Stepper Motors A typical stepper motor has four coils evenly spaced around the field and a permanent magnet armature. If any combination of field orientation can be generated by controlling which coils are turned on, and which direction current flows through each coil, how many different steps or positions can the motor have per revolution? Considering that the motor has 4 different positions of which will discuss them in order to determine the number of the different steps or rather positions that the motor has in one revolution.
The illustration of the 4 frames is shown below where the electromagnets are the 4 inner blocks with 4 teeth each. The electromagnets are numbered, electromagnet 1(one labeled 1 and is blue). The next electromagnet is electromagnet 2 which is next to electromagnet 1 in the clockwise direction. Then, have electromagnet 3 and electromagnet 4 in the same clockwise direction. Fig 1. Figure shows the step motor In position 1, the electromagnet 1 which is on top is turned on; it attracts the teeth on the iron rotor gear (red in color).
In this way, the gear teeth are aligned to the electromagnet 1. In position 2, electromagnet 1 is maintained as on while electromagnet 2 is powered making the 2 to be on. This aligns the gear teeth between electromagnet 1and electromagnet 2 resulting to a 45 degrees rotation. In position 3, electromagnet 1 is powered off; this will result to alignment of rotor with the electromagnet 2. This leads to an addition rotation of 45 degrees. The moment electromagnet 1 on top is powered again; the rotor will have undergone 8 steps comprising each of 45 degrees.
This is due to the fact, the rotor has to go complete revolution which is 360 degrees; it will thus cover (360/45) = 8 steps to make a complete rotation. For the stepper motor shown in problem 3, draw a pulse train for the four coils that will rotate the motor in eight 45 degree steps all the way around the motor. For each step covered by the coil that translates to one pulse so since the coil undergoes 8 steps the pulse train will contain 8 pulses as shown in the diagram below. Fig 2.
Shows the 8 pulses of a pulse train for the 4 coilsWork cited1. “Integrating PC- based logic and motion control” White paper, Entivity I Incorporation2. Benjamin C, Kuo. “Incremental motion control-step motors and control systems”, 19793. Technical paper “Introduction to stepper motor system”. Anaheim Automation Corporation4. Douglas W. Jones “Control of stepping motor. Tutorial” http: //www. cs. uiowa. edu/~jones/step? types. html5. http: //www. sdp-si. com/D220/PDF/D220T155.pdf6. Susan Weinscheck, Pamela Jamar, Sarah C. Yeo. “GUI design essentials”. 19977. Randolph J. Andrews.
“Motion control terminal blocks: the next step in distributed motion control”, Incremental Motion Control Systems and Devices Symposium, 19998. Parker Hannifin Corporation technical paper. “Linear motor basics”9. www. Compumotor. com. Retrieved on 19th March 2013.10. www. motorola. com. Retrieved on 19th March 2013.