6 wire stepper motor - only need 4 wires to run?
guy20sanjose
Posts: 13
Hello
I'm using a BS2e module, a Board of Education Development Board - Serial Version, and a 6 wire- 9.5 V stepper motor. The weird thing is I only connect the 4 phases only, without the 2 RED wires connected (Power wires) the motor still running. My question is do I need to connect all 6 wires? And does the torque of the motor decrease because of the RED wires not connected?
Here is the diagram I connect for the 4 phases:
' P4 -> ULN2003.1, ULN2003.16 -> Phase 1 (Black)
' P5 -> ULN2003.2, ULN2003.15 -> Phase 2 (Orange)
' P6 -> ULN2003.3, ULN2003.14 -> Phase 3 (Brown)
' P7 -> ULN2003.4, ULN2003.13 -> Phase 4 (Yellow)
Any help is appreciated. Thanks in advance
I'm using a BS2e module, a Board of Education Development Board - Serial Version, and a 6 wire- 9.5 V stepper motor. The weird thing is I only connect the 4 phases only, without the 2 RED wires connected (Power wires) the motor still running. My question is do I need to connect all 6 wires? And does the torque of the motor decrease because of the RED wires not connected?
Here is the diagram I connect for the 4 phases:
' P4 -> ULN2003.1, ULN2003.16 -> Phase 1 (Black)
' P5 -> ULN2003.2, ULN2003.15 -> Phase 2 (Orange)
' P6 -> ULN2003.3, ULN2003.14 -> Phase 3 (Brown)
' P7 -> ULN2003.4, ULN2003.13 -> Phase 4 (Yellow)
Any help is appreciated. Thanks in advance
Comments
Now, there's something about your explanation that just doesn't make sense. The ULN2003 is an open-collector driver. It does not have any current-sourcing capability. Given your description, the motor should not run at all, since it's not being sourced with current. Are you sure you've provided an accurate description? Can you provide a full schematic?
Short answer: yes, the red wires need to be connected to a positive supply.
-Phil
Like I said, only 4 phases are connected. As soon as I power up the Parallax board, the stepper motor run. Please prefer to the picture.
Thanks
You did not describe your circuit accurately in the first post. The photo does not show a ULN2003, and the motor leads are connected directly to the BASIC Stamp. That changes everything, because the Stamp is sourcing current to the motor directly. That is a poor way to drive a stepper, because the coils are being energized in series, and you're effectively driving a 19V motor with 5V. I would recommend using the ULN2003 and connecting the red wires to a proper motor supply voltage.
-Phil