Match functional blocks in a classical servo control system to representative hardware. List I (Functional component) List II (Device example) A. Error detector 1. Three-phase fractional-horsepower induction motor (FHP IM) B. Servo motor 2. Synchro transmitter and control transformer C. Amplifier 3. Tacho generator (feedback signal) D. Feedback element 4. Armature-controlled FHP DC motor 5. Amplidyne (power amplifier)

Introduction / Context:
Classical servo systems comprise an error detector, a power amplifier, a servo motor, and a feedback element. Recognizing typical hardware that implements each block is crucial in control systems and mechatronics.

Given Data / Assumptions:

• Error detector compares reference and feedback signals.
• Servo motor converts the amplified control signal into mechanical motion.
• Amplifier raises signal power to drive the motor.
• Feedback element measures speed or position to close the loop.

Concept / Approach:

Synchros (transmitter and control transformer) form a classic error detector by producing a voltage proportional to angular difference. An armature-controlled FHP DC motor is a canonical servo motor due to easy speed control. Amplidynes (rotating amplifiers) historically served as powerful control amplifiers. A tacho generator delivers a voltage proportional to speed for feedback.

Step-by-Step Solution:

Verification / Alternative check:

Control textbooks show synchro error detectors in position-control servos; DC servomotors are used for precise control; amplidynes provided high power gain before solid-state drives; tachogenerators remain common for speed feedback.

Why Other Options Are Wrong:

• Mapping the amplifier to an induction motor misunderstands block roles.
• Using a three-phase induction motor as the standard servo motor complicates control; DC servomotors are the classical choice for fine control.

Common Pitfalls:

Confusing sensors (tacho) with error detectors (synchros); the former measures speed directly, while the latter measures difference between commanded and actual positions.

Final Answer:

A-2, B-4, C-5, D-3