I recently bought some motors of ebay. They have opto couplers on them and they are a decent, see the picture.
How do I tell if they are stepper motors with encoders or servo motors with encoders?
They look like DC motors, not stepper nor servos.
how many wires do eahc have coming out of them?
2 of them look to have 3 wires and 3 look to have 4 wires. They don't look like any stepper motors I have ever seen, and, they really don't look like any servos I have seen either. I am more inclined to agree with amando96, and his DC motors comment.
I think that you can make a servo from a dc motor using a encoder? no?
Wires are 2 from motor 3 from encoder and 2 from motor 2 from encoder.
Can you use these types of motors for positional control then?
It's not a servo, sure, you can make one, but it's going to be difficult if not impossible(I don't know how much you know) it's simply a DC motor with an encoder, this is useful for locomotion on a robot, but you can't directly attach the wheels to motor, you'll need some form of gearing to bring down the speed and increase the torque.
I really doubt it's a stepper due to its shape and the openings in the metal. 99% sure it's a DC motor.
Yes I have had steppers in the past 1200oz down to 270oz, actually have some 270oz left. I just bought these on ebay cheap and have just starting buying heaps of electronic parts and a scope.
So how can I work out max voltage on these?
if those are dc motors, then WTF are the extra leads for???
Maybe it could be just a built in tacho?
See new pic