Problems
1. T/F The difference between the two classifications of PM motors is whether the rotor and field are made of permanent magnets or coils.
2. The speed of a wound armature PM motor is varied by changing the current applied to the ______.
a. armature b. stator
3. List three applications of a wound armature PM motor.
4. The speed at which a moving coil motor runs is controlled by varying the ______.
a. amplitude of the DC voltage applied to the armature
b. width of the pulses applied to the armature
5. List two applications of MCM motors.
6. T/F BDCM motors usually use three-phase power.
7. The direction a BDCM motor turns can be reversed by switching two of the three connections to the ______ of the transistor.
a. base b. collector
8. The amount of force required to move the rotor of the BDCM motor away from the held position is called ______.
9. A ______ motor converts electronic digital signals into fixed increments of positional movement.
10. T/F The operation of a variable reluctance motor is based on the ease with which flux lines pass through soft iron.
11. If the stator's magnetic field of the VR stepper motor moves clockwise, the rotor turns ______.
a. clockwise b. counterclockwise
12. The stepper motor is typically used in a/n ______ (open, closed) -loop system.
13. A stepper motor that operates at a step angle of 12 degrees will rotate at what RPM if it has a stepping rate of 360? ______
14. In a variable reluctance motor, if the salient poles are 15 degrees apart and the rotor poles are 20 degrees apart, the step angle is ______ degrees.
a. 5 c. 20
b. 15 d. 35
15. The maximum number of steps a stepper motor can make in a second is called ______ ______.
16. The number of degrees a stepper motor turns per step is called ______ ______.
17. The speed at which a stepper motor turns is increased by ______ applied to the stator.
a. increasing the stepper rate applied to the stator
b. increasing the voltage
c. both a and b
18. A stepper motor with twice the step angle of a second stepper motor will turn at ______ the rpm if the stepper rate applied to both is the same.
a. half b. twice
19. Microstepping is achieved by ______.
a. gradually increasing the voltage applied to one coil while decreasing the voltage at a second coil.
b. simultaneously applying simulated sine waves that are out of phase to different coils
c. both a and b
20. In an AC servo motor, the phase-shifted voltage is supplied to the ______ winding.
a. main b. auxiliary
21. The speed of an AC servo motor is changed by varying the voltage applied to ______.
a. the main winding c. none of the above
b. the auxiliary winding