Machine types – What does “squirrel-cage” describe? Statement: “The term squirrel-cage applies to a type of three-phase AC generator.” Choose the best answer.

Electrical Engineering Three-Phase Systems in Power Applications Difficulty: Easy
Choose an option
  • A
    True
  • B
    False
  • C
    True only for permanent-magnet alternators
  • D
    True for single-phase machines only

Answer

Correct Answer: False

Explanation

Introduction / Context:Machine nomenclature can be confusing across motors and generators. “Squirrel-cage” is a widely used term in industry and examinations. Correctly identifying where it applies helps avoid misinterpretations in specifications and maintenance manuals.

Given Data / Assumptions:

  • Standard AC machines: induction motors, synchronous machines, and alternators.
  • “Squirrel-cage” refers to a specific rotor construction.
  • Focus on whether it describes a generator type.

Concept / Approach:

“Squirrel-cage” describes the rotor of an induction motor: aluminum or copper bars shorted at both ends by end rings, resembling a cage. It is not a descriptor for alternators (AC generators). Alternators typically have a wound or permanent-magnet rotor and a three-phase stator; the term “squirrel-cage generator” is not standard terminology.

Step-by-Step Solution:

Identify that induction machines are predominantly motors with cage rotors.Alternators (synchronous generators) use DC-excited or PM rotors, not cage rotors as a classification.Therefore, the statement is false.

Verification / Alternative check:

Catalogs and datasheets label “squirrel-cage induction motors,” while generators are labeled “alternators” or “synchronous generators,” confirming standard usage.

Why Other Options Are Wrong:

Qualifiers about permanent magnets or single-phase do not transform the term into a generator descriptor.

Common Pitfalls:

Assuming any rotating electrical machine could be termed “squirrel-cage.” Keep the association strictly with induction motor rotor construction.

Final Answer:

False.

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