AVR-Chat

Dave Mucha wrote:
> Hi all,
> 
> I'm trying to find more data about the R/C throttle control.
> 
> as I am to understand, the control input to an
> ElectronicSpeedController (ESC) is over a repetitive 20mS frame.  and
> in that frame there is a range between 0.5 and 2.0mS that is the value.  
> 
> That would make it so 0.5mS is a zero speed and 2.0mS would be 100% speed.
> 
> am I correct on this?
> does anyone have a schematic for an ESC for a burshless motor ?
> 
> I'm looking for a 25,000 RPM motor to use on a PCB drilling machine
> and these seem small enough and high speed enough to do the job. 
> Unfortunatly, the combination of motor and ESC can run upwards of $1750 !
> 
> Any comments or suggestion are welcome.
> 
> Dave

If it's a 3-phase induction motor, you just need to generate a 3-phase sinewave
drive where the amplitude increases with frequency, and slowly ramp up the
frequency when starting the motor.