By what common means is the speed of an AC...

Question 1 / 2707066636eed28f7522a1c51d3fe

Question 1 of 2707066636eed28f7522a1c51d3fe

By what common means is the speed of an AC propulsion motor on a diesel-electric propulsion ship controlled?

Question 1 of 27070

By what common means is the speed of an AC propulsion motor on a diesel-electric propulsion ship controlled?

🔍 Key Concepts

• AC induction motors and how their speed relates to synchronous speed • The relationship between frequency (Hz) of the supply and motor speed • Why voltage is adjusted along with frequency in practical propulsion drives

💭 Think About

• Think about which electrical quantity directly determines the synchronous speed (RPM) of an AC motor for a given number of poles. • Consider what happens to motor torque and current if you only change voltage but keep frequency constant, or only change frequency but keep voltage constant. • Modern diesel-electric propulsion uses variable-speed drives; what do these typically control to vary motor speed efficiently and safely?

✅ Before You Answer

• Identify which option(s) involve changing frequency, since synchronous speed depends on supply frequency. • Check which method keeps the motor operating with an appropriate volts-per-hertz (V/Hz) ratio to avoid overheating or loss of torque. • Eliminate any choice that would be impractical or unsafe for a large AC propulsion motor in continuous service.

Question 1 of 27070

By what common means is the speed of an AC propulsion motor on a diesel-electric propulsion ship controlled?

by varying either the input voltage or frequency to the motor, but not both

by varying both the input frequency and voltage to the motor

by varying the input frequency to the motor, but not the voltage

by varying the input voltage to the motor, but not the frequency

Question 1 / 2707066636eed28f7522a1c51d3fe

Question 1 of 2707066636eed28f7522a1c51d3fe

By what common means is the speed of an AC propulsion motor on a diesel-electric propulsion ship controlled?

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Question 1 of 27070

By what common means is the speed of an AC propulsion motor on a diesel-electric propulsion ship controlled?