I'm looking for help on stepper motor and driver builds and setup. I currently have a useable set up that is functional but not perfect. Anyone willing to help a newbie that is eager to learn?

 

More info on what you have, and what you are trying to achieve.??

 

Certainly there is help available, but the request for help tells us nothing about what is actually needed. AND I am unable to read minds and se what somebody actually requires.
An adequate description of what the TS already has, how it functions, and what functioning is wanted to be added will be a fair start. There is a whole lot of stepper motor system design available, but mostly not on this site.

 

Certainly there is help available, but the request for help tells us nothing about what is actually needed. AND I am unable to read minds and se what somebody actually requires.
An adequate description of what the TS already has, how it functions, and what functioning is wanted to be added will be a fair start. There is a whole lot of stepper motor system design available, but mostly not on this site.

Thank you for your reply. Sorry I didn’t explain myself further. I will attach a couple of pics of my device. I have a engine break in machine for radio controlled airplane engine that I have made. The machine functions with the stepper connected but if I try to reverse the direction of the stepper it will reverse but the stepper then starts making a “grinding” type noise like it is not wired correctly. Also on my machine I’m trying to figure out how to read the RPMs the stepper is spinning as well as the load against it.

 

Engine break (Engine brake??)
That is a fairly large and heavy motor for a typical RC aeronautical application!?
Still now sure of the application?

 

Engine break (Engine brake??)
That is a fairly large and heavy motor for a typical RC aeronautical application!?
Still now sure of the application?

No not a engine brake. A engine break in machine. It is used to cycle the engine in a oil bath. The engine has a very tight "Pinch" at top dead center. That is why the stepper is that large. The application is to break in a radio controlled engine.
Step 1: heat the engine to operating temp in a oil bath.(different device than this one)
Step 2: cycle the engine in the oil bath with the stepper motor at a lower RPM as it wears the RPM increases.
Usually takes about 4-6 hours to break the engine correctly.

 

Wouldn't it be simpler to run the engine itself at high rev's to break it in?
My only experience with RC engines goes back to the 60's and these were compression ignition!

 

Wouldn't it be simpler to run the engine itself at high rev's to break it in?
My only experience with RC engines goes back to the 60's and these were compression ignition!

Yes that would be simpler and that has been the standard for a long time. I have found by doing the oil bath with a stepper driving the engine I have increased performance with additional durability. Also it takes away the mistakes that can be made during the standard method. Trust me I wouldn't be investing the time and money to build something like this if I felt the standard method was as good or close to this method. I'm involved with this at a very high level, not flying around the local airfield. I have competed in 11 countries doing this. So I'm looking for the extra 1%. Thank you for showing a interest in what I'm building. I haven't found a lot of help with this and I also haven't been able to find much in the way of training material.

 

How does the stepper motor run in both directions when it is not loaded ? That can provide some information about the problem
And from the picture it looks like a four wire stepper motor It might be that there is a failure in the driver circuit.

 

Here

How does the stepper motor run in both directions when it is not loaded ? That can provide some information about the problem
And from the picture it looks like a four wire stepper motor It might be that there is a failure in the driver circuit.

Funny you mention that. In one direction it runs nice and smooth through the RPM range of the motor. In the other direction it starts off ok all though it does make a odd sound half way through the rotation. As you increase the speed in that direction it gets worse until the stepper motor locks and stops.

 

Here is a picture.

 

Sorry it didn’t attach the first time.

 

Or the second. Lol sorry

 

OK, and the connections seem to be simple enough. The first thing to check requires a reasonably accurate ohms meter. That would be to verify that the motor windings are actually wired as they should be.
You may have done this already, but I am starting at the beginning.
A stepper motor might run with some wrong connections, but not as well. You also need to verify that the resistance of the two windings are close to the same. The correct connections are shown on the panel by the terminals.

It might also be that the pulses per revolution setting is not optimum. There might even be a problem with that connector in the one half of the motor connection.
And one other thing would be to check the driver supply voltage to see if it drops when the opposite direction is selected.

 

Just my opinion but that would seem to be a better machine using a regular DC motor or DC gear motor. Steppers are best when used as the name says, steps, not constant RPM. Any type of resistance to turning that is done with a stepper can also be done with a DC motor, something that is made to revolve smoothly not make steps.

 

Given that the existing mechanism works well it makes sense to try to solve the problem with this setup. A variable speed motor quite a bit different from a stepper, as far as torque and smoothness of rotation. And breaking in a high compression motor is far from a common application.
The condition of running well in one direction but not the other direction is very puzzling for a stepper.
So I am quite interested in solving this problem, for my education as well.

 

It runs great in one direction as I said before. Is it possible I'm not driving it with enough voltage? My power supply is 12.5 volts with 50 amps. It doesn't make sense to me why that would make it run great in one direction and not the other. I was thinking of getting a different power supply. Suggestions are welcome. I was also considering getting a new driver with more capabilities. I'm looking to be able to monitor the load on the stepper motor and the rpms the stepper is spinning. I might get super out there and connect Arduino to it so I can make a program for the break in cycle, but that maybe getting out there a bit. Any ideas on any of this I'm all ears. I checked the connections and also made sure the A+, A-,B+,B- were wired correctly. I verified all the exiting wiring to the power supply, driver and potentiometer. I check the dip switched and jumpers. All seems good. I did not check the resistance of each winding yet as my good voltmeter is at work. I will tomorrow

 

OK, and after examining the picture once again, and reading about the power supply being used, I see that the specified input voltage range is +20 volts to +50 volts, while the reported power supply is 12 volts.
So my suggestion now is based on the fact that the supply voltage is outside the claimed operation range, which operation may not be within the claimed performance range. So I suggest trying the system with a voltage within the limits, such as 24 volts DC, and see how it works there. My guess is that the performance will be satisfactory.

 

I purchased a 48 volt 20 amp power supply. It should be here Thursday so I will get it set up on Friday night. Any suggestion on the rpm or load meters while I'm waiting for that to get here?

 

To read RPM on a stepper drive will take a frequency counter that can be scaled to the correct number of pulses per revolution. Red Lion brand is one that I have used, and they were able to recommend a product based on the requirements. That will give you an exact RPM measurement.
Reading torque is more complex, especially because a stepper motor steps, and does not turn smoothly, at least not at lower speeds. A mechanical torque measurement would be the simple scheme, and it will be the simplest to calibrate accurately.

The setup would require supporting the stepper motor by the shaft, and a bearing on the same axis at the opposite end, so that the motor housing would be free to rotate about the shaft's axis. The the force required to hold the motor housing from rotating multiplied by the length of the lever arm tied to that force, is the actual torque delivered. I have used this exact scheme with a load cell to read torque and it works very well, and it can be calibrated very accurately using weights and an accurate measurement of the torque arm.
The accuracy of the calibration is limited by the accuracy of your weights and distance measurement, the resolution is limited by the linearity and resolution of your display. So it is easy to be well withing 1% of the reading.