1. An inverter can be programmed to stop an AC motor quickly by enabling

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1 Student ID: Exam: Controlling Industrial Motors When you have completed your exam and reviewed your answers, click Submit Exam. Answers will not be recorded until you hit Submit Exam. If you need to exit before completing the exam, click Cancel Exam. Questions 1 to 25: Select the best answer to each question. Note that a question and its answers may be split across a page break, so be sure that you have seen the entire question and all the answers before choosing an answer. 1. An inverter can be programmed to stop an AC motor quickly by enabling A. a stationary AC waveform. B. DC voltage injection to the motor. C. an internal brake. D. a reverse pulse action. 2. If rods are used to support a precision movement such as a positioning table, the table will ride on the rods on A. a lead screw. B. gibs. C. brass alloy nuts. D. ball bushings. 3. A control system that doesn t return position or velocity information from the motor back to the control system is called a/an A. open-loop system. B. directional system. C. translated position system. D. differential system. 4. You re powering up a new motor in a brushless motor control system. After moving the shaft of the motor lightly left to right, the motor reverses direction and runs away. What s the problem? A. Reversed hall-effect sensor B. Power transistor failure C. Reversed tachometer D. Wrong motor type 5. The easiest place to install an ammeter into a stepper motor driver/motor circuit for system diagnostics is to A. connect the meter across the center tap and phase leads of the motor. B. remove a fuse and place the meter leads across the fuse clips. C. attach the meter in series with the driver s power supply lead. D. disconnect a motor lead and attach the meter in series with that lead.

2 6. A 200 step-per-rotation stepper motor is attached to a table with a five-pitch lead screw. How many turns of the motor are required to move the table two inches? A. 10 B. 5 C. 2 D A bipolar stepper motor has how many wire leads exiting from the motor? A. 4 B. 8 C. 2 D A type of feedback device that uses a rotor and senses the position of the motor by means of sine and cosine waveforms is called a/an A. encoder. B. tachometer. C. alternator. D. resolver. 9. You re looking at a tachometer feedback signal on an oscilloscope. The waveform takes a long time to go to zero volts. This means that the system is A. reversing direction. B. at high speed. C. critically dampened. D. overdampened. 10. The type of motor that s used with an older indexer controller is the A. DC servo motor. B. stepper motor. C. three-phase stepper motor. D. brushless motor. 11. If an open-loop stepper motor system is mispositioning, the first thing you should do is to A. replace the axis logic card. B. replace the motor. C. detune the ACCEL, DECEL, and MAX potentiometers. D. increase the motor s current. 12. In a DC servo motor system, the tachometer feeds back a voltage that s proportional to motor speed. Where does this voltage go to? A. The CPU in the main controller

3 B. The axis logic card C. The interpolator card D. The driver 13. The type of transistor configuration that s used with a DC servo motor is the A. negative-logic configuration. B. H-bridge configuration. C. totem pole configuration. D. emitter-follower configuration. 14. A scaling or header plug is used on some brushless motor drive systems to A. connect the front panel indicator lights to the drive. B. set the current limit of the drive. C. connect the tachometer to the drive. D. divide the output pulse train. 15. A type of lead screw that has squared-off threads is the A. Evans screw. B. Thomas screw. C. Cross screw. D. Acme screw. 16. The output terminals of most servo motor systems are marked with the letters A. C, D, and E. B. T, Q, and R. C. X, Y, and Z. D. U, V, and W. 17. An encoder is being used instead of a tachometer in a DC servo system. This system of speed control is called A. open-loop feedback. B. bit counting. C. dual-purpose feedback. D. dual-connection feedback. 18. What type of waveform uses a primary signal with no harmonics? A. Sawtooth B. Sine C. Triangle D. Square 19. The type of stepper motor that has a pair of center-tapped windings is the A. reactive stepper motor.

4 B. closed-loop stepper motor. C. unipolar stepper motor. D. center-biased stepper motor. 20. The S functions of an industrial controller are normally used to control the A. tooling selection. B. coolant pump and other motors. C. software delays. D. spindle speed. 21. The typical switching frequency of a brushless servo motor driver is A. 5 khz. B. 15 khz. C. 10 khz. D. 25 khz. 22. The type of sensors that are used on most simple brushless motors to identify motor rotor position are the A. optical-range sensors. B. capacitive sensor. C. field-effect sensors. D. hall-effect sensors. 23. The maximum number of lines of resolution of an encoder that s used with a three-phase stepper motor is A B. 15,000. C. 10,000. D. 20, What type of circuits are present on an axis logic card for a stepper motor system and are used to accelerate and decelerate a motor? A. Ramp circuits B. Bias circuits C. Main oscillator circuits D. Timing circuits 25. A servo system is oscillating at standstill. This is an indication that A. the system gain is too high. B. the following error limit has been exceeded. C. a driver fuse is blown. D. a motor winding is open.

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