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ANSWERS TO QUESTIONS Q1. THROUGH Q25.

A1. A system in which the precise movement of a large load is controlled by a relatively weak control signal.
A2. Usually the operator senses the desired load movement and reduces the input to stop the motor.
A3. Feedback.
A4. Input signal and feedback.
A5. To move the load and provide feedback data to the error detector.
A6. Classifications in accordance with position, velocity, and acceleration functions.
A7. Amount and direction of rotation.
A8. Hunting.
A9. Velocity loop senses velocity rather than position. When velocity loop is nulled, an error signal is still present and the load continues to move.
A10. Tachometer.
A11. The closed-servo loop can regulate load speed under changing conditions.
A12. Underdamped.
A13. Overdamped.
A14. To minimize overshoot and/or oscillations.
A15. Anticipating.
A16. It should oscillate.
A17. Unwanted noise-generated frequencies are rejected.
A18. Zero.
A19. (a) Phase. (b) Amplitude.
A20. E-transformer and control transformers.
A21. The method of primary excitation (ac and permanent magnet).
A22. To convert a dc error signal into an ac error signal.
A23. To convert an ac error signal into a dc error signal.
A24. To switch control of the amplifier between either the coarse signal and the fine error signal.
A25. Two saturable reactors and a transformer.