Motor + ESC Timing and frequency

[Gary Murphy 1]

I am new to electrics and just got a motor + esc combo.

The motor manual says the timing is 5 degs and 8 KHz is listed as freq.

The ESC is programmable via PC/Laptop. The timing is easily changeable to the 5 degs of motor BUT nothing is listed for frequency. The esc manual does not even mention freq. A look online found the freq of esc to be 18 KHz .

Is this ok? any info on timing and freq setting would be good

[Peter Beeney]

Gary,

My take on both the timing aspect and the frequency of brushless motors is that as far as aeromodellers are concerned they are both relatively unimportant; it’s perhaps only when you are looking for the optimum performance that adjusting the timing can make the difference. However, as with just about everything else in life, it has to be at least a small compromise, so some care is needed, altering the one condition may result in other unwanted effects. As you say, you can change the ESC setting to suit but I think it’s most unlikely you will be able to change the frequency. Indeed, I’m not sure that you would ever want to change it. 5 degrees of timing is low, is your motor a low pole count high kV lump? Some ESCs have an auto timing setting, this may give you the best all round performance; no harm in trying.

I suspect the 8KHz frequency figure may suggest that this is the lowest to use, or perhaps it’s to do with the resonant frequency of the motor; either way I’m sure I wouldn’t be poggering over this too much.

A name/description for the combo would be very useful…

The frequency is always in the background, this is the speed at which the Pulse Width Modulation, (PWM), signal is being generated within the ESC to regulate the voltage, (and thus the speed), being applied to the motor. This switches the current on and off in a series of equal length pluses, with the on/off time variable in each pulse.This pulse train can tend to raise the temperature on the ESC, though. When the motor is on full chat it’s getting all the available battery voltage so there is no modulating signal present. These oscillators are usually graded in steps of 2KHz; 4KHz; 8KHz; 16KHz and so on; 16KHz is a popular ESC figure but your’s may well be an exception to the rule. But again, all this is of little consequence anyway…

Hope this is of some use and as stated, these are just my own views and ideas, they may not all be correct so I will apologise for any mistakes made in advance.

PB