Hello, I recently purchased a RB-Soy-14 stepping motor and I am unable to make it run, whether I connect the centre taps to power and the coils to transistors to ground or the centre taps to ground with the coils going to another set of transistors to power, both situations, I am using a EDE1200 to a ULN2803 to run the transistors. I am assuming from the spec. sheet that the Black, Yellow(centre tap) and Green is one coil pair and the Red, White(centre tap) and Blue is the other coil pair?. Is there some way of testing the motor by itself? and if so how do I accomplish this?. KN
Hi,
Your assumption of the wiring of the motor’s coil seems to be in agreement with the manufacturer’s datasheet:
For your wiring of the driver chip and Darlington pair transistor chip, we recommend that you look at this wiring diagram and see if your setup matches up to it:
We also recommend that you read thoroughly the datasheets for these components to ensure you are using them properly. If in doubt, try to contact the manufacturer (or the supplier you obtained them for) for more details.
For your specific setup, please include one or more pictures clearly showing your current setup so we can offer more advice/ideas/solution.
Sincerely,
I am sending my schematics and it does not matter which way I hookup, the motor does not operate, I do not think my circuit is at fault, but I do think that the motor is the problem, would be nice to know how to check the motor on it`s own.
PS: I just tried to add my schematics, a pop up wants an URL, I do not know what this is, so your web site will not let my add them.
Hi,
You can add attachments by from the Full Editor options. The attachment option is above the orange buttons (Preview, Submit, Save draft, Cancel). Please see the attached image for details.
Sincerely,
I am sending my schematics and it does not matter which way I hookup, the motor does not operate, I do not think my circuit is at fault, but I do think that the motor is the problem, would be nice to know how to check the motor on it`s own.
Hi,
Your schematic seems right. Assuming your switches are set properly, that your 555 is providing a proper clock for the STEP input and your outputs drive the right motor coils, it seems like it should work. Did you check with a multimeter the outputs at the final stage (the connections that go to the motor leads / coils)? You could verify two things:
]Check if the voltage changes as expected (at each step). You may want to lower the 555’s speed to very slow so you can check this more easily./:m]
]You can also place the multimeter in series and check the current drawn. As each coil energizes you should be able to see a current similar to the rated current for this motor./:m]What type of power supply are you using? Can it provide enough current for your application?
In the case that all of your setup is good and providing the right voltage / current at each coil, the simplest test of your stepper motor would be to check the coils one by one. First, you can use a multimeter to measure the resistance between each coil end and the common wire. Each of those should have the same resistance. If one is significantly higher or lower (or even shows as a short), then you may have damage on one of the coils.
If all the coil’s resistance seem fine, then you can apply power to each of them one at a time (VCC > coil wire, GND > common wire). This will energize a coil and lock the stepper motor in place. You can check if there is holding torque by trying to turn the motor’s output shaft before and after energizing the motor. There should be little or no resistance before and much resistance after the coil is energized.
Sincerely,
Ok, I did some measurements, I am using an RV deep cycle battery so lots of juice. The rail reads 12.22 v - drops to 11.6v at each transistor as each turns on. Draws .65A at each transistor as it turns on. I cannot turn the motor shaft by hand. The resistance of the coils are as follows: Black to Green of one pair of coils is 34.2 ohms, Black to tap Yellow is 17.3 ohms, Green to tap Yellow is 16.9 ohms, on the second pair of coils, Red to Blue is 33.6 ohms, Red to tap White is 16.7 ohms, Blue to tap White is 16.8 ohms.
What confuses me is when I apply power to the motor only, on each coil, the shaft moves slightly back and forth ex: Yellow centre tap to ground, plus to Black, shaft turns CCW but when put plus to Green turns back CW, again second coil, White centre tap to ground, plus to Red, shaft turns CW but when put plus to Blue turns back CCW, when I reverse the polarities the reverse happens, so to my way of thinking that no wonder the motor is not working, it is just going back and forth 1.8 degrees. If you would kind enough to clear this up for me, I would greatly appreciate it. Thanks
So, any thoughts on what the problem with the stepper, why it just goes back and forth?, or do I need to replace the motor?. Thanks
Hi,
If you believe you have a defective product purchased from us, please open a support ticket here. In your message, make sure to include your order or invoice number and a link to this thread.
Sincerely,
After viewing hundreds of web sites, I have been able to solve my problem with the stepper going back and forth, it now runs correctly in either direction as driven, I am sorry to say that I got no help from this site.