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

Question 1 / 270705eccefa4bacbc34ba4d481fb

Question 1 of 270705eccefa4bacbc34ba4d481fb

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

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Question 1 of 27070

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

🔍 Key Concepts

• Synchronous speed of an AC induction motor and its formula • How the number of stator poles affects motor speed in a fixed-frequency system • Which motor characteristics are affected by rotor resistance vs. which control speed steps

💭 Think About

• In a fixed frequency system, which quantities in the synchronous speed formula can practically be changed during operation? • Which of the answer choices directly changes the number of magnetic poles seen by the rotating field? • Which options mainly affect starting characteristics (like starting torque or inrush current) rather than establishing distinct operating speeds?

✅ Before You Answer

• Recall the formula for synchronous speed and identify the variables that can change: frequency and number of poles • Check which choice specifically mentions a way to vary the number of stator poles (or pole groups) to obtain multiple discrete speeds • Eliminate options that refer to starting conditions (locked-rotor current, rotor resistance) rather than establishing different synchronous speeds in a fixed-frequency system

Question 1 of 27070

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

changing the number of phases to the motor

changing the number of stator poles

changing the locked rotor current

changing the resistance of the rotor winding

Question 1 / 270705eccefa4bacbc34ba4d481fb

Question 1 of 270705eccefa4bacbc34ba4d481fb

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

Back

Question 1 of 27070

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