commutation sensor design…..
- This is an external system, so it is possible to move the sensors to adjust the timing.
- It is not susceptable to magnetic interference, so will work with high power motors.
- It does not require precision components to be machined, -the encoder strip is printed by a computer
- The connections and electrical signals are the same as hall sensor systems, so it is compatable with existing controllers
… so it all looks quite promising ?
http://www.youtube.com/watch?v=EHv8tApfOSo
[youtube]EHv8tApfOSo[/youtube]
I will try and get one installed on my RC bike soon and we will see how it works in the real world.
If everything is good, and there is enough interest, I will get a batch of PCBs made and offer kits to people.
Astro 32xx version also in the pipeline…
Burtie
Optical, why bother
We have all seen hall sensor fitted to RC outrunners that work, so why develop an optical system?
Hall sensors can be fitted externally or internally, each has its pros and cons.
The list below is written with the very popular Turnigy 80-100 outrunner in mind, but many of the points will apply equally to other outrunners.
External Hall Sensors placed around the bell:Pros
- Timing can be adjusted by moving the sensors,
- Sensors are kept away from any heat generated by the motor.
Cons
- Difficult or impossible to operate at high power levels (for Turnigy 80-100,greater than about 3kw), due to interference from stator flux.
- Difficult to achieve accurate angular spacing required between the sensors without precision machining
Internal Hall Sensors, glued in stator slots:Pros
- Less prone to interference from stator flux, so will operate at higher power.
- No precision bracket machining required.
Cons
- Not adjustable.
- Motor needs to be dismantled to install them.
- Sensors subjected to heat generated by the stator.
- Difficult to determine which slot to start with to achieve neutral or +-30 edegree timing.
Enter the optical commutation sensor design…..
- This is an external system, so it is possible to move the sensors to adjust the timing.
- It is not susceptable to magnetic interference, so will work with high power motors.
- It does not require precision components to be machined, -the encoder strip is printed by a computer
- The connections and electrical signals are the same as hall sensor systems, so it is compatable with existing controllers
… so it all looks quite promising ?
http://www.youtube.com/watch?v=EHv8tApfOSo
[youtube]EHv8tApfOSo[/youtube]
I will try and get one installed on my RC bike soon and we will see how it works in the real world.
If everything is good, and there is enough interest, I will get a batch of PCBs made and offer kits to people.
Astro 32xx version also in the pipeline…
Burtie