On 06/29/2011 03:58 PM, Jan de Jong wrote:
> In the section below you describe PWM with a pulse width of less than
> 100% - thus running the motor at less than full speed.
> This surprises me as electric full speed pitch change is slow compared
> to hydraulic pitch change already.
> Is there ever a reason to slow the electric motor down?
I'm sure Mark Burton can answer this question better. But as I
understand the operation is that with large RPM mismatches the motor is
fed with a higher duty cycle, and with smaller RPM mismatches the motor
is run more slowly, to avoid pitch hunting and overshoots. At full speed
the motor runs out for a considerable time after cutting the power, so
correcting small RPM changes can only be done with a very slow running
pitch change motor.
Do not underestimate the speed of the woodcomp pitch motor: It will go
---From fully fine to fully coarse within one second. This only applies to
the propellers with reverse or feather options.
I have not much experience with hydraulic props, but the one I have
flown was considerably slower and more instable than my Woodcomp/Smart
combination.
Frans
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