three wire encoder ... ??????

[shahidmk]

I bought some toshiba DC motors that have an optical encoder attached. My problem is that the encoder has only three wire connections coming out of it with no color coding or marking on the connections.
Can anyone help..!

ta

MKS

[Al_The_Man]

Are you sure that is an encoder? Post a photo if possible for positive ID. It might be a two wire tach + shield.
Al

[shahidmk]

will put up a pic as soon as I can get my hands on a cam. btw the disk has 40 slots in it.


MKS

[Al_The_Man]

Then It could be a digital tach, maybe. Any ID on any transistor or solid state device?
Al

[vladdy]

If there are only three wires, chances are it's either
black/ground, red or blue/power, green or yellow/pulse back..
it's 'probably' a tach drive, most three wire are..or
it may be a low reselution encoder without direction support, not very common on industrial stuff, but used on things like older large printers and copiers..
A tach drive will usually have additional circuitry to shape the wave form back into a proper square pulse, while an encoder application on a printer /copier motor this would be handled on the main board..

[shahidmk]

it does look as if it is a digital tach and not an encoder, my mistake. I wanted to use this to mount on my DC spindle to get the rpm on my home made cnc spindle. But the problem remains of identifying the connections as there are no markings and I am not aware of any methods of finding out the connections..

MKS
__________________________________
"There is pleasure sure in being mad which none but a madman knows to enjoy"

[Al_The_Man]

It is odd that it does not have colour ID on the wires, the easiest way is if you can see any solid state device, I would guess at minimum it would have a opto output transister, probabally open collector, or followed by a second discrete transistor for output, so obviously the termination would be 1 wire common, 1 Plus voltage, and 1 output,
The other scenario is that it is an opto-coupler and they bring all lead out without conditioning them (i.e, no series resistors etc), The led common and the transistor common would be connected internally allowing a three wire application.
The bottom line is to try and reverse engineer it.
Al

[ViperTX]

Do you have an ohmeter....make a matrix and record the values...it could just be an open collector output, with + - connections.