AC motor - Know how many times it turned

Greetings,

I'm trying to get the information from an AC 3 phase motor. The motor is used to roll windows up and down. I know that X turns correspond to Y cm and that the window has Z cm high.

I would like to know what kind of potentiometer can I use to know how many turns has the motor done.

I'm speaking about potentiometer because I've already seen once one motor using a potentiometer, but I don't know what kind of pot will it be.

The image of the potentiometer is here: http://web.ist.utl.pt/pedro.m.s.oliveira/20150218_112912.jpg

I don't need to use a Pot. If you know any other sensor I can use, for me it's ok.

Using a Pot, by now, i think I can only check one solution: the output shaft driving a gear so the complete closing of the windows will be less than the common pot will turn, so I won't damage the pot. And then, from the pot resistance, make the calculations.

But I think there will be an easier way.

Thank you very much,
Pedro Oliveira

Pots are either about 300 degrees of turn, or there are ten-turn ones (rare, expensive).

For what you want to do an encoder and homing switch/sensor is normally used.

There's no reason to expect the device in the diagram to be a pot. Its got three wires,
but that proves little.

FWIW it appears to be a Bourns 3590 (10 turn) potentiometer.

Pedro_Oliveira:
I would like to know what kind of potentiometer can I use to know how many turns has the motor done.

From the picture you posted above you don't need to know how many turns the shaft has done, all you need to know is the pots resistance readings at blinds up and blinds down and just turn the motor on (in the right direction) and keep reading the pot's resistance until it matches the resistance your looking for.

Thank you very much,
Pedro