[Ettore]

I've probably wired this incorrectly, but yet to understand how. I have added a 4th axis to my Hobbycnc pro board, for an extruder to convert to 3d printing. My DROs and hot keys work but the motor does not turn, it gets too hot to touch and I am uncertain how to diagnose the problem. The motor is a Sanyo 2 phase stepper 103H5208-10U41 nema 17. Thanks, Pico

[doorknob]

What current setting did you use for the motor? It looks like the datasheet calls for 1.2 amps (for unipolar hookup).

Have you rechecked the wiring to make sure that you have identified the center tap wires correctly?

Can you verify that your Mach3(?) configuration is correct for the axis (for example, by checking the Direction signal voltage when you jog the axis in different directions)?

[Ettore]

I have rewired the 4th axis motor to the Z axis terminals, in what I think is correct order but not certain, plus in several other different configurations. The motor gets warm and hums but I get no movement. What way is there of checking if the motor is good? Doorknob - According to the Hobbycnc instructions, the voltage must be set to achieve the correct amperage. At first I set the voltage at .29 VDC, which was too much, the motor got too hot. I've reduced it to .1 which should be a little under 1A. Center tap wires - do you mean the common wire? They should be the white and black wires but don't know how to check them. Here is an image of the motor writing. From it I can only assume which is the A, a, B and b leads. The common leads are the black and white ones. I've tried numerous different combinations with no success. Thanks, Pico

[doorknob]

With a reputable manufacturer such as Sanyo, it is probably OK to trust that the color coding of the wires matches the color coding shown on the datasheet.

If you wanted to verify it, you could use a digital multimeter set to measure very low values of resistance (for example, on the 2 ohm full scale range), and with the motor leads completely disconnected from the driver circuit, measure the resistance between each pair of wires - the resistance from either end wire to the center tap 'common' wire should be less than the resistance across the end wires.

But the motor getting warm when hooked up (and hotter when too much current was being sent through the windings) could be a good sign that you wired the motors correctly and that the driver is sending current through the windings. But your statement of "plus in several other different configurations" is a little troublesome, because it's probably not a good idea to miswire the motor leads. Also, be careful not to disconnect any of the motor leads while your driver board is powered up, because doing so could burn out your driver.

So, maybe the problem lies elsewhere, which is why I suggested probing the direction signal to see whether the Mach3 pin settings were correct. But since you swapped a working Z axis hookup for the new motor, it is likely that you have ruled out the Mach3 pin settings.

So I'm a bit unsure of what to suggest next. Perhaps trying some temporary changes to the Z axis setup (for example, trying single stepping instead of microstepping) and putting some kind of load on the motor instead of just turning an unconnected shaft might get the motor to start turning.

[Ettore]

I will measure across the leads. I have been turning the controller off when working on it. I'm positive the Mach3 pin settings are correct. Actually the motor has been under load, I have it connected to the extruder and have manually turned it when attempting to jog it. How do I single step it? I am not clear which wires are the A,a, B,and b leads. Thanks for the advice, Pico

[doorknob]

How do I single step it? I am not clear which wires are the A,a, B,and b leads. Thanks for the advice, Pico

I don't have a HobbyCNC board, but from looking at their web site it appears that they use the term "1/1 microstepping" to signify 'full stepping' or 'single stepping'. So I would imagine that there would be a DIP switch setting on the board for that. Then every time you click the jog button you should be taking full steps of the motor.

As for A, a, B and b leads, your motor has two windings and each winding has three leads (two 'end' leads and a center tap). So, you can just arbitrarily call one of the windings your 'A' winding and the other winding your 'B' winding, and then hook up the two end wires from the A winding, one to A and the other to a (it does not matter which is which), then do the same for the B winding wires to connect to the B and b terminals. The center tap wires from both windings typically would go to the same point.

[Ettore]

Here's results from measuring the resistance: 5.7 between orange and blue end leads, 3.7 between blue end and white common, and 4.7 between orange end and white common. Also: 4.3 between yellow and red ends, with 1.3 between yellow end and black common, and 3.7 between red end and black common. I didn't know that the A and a , and B and b was arbitrary. When I press the job button, the DRO will run an inch or two. Is this what you by single steps? As apposed to a microstep? Please pardon my ignorance. Thanks, Pico

[doorknob]

The resistances that you measured are probably fine and it appears that the color coding of the wires is as described in the data sheet for the motor.

The amount that the DRO advances on the screen is based on the definitions that you have provided to Mach3 (for parameters based on the number of turns per inch of your leadscrew, number of steps per revolution of your motor, and microstepping factor). So Mach3 does not really "know" what your motors are doing, rather it only knows that it is sending step signals and that you have told it how many step signals are equivalent to a distance moved.

What I mean by single steps is that one step pulse sent from Mach3 results in the motor turning one physical step (which is the equivalent of turning 1.8 degrees).

At this point it may be helpful for you to seek help from someone nearby who has a background in CNC electronics (and who maybe has an oscilloscope).

[Ettore]

Is it possible that the driver and motor are not compatible? The motor spec sheet recommends drivers BSD-01P, BSD-13G, BSD-02, and BSD 02LH. Would this mean that these are the only drivers that should be used? My driver is a SK Japan SLA 7078MR 1303 P. Thanks, Pico

[doorknob]

That is extremely unlikely.

The datasheet for the motor shows that it is a conventional NEMA 17 stepper motor, which should be capable of working with your driver.

[Ettore]

Ok, thanks, one less thing to worry about. Pico

[Ettore]

Definiately an A motor problem. I wired the Z motor into the A terminal and got some humming, turned up the Vref and got movement. Onward into the fog..... Thanks for the advice. Pico

[doorknob]

OK, good luck with it...