Definition check – Polyphase systems Statement: “Polyphase is characterized by two or more sinusoidal voltages, each having a different phase angle.” Is this definition accurate?

Introduction / Context:
Polyphase systems underpin modern power transmission and many rotating machines. A clear definition helps discriminate single-phase, two-phase, three-phase, and multiphase systems used in power and signal-processing contexts.

Given Data / Assumptions:

• Sinusoidal voltages of the same frequency but with phase displacement.
• Amplitudes may be equal (balanced) or unequal (unbalanced).
• Two or more phases qualify as polyphase.

Concept / Approach:

Polyphase literally means “many phases.” Any system with two or more sinusoids of the same frequency that are phase-shifted relative to each other satisfies the definition. Common examples include two-phase (90°) and three-phase (120°) systems. Balance is desirable but not required by definition.

Step-by-Step Solution:

Verification / Alternative check:

Practical grids predominantly use three-phase due to constant power transfer and machine efficiency, but vector-control drives often synthesize multiphase sets (e.g., two-phase for control axes) that are still polyphase.

Why Other Options Are Wrong:

Requiring three phases only is too restrictive. Amplitude equality is not part of the definition; it pertains to “balanced” operation, not to being polyphase.

Common Pitfalls:

Confusing “polyphase” with “three-phase only,” or assuming unequal magnitudes disqualify a system from being polyphase.

Final Answer:

True.