🔍 Key Concepts

• Synchronous speed of an AC induction motor and what determines it • Relationship between number of poles, system frequency, and motor speed • Which changes are possible in a motor connected to a fixed-frequency power system

💭 Think About

• First, recall the formula for synchronous speed and identify which variables you can change in a fixed-frequency system • Look at each choice and ask: does this change frequency or the effective number of poles seen by the stator? • Consider what happens physically to the rotating magnetic field when you change connections of the stator windings

✅ Before You Answer

• Verify which option actually changes the number of stator poles without changing supply frequency • Check which options would NOT affect synchronous speed in a fixed-frequency system (for example, changing phase sequence) • Confirm that rotor RPM in an induction motor is closely tied to the stator’s rotating field and cannot be set independently in a fixed-frequency system