Is my 17HS4401 faulty?

Hello,

I have ordered 3 NEMA 17 stepper motors (17HS4401 to be more specific). I am using big easy drivers to drive the motors.

I have created a program that turns the motor precisely one revolution, then back one revolution, and so on. I am doing 3200 steps because I am using sixteenth steps.

For 2 of my motors it works perfectly. However, for one other motor it does just less than one revolution (perhaps 80% of a revolution). It seems like steps are being skipped.

I am wondering whether or not I am doing something wrong or if there is something faulty with the third motor. If it is the latter, which I am fearing for, is there anything I can do to fix the motor?

My code is attached below. My wiring is exactly like this: http://bildr.org/blog/wp-content/uploads/2012/11/big-easy-driver-arduino-2.png

Thanks in advance,

JosDes

_17HS4401_test.ino (567 Bytes)

Please post a link to the datasheet for your stepper motors.
Are you certain they are all identical?
Don't rely on wire colours to identify the coil connections. Check with your multimeter.

Also give details of your motor power supply (volts and amps).

Are you testing the motors one at a time?

...R
Stepper Motor Basics
Simple Stepper Code

I have attached the data sheet below, look for 17HS4401 model in the list. I am sure they are all identical.

I have double checked the coil connections with my multimeter and they are correct.

I am using a variable power supply, which can supply up to 2 amps. I currently have it set at 12v. My other motors work fine at this setting.

I am testing the motors one at a time yes.

Thank for replying so soon!

17HS4401-MotionKing.pdf (94.9 KB)

That motor should work OK with a BigEasydriver although at 1.7amps it may be overstressing it a bit. I am assuming you are NOT confusing an Easydriver and a BigEasydriver.

Are you trying the three motors one at a time with the same driver, or have you a separate driver for each motor?

If the latter, try swapping the doubtful motor to a different driver. And are you sure each driver is set for the same level of microstepping?

I would also try the motors with single stepping.

If you are using the same driver for all the tests it does throw suspicion on your motor. But if all the coil resistances are the same for all the motors (and the same as the datasheet) I can't immediately think what could be causing the problem.

I presume, when the motors are disconnected from power, that they are all equally easy to rotate with your fingers - i.e. none has unusually high friction.

I appreciate this is not much help.

...R

Okay thanks for that. I will try all that you have suggested.

I will post an update if more information comes to light.

I'm an idiot. I figured out what the problem was.

I was using a bit of tape attached to the shaft of the motor to easily see the rotation. For this third motor I was using a rather large piece of tape. The sudden acceleration of the motor caused the large bit of tape to move, which made it seem like the motor was not completing a full rotation. In fact it had been successfully completing rotations since the beginning...

JosDes:
I'm an idiot. I figured out what the problem was.

Welcome to the club :slight_smile:

...R