Exam Question
(a) How is Shaft Power obtained from Torque measurement? (4)
(b) What is procedure for measuring Torque on Propulsion shaft? (4)
(c) Drawing a Diagrammatic sketch Describe the working of a Strain-Gauge Torsionmeter (8)
Class 4 (4th Engineer)
MEKM
📅 Jun 2023
Reference Answer
### (a) Obtaining Shaft Power from Torque Measurement (4 Marks)
Shaft Power is the rate at which work is done by the rotating propulsion shaft. It is a direct function of two key parameters: the Torque applied to the shaft and its Rotational Speed.
1. **Torque (T):** This is the turning or twisting moment applied to the shaft by the main engine. It is measured in Newton-metres (Nm) or kilo-Newton-metres (kNm). The measurement is typically accomplished using a torsionmeter, as detailed in part (c).
2. **Rotational Speed (N):** This is the angular velocity of the shaft, measured in revolutions per minute (RPM) or radians per second (rad/s). This is measured using a tachometer or a shaft encoder.
Shaft Power is the rate at which work is done by the rotating propulsion shaft. It is a direct function of two key parameters: the Torque applied to the shaft and its Rotational Speed.
1. **Torque (T):** This is the turning or twisting moment applied to the shaft by the main engine. It is measured in Newton-metres (Nm) or kilo-Newton-metres (kNm). The measurement is typically accomplished using a torsionmeter, as detailed in part (c).
2. **Rotational Speed (N):** This is the angular velocity of the shaft, measured in revolutions per minute (RPM) or radians per second (rad/s). This is measured using a tachometer or a shaft encoder.
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