How is the speed of a multi-speed,...

Question 1 / 270705eccefa4bacbc34ba4d481f8

Question 1 of 270705eccefa4bacbc34ba4d481f8

How is the speed of a multi-speed, squirrel-cage, induction motor operating in a fixed frequency system changed?

Question 1 of 27070

How is the speed of a multi-speed, squirrel-cage, induction motor operating in a fixed frequency system changed?

🔍 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

Question 1 of 27070

How is the speed of a multi-speed, squirrel-cage, induction motor operating in a fixed frequency system changed?

reconnecting stator windings for different numbers of poles

changing the RPM of the rotor flux

changing the phase sequence of the applied voltage

reconnecting the stator so that no poles have the same polarity

Question 1 / 270705eccefa4bacbc34ba4d481f8

Question 1 of 270705eccefa4bacbc34ba4d481f8

How is the speed of a multi-speed, squirrel-cage, induction motor operating in a fixed frequency system changed?

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Question 1 of 27070

How is the speed of a multi-speed, squirrel-cage, induction motor operating in a fixed frequency system changed?