what *other* reasons can there be for a stepper motor to shake about randomly?

[dazzlepecs]

I am using a JSmotor-a driver board for a 103H546-0440 stepper motor.. I have gone over the wiring several hundred times to make sure its right, even so far as to go through the whole sequence of wire possibilities The documentation for the driver board shows what colours for this brand of motor as well.

Symptoms are:- When clocking the "clk A" (as per instructions) the motors just cruch around in a random order rather than turning in one direction... it does hold steady when not clocked so at least thats something

what else could be going wrong? The driver board is working fine as i have two and have swapped them in and out... I tried testing the activation sequence but im not sure how to do this...

 

[Leftyretro]

I am using a JSmotor-a driver board for a 103H546-0440 stepper motor.. I have gone over the wiring several hundred times to make sure its right, even so far as to go through the whole sequence of wire possibilities The documentation for the driver board shows what colours for this brand of motor as well.

Symptoms are:- When clocking the "clk A" (as per instructions) the motors just cruch around in a random order rather than turning in one direction... it does hold steady when not clocked so at least thats something

what else could be going wrong? The driver board is working fine as i have two and have swapped them in and out... I tried testing the activation sequence but im not sure how to do this...

Well one check you could make, if you haven't, is to measure the resistance of each of the windings to see if you have a open winding.

Lefty

 

[crutschow]

Is the clocking frequency within the normal operating range of the motor and load?

 

[picbits]

Don't rely on the colour codes of the motor to be correct.

If you have a phase back to front or you drive the motor in the wrong step sequence it will do what you are describing.

If its a bipolar motor, try swapping over a phase.

 

[dazzlepecs]

Well one check you could make, if you haven't, is to measure the resistance of each of the windings to see if you have a open winding.

Lefty

yeah thats a good idea, i checked that already though, its all in order AFAIK

Is the clocking frequency within the normal operating range of the motor and load?

it didnt specify actually, thats a good point.. I was clocking at maybe 1hz just to test

Don't rely on the colour codes of the motor to be correct.

If you have a phase back to front or you drive the motor in the wrong step sequence it will do what you are describing.

If its a bipolar motor, try swapping over a phase.

im not quite sure what swapping over a phase means ill have to research that.. Thanks for the idea!


edit- arg, seems to be a unipolar motor

 

[picbits]

Unipolar motors can be almost as easy to diagnose.

Measure the resistance from each phase and make sure you have the right wire for the common. Orange to white should give you the same resistance (give or take a bit of an ohm or so) as the white to blue wire. Same again with the red to black and yellow to black wires.

That only leaves you with 4 wires to incorrectly connect

You won't break anything by trying different combinations of those wires.

Something else you might want to try is to put an LED between each phase and ground or live depending on how you're driving the common and obviously with a current limiting resistor. That way you can watch which phase is activated and compare it with the step chart in the datasheet.

 

[dazzlepecs]

Unipolar motors can be almost as easy to diagnose.

Measure the resistance from each phase and make sure you have the right wire for the common. Orange to white should give you the same resistance (give or take a bit of an ohm or so) as the white to blue wire. Same again with the red to black and yellow to black wires.

That only leaves you with 4 wires to incorrectly connect

You won't break anything by trying different combinations of those wires.

Something else you might want to try is to put an LED between each phase and ground or live depending on how you're driving the common and obviously with a current limiting resistor. That way you can watch which phase is activated and compare it with the step chart in the datasheet.

ive gone through the possible combinations.. that was a pain in the arse!!!


Yeah watching the activation sequence is only thing left to do thanks

 

[Nigel Goodwin]

ive gone through the possible combinations.. that was a pain in the arse!!!

There's only four required, and four to rotate the other way.

 

[AlainB]

Hi,

One *other* reasons for a stepper motor to shake about randomly would be to have mistakenly swap the step (clk) and direction (dir) input sequences.

Once you are sure of the rotation sequence of the motor, in your case orange-red-blue-yellow, the black and white tied together to the positive side of the power source and since you know that the **broken link removed** is good, the problem could be at the input side: swaped step and dir wires or a software pin assignation problem.

As stated before, using LED really help to find out what is going on.

Alain