How is the speed of the propeller shaft...

How is the speed of the propeller shaft...

Question 1 of 270705eccefa4bacbc34ba4d4829d

How is the speed of the propeller shaft directly coupled to an AC synchronous propulsion motor changed when powered by a variable frequency alternator in an AC turboelectric drive system?

Question 1 of 27070

Q

How is the speed of the propeller shaft directly coupled to an AC synchronous propulsion motor changed when powered by a variable frequency alternator in an AC turboelectric drive system?

🔍 Key Concepts

• Relationship between AC motor speed, frequency, and number of poles • How a synchronous motor behaves compared to an induction motor • What a variable frequency alternator actually changes in the power supplied to the motor

💭 Think About

• Think about the formula that links synchronous speed to electrical frequency and motor construction. Which terms in that formula can the alternator realistically change while the ship is operating? • Ask yourself: in a turboelectric drive, what does the turbine actually drive, and what electrical quantity does that affect? • Consider which options would require physically changing the motor versus which can be adjusted smoothly during operation.

✅ Before You Answer

• Recall the synchronous speed formula and identify which variables are electrical frequency and number of poles. • Decide which of the choices can be adjusted continuously while underway without rewiring or rebuilding machinery. • Verify which component (generator/alternator vs. motor) is responsible for setting the frequency of the power supplied to the propulsion motor.