🔍 Key Concepts

• For a 3-phase induction motor, direction of rotation depends only on the phase sequence at the motor terminals, not on which physical terminal is called T1, T2, or T3. • Swapping any two phase leads (and only two) will reverse the phase sequence and therefore reverse rotation; a cyclic permutation of all three phases keeps the same rotation. • Carefully trace, for each diagram (A–D), which line (L1, L2, L3) ends up on each motor terminal (T1, T2, T3), then work out the effective phase order at the motor: is it still A‑B‑C, or has it become A‑C‑B (or equivalent).

💭 Think About

• For motor A, you are told it turns CW with an A-B-C phase sequence at T1-T2-T3. For each of B, C, and D, what is the phase order arriving at T1, T2, T3 when you follow the new wiring? • In each configuration, ask: have I simply renamed/rotated which terminal is called T1, T2, T3 while keeping the same A-B-C order, or have I actually reversed that order (A-C-B or its equivalent)? • Which of the figures show only two leads interchanged (true phase reversal) and which show a rotation of all three connections (no reversal)? Link that to CW vs CCW rotation.

✅ Before You Answer

• For each motor, explicitly write a small table: T1 = ?, T2 = ?, T3 = ? in terms of L1/L2/L3, then convert that to a phase sequence like A-B-C or A-C-B. • Verify which diagrams result in a cyclic shift of the sequence (e.g., B-C-A or C-A-B), which is the same rotation direction, and which result in a reversed sequence (e.g., B-A-C, C-B-A), which reverses rotation. • Before choosing an answer, double-check that you have not confused interchanging two leads (reversal) with permuting all three in order (no change in rotation).