🔍 Key Concepts

• Rotor slip and how it relates to different AC motor types • Difference between induction motors and synchronous motors • Which motor type can run at exact synchronous speed with the rotating magnetic field

💭 Think About

• For each choice, ask: does this motor inherently require slip between the stator field and the rotor to produce torque? • Consider which motors are commonly used where constant speed exactly locked to line frequency is important. • Think about which motor types are called synchronous versus induction and what that implies about rotor speed.

✅ Before You Answer

• Verify which motor types are induction motors and remember that induction usually implies non-zero slip under load. • Check which option describes a motor whose rotor speed is locked to the stator rotating field speed (no slip in steady-state). • Eliminate any motor types that are designed to operate on both AC and DC if the question is specifically about an AC propulsion drive emphasizing no rotor slip.