Torque Measurement Notes PDF

# Torque Measurement - **Torque:** Force that causes twisting or turning moment. - **E.g:** The force generated by an internal-combustion engine to turn a vehicle's drive shaft. - **Torque measuring devices:** Called as dynamometers ## Formula - $T = F\cdot R$ in N-m - or $F = T/R$ - where:...

# Torque Measurement - **Torque:** Force that causes twisting or turning moment. - **E.g:** The force generated by an internal-combustion engine to turn a vehicle's drive shaft. - **Torque measuring devices:** Called as dynamometers ## Formula - $T = F\cdot R$ in N-m - or $F = T/R$ - where: - $T$ is the torque - $F$ is the force at a known radius - $r$ is the radius ## Types of Dynamometers ### Absorption Dynamometers - Useful for measuring power or torque developed by a power source such as: - Engines - Electric Motors ### Driving Dynamometers - Measure power or torque. - They also provide energy to operate the device to be tested. - They are useful in determining performance characteristics of devices like: - Pumps - Compression ### Transmission Dynamometers - Passive devices placed at an appropriate location within a machine or in between the machine to sense the torque at that location ## Mechanical Dynamometer (Prony Brake) - Consists of wooden cleats or blocks mounted diametrically opposite on a flywheel attached to the rotating shaft whose power is to be determined. - One wooden block carries a lever arm and an arrangement is made to tighten the rope to increase the frictional resistance between the blocks. - The torque exerted by the Prony brake is $T = F\cdot L$ ## Hydraulic Dynamometer - Power sink which uses fluid friction for dissipation of input energy and thereby measures the input torque or power. - The capacity of a hydraulic dynamometer is a function of two parameters: - Speed - Water Level - The torque is measured with the help of a reaction arm or shaft. - The power absorption at a given speed may be controlled by adjustment of water level in the housing. ## Hydraulic Dynamometer Characters - **Small in size:** Easy installation - **Simple dynamometer structure:** Easy for maintenance - **High brake torque:** N/A - **High measurement accuracy:** N/A - **Reliable and stable working condition:** N/A - **High real-time speed measurement accuracy with EM sensors:** N/A - **Fast loading control by electronic-control butterfly valve:** N/A - **High reaction speed which is suitable on dynamic testing:** Suitable - **Tuning of in-use engines, typically at service centers or for racing applications:** Typical application ## Torque measurement is usually associated with determination of mechanical power: - The power required to operate a machine. - The power developed by the machine. ## Formula for determining mechanical power - Power = $(2\pi NT)/(60\cdot 1000)$, $k\cdot w$ - Where: - $N$ = Speed in rpm. - $T$ = Torque developed due to load “W”, (N-m) - $R$ = Radius from the center to the point of application of force (m) ## Image Descriptions - **Page 1**. An image of the formula $T = F\cdot R$. The equation is illustrated with an image of a wrench. - **Page 2.** An image of the formula for determining mechanical power. The formula is $power = (2\pi NT)/(60\cdot 1000)$ - **Page 3.** No image. - **Page 4.** A diagram of the mechanical dynamometer. - **Page 5.** An illustration of a Prony brake. - **Page 6.** An image of the hydraulic dynamometer. - **Page 7.** No image. - **Page 8.** A diagram of the hydraulic dynamometer. - **Page 9.** No image.