[Khaled.Hosam]

hii all, I bought a used DC motor with encoder, and I can't determine which of them is Vcc, ground, control.. can anyone helps me in this
thanx all

[Al_The_Man]

One way is to see if you can identify any IC's on the encoder and determine which is the +5v and common and identify the appropriate wire colour, you can then power it up and determine signals by meter or 'scope.
Is there a motor or encoder make or model?
Al.

[Khaled.Hosam]

it got no IC on the motor as the encoder is embedded in it, but there are 3 colored wires from it, these colors are: yellow, brown and blue!!!

[Al_The_Man]

It cannot be a quadrature encoder as at least 4 conductors are required.
A resolver requires 6, unless it is a digital tach of some kind?
Or is it the motor conductors you are trying to identify?
If it is a DC brushed motor, then one would have continuity to ground, the other two being the motor supply.
If it is a DCBL then the three conductors would have the same continuity/resistance between any two, and be the 3 phase stator winding.
Al.

[Khaled.Hosam]

I know the motor connection wires, what I wanna know is the connection of the encoder itself

[Al_The_Man]

It cannot be a quadrature encoder as at least 4 conductors are required.
A resolver requires 6, unless it is a digital tach of some kind?

Can you post a photo of the encoder.
Pretty difficult to get a bi directional count with three wires, unless a serial encoder of some kind, even then it would be tricky!
Al.

[mike_Kilroy]

Ah, u say u bought a used DC motor..... so Al is prob right - prob is a TACH not an encoder at all. 2 wires plus a shield wire? tell us part no of motor so we can help. also ohm between all 3 wires and tell us what u get. from these 2 things we prob can help identify for u.