flyflie

I just replaced the stock Hummingbird motor with the commended Graupner speed 300, I know everything is set correctly execpt the motor is SPINNING THE OPPOSITE DIRECTION!!! What can this be? should I try reverting the polarity on the motor? that cant be right....

flyflie

Ok this is a reply to my own post but I hope this will help some else. If you have a Hummingbird and you replace the stock motor with a Graupner speed 300 it will spin backward. Weird but true! solution I reverse the connector to the Hummingbird ESC and it seems to be working just fine. Except that now the main motor has too much torque and spins the tail on taking off. I guess now I have to tweak with the gyro and give it more gain.
....

rscamp

You might want to set the timing on the motor for rotation in the opposite direction.

Rob

ziomatrixacs

how do you do that?

rscamp

Next to using an oscilloscope, I would say this is the best way to set the timing on a brushed motor for a heli.

Connect the motor to the batteries. With no load (no prop), rotate the brush assembly (non-drive end) relative to the field (case of the motor) back and forth until you find the point at which minimum current is achieved. This is neutral timing. Record this value and scribe the motor case and end bell to mark this point for future reference. Then rotate the brush assembly opposite the direction of rotation (to advance commutation) until it draws an additional 1/10 the hover current.

For example, say the motor draws 0.2A at neutral timing with no load and it will draw about 5A in a hover, then advance the timing until it draws 0.2 + 0.5 = 0.7A with no load. This should reduce arcing in the commutator and give you just a tad more power.

Rob

kenru

Heck, I just soldered the black wire to the positive post on the Speed 300 and the red lead to the negative terminal. Works fine.

rscamp

Yes it will work okay. Won't be optimum, but okay.

Just slightly more brush and commutator wear and less power. Not a big deal on a Speed 300.

Rob