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searching startup procedure for brushless outrunner motor

E

endrophie

Jan 1, 1970
0
hello,

doeß anybody know a special procedure, that an brushless outrunner has
a fast an reliable startup?
Against to engines with inlaying magnets, an outrunner has more torque
and a load with a higher inertia mass. Therefor, the start is more
difficult.
Who knows a strategy or has an idea?

best regards

Endrophie
 
N

Nicholas O. Lindan

Jan 1, 1970
0
I take it the OP is referring to the type of motor refereed to as a
"CD player motor".
doeß anybody know a special procedure, that an brushless outrunner has
a fast an reliable startup?
Against to engines with inlaying magnets, an outrunner has more torque
and a load with a higher inertia mass. Therefor, the start is more
difficult.
Who knows a strategy or has an idea?

There are integrated circuits just for powering these motors.

Look in the model aircraft groups and web sites.

Search w/ Google.
 
There are integrated circuits just for powering these motors.
Hello,

I´m searching for an algorithm for an microcontroller with digital an
analog inputs for BEMF-analyzing.

Best regards

Endrophie
 
J

Jamie Morken

Jan 1, 1970
0
Hi,
hello,

doeß anybody know a special procedure, that an brushless outrunner has
a fast an reliable startup?
Against to engines with inlaying magnets, an outrunner has more torque
and a load with a higher inertia mass. Therefor, the start is more
difficult.
Who knows a strategy or has an idea?

If you don't have hall sensors or a shaft encoder and are using BEMF
sensing to do the commutation, at very low RPM's the BEMF signal will be
weak so you will have to give the motor a kickstart I think. The way I
would try this is to put the motor into a known state first (ie one of
the 6 commutation states for a 3phase brushless DC motor), and then
quickly start doing commutation from that state in the desired
direction, assuming that the motor is able to turn and is not loaded too
high this should work until you get enough BMF for the sensorless
operation to work I think. I have a 3phase brushless DC motor
controller that I made that is waiting for me to test this out on too ;)

cheers,
Jamie
 
J

Jamie Morken

Jan 1, 1970
0
Hi,

Hello,

I´m searching for an algorithm for an microcontroller with digital an
analog inputs for BEMF-analyzing.

This has some good info on that:
http://focus.ti.com/lit/an/spra498/spra498.pdf

They use resistor dividers and RC lowpass filters from the 3 motor
windings and then samples them with the ADC on the microcontroller.

cheers,
Jamie
 
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