Question

Which of the following pair of electro-mechanical devices are part of Synchro?

• A. AC tacho generator and Transmitter
• B. Transmitter and Control transformer
• C. DC tacho generator and Receiver
• D. Resolver and AC generator

Hint:

Remember that synchros always work in pairs to transfer angular data across distances. The most common pairs used for control operations are the Synchro Transmitter and the Synchro Control Transformer.

Answer 1

The Correct Option is B

Concept: A Synchro is an electromagnetic transducer used to convert the angular position of a shaft into an electromagnetic error signal, or vice-versa. It operates essentially as a variable transformer. A complete synchro system system loop typically comprises:
• Synchro Transmitter (Generator): Converts an input mechanical shaft angle into a set of three-phase electrical voltages.
• Synchro Control Transformer (or Receiver): Accepts these electrical outputs and acts upon them to reproduce the position or generate an error voltage proportional to the angular mismatch.

Step 1: Analyze the functions of Synchro components. A standard synchro error detector set consists of a Synchro Transmitter coupled directly to a Synchro Control Transformer. The transmitter contains a single-phase rotor winding energized by an AC source, inducing voltages into three stator windings spaced \(120^\circ\) apart. These stator leads are joined directly to the stator coils of the control transformer.

Step 2: Evaluate the options provided.
• Option (A) contains an AC tachogenerator, which is primarily a speed-sensing instrument, not an inherent element of a standard synchro pair.
• Option (B) explicitly matches the dual operational configuration used across position control loops (Transmitter and Control Transformer).
• Options (C) and (D) incorporate secondary elements or independent machines like DC generators or separate tachometers. Therefore, the correct choice is Option (B).