How can I wire a bipolar stepper motor to switches for my laser engraver?

[Scottydntno]

TL;DR

Trying to wire a bipolar stepper motor to a switch(s)

Hello everyone,

I currently bought a Z axis table for my laser engraver. I am trying to hook the stepper motor up separately. I currently have a 12v transformer, a capacitor, 2 push button switches and one 3 way switch along with the stepper motor. Is there any way I can wire the stepper to the switches?

 

[berkeman]

Welcome to the PF.

Which stepper motor is it? Can you post the datasheet? Are you familiar with the drive waveforms for steppers, to step each direction and to hold position?

 

[Scottydntno]

Welcome to the PF.

Which stepper motor is it? Can you post the datasheet? Are you familiar with the drive waveforms for steppers, to step each direction and to hold position?

I bought the Z Table from Lightobjects.com they have been very "not" helpful with ANY information. I can get the motor to move in one direction but then I would need to manually switch the wires over. I would like to be able to driver the stepper motor in both directions via 1 switch for up and one switch for down.

 

[256bits]

Is this the circuit you made?
You don't mention a controller.

 

[Scottydntno]

Is this the circuit you made?
You don't mention a controller.
View attachment 254508

Is a controller the ONLY way to run a stepper motor?

 

[256bits]

Is a controller the ONLY way to run a stepper motor?

You had, or did not have, a controller when it ran in one direction.
Is that your circuit?

 

[berkeman]

Is a controller the ONLY way to run a stepper motor?

Are you familiar with the drive waveforms for steppers, to step each direction and to hold position?

You didn't answer my last question...

https://www.imagesco.com/stepper/waveform.jpg

 

[zoki85]

Is a controller the ONLY way to run a stepper motor?

Of course not. If demands of positioning and activation are simple enough one can make relay network instead of a controller to run it.

 

[arydberg]

Yes you must have a controller. a stepper requires on off pulses on each of 3 or perhaps 4 ciircuits. It can be done with logic circuits

 

[Scottydntno]

Thank you all for your advise, but I was successful at running the bipolar stepper motor with a 12v transformer, capacitor, and a 3 way momentary switch in both directions flawlessly.

 

[256bits]

Thank you all for your advise, but I was successful at running the bipolar stepper motor with a 12v transformer, capacitor, and a 3 way momentary switch in both directions flawlessly.

Yes. You were successful running it. That's good.
Choosing the right capacitor so that one coil is 90 degrees out of phase, or nearly, with the other coil does the trick. So now the motor runs somewhat like a regular motor, but IIR, not as efficiently.

But with the capacitor circuit, moving the table to a particular position is quite near impossible. The motor will run back or forth, but getting it to an exact position requires a keen eye and some luck, which when moving your table may not be satisfactorily reproducible each and every time.
Stopping and holding it at a particular position requires additional circuitry.
To count the number of rotations of a motor or shaft, have an external counter - ie magnetic pickup, photo diode,... One doesn't need a stepper motor. You could count the number of AC cycles, but the acceleration of the motor and ( changing) torque upon it, makes that problematic.

But you have a stepper and should make use of its features.
The thing about a stepper is that you can set the amount of rotation of the motor by energizing the coils in a certain way. See post #7. The motor "steps" into the next "degree" of rotation.
You need a counter to count the steps, either up or down from some zero position, some transistors( relays ) connected to each coil, and some logic circuitry to turn the transistors on and off in a particular fashion.
You can make your own circuitry, or a use package on a chip.
I have always like this page.
http://homepage.divms.uiowa.edu/~jones/step/circuits.html

 

[arydberg]

Thank you all for your advise, but I was successful at running the bipolar stepper motor with a 12v transformer, capacitor, and a 3 way momentary switch in both directions flawlessly.

Your 3 way switch is thed controller.