Anna GE 6253 - Work, Power and Torque Problems
School name Anna University
Pages 23

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a machine motor or pump must rotate to produce power Torque Power Torque is defined as the tendency of the force to the rotational objects in a The power of the machinery is denoted by the work done rate specific direction Torque is considered as the vector The power belongs to the scalar quantity quantity It is measured by the newton meter N m that is the SI unit of Torque The Watt W measures it that is the SI unit of Power In order to calculate the torque of the machinery particles The T Frsin In order to calculate the torque of the machinery particles P duration of E formula is also used duration of T formula is also used An engine produces POWER by providing a ROTATING SHAFT which can exert a given amount of TORQUE on a load at a given RPM TORQUE and RPM are the MEASURED quantities of engine output POWER is CALCULATED from torque and RPM by the following equation Horsepower Torque x RPM 5 252 Each can be calculated using the equations below When using units of HP for power and ft lbs for torque the constant is 5252 HORSEPOWER Torque x Speed Constant TORQUE Horsepower x Constant Speed Power is the rate of doing work The relation between torque and power is directly proportional to each other Why is the speed torque curve of a pump not starting from zero Power is product of torque and speed Since power is constant torque is maximum when speed is minimum Mathematically P Tmax Nmin Tmin Nmax torque is zero only when speed is zero rotor is at rest When rotor starts rotating it starts from maximum torque minimum speed point Fluid flow rate area of the pipe velocity of the liquid liquid flow rate Q measured as m3 s or L s A area of the pipe in m2 v velocity of the liquid in m s Calculate the work done by a force of 30 N in lifting a load of 2kg to a height of 10m g 10ms 2 Given Force mg 30 N height 10 m Work done to lift a load W W F S 30x10 W 300 J POWER is the measure of how much WORK can be done in a specified TIME The definition of one horsepower is 33 000 foot pounds per minute The power is the actual rate of the work done that can be measured with the unit of Watt What is the meaning of torque and power in a car in layman terms If you say a car has a particular torque at 3000 rpm and power at 4500rpm what does it mean of a steep hill upward horsepower involves the amount of work done in a given time while torque is simply a measurement of force and is thus a component of horsepower To see how torque and horsepower interact imagine your favorite SUV at the base As the driver begins to press on the throttle the engine s rpm increases force is transmitted from the crankshaft to each wheel and the SUV begins to climb The twisting force going to each wheel as the vehicle moves up the hill is torque Let s say the engine is at 3 000 rpm the gear ratio is 3 and the vehicle is creating 300 pound feet of torque the following horsepower Using Take the torque of 300 multiplied by a shaft speed of 1000 3000 rpm divided by a gear ratio of 3 for a total of 300 000 calculate formula can we Divide 300 000 by 5 252 and you get 57 1 horsepower that the SUV is making as it begins to ascend the hill For instance car moves from a dead stop in 1st or low gear yet as the car s speed increases the gears must be moved up through 2nd 3rd and 4th to maintain This is because at low speeds the transmission s gears work to transmit maximum acceleration torque from the engine to the wheels vehicle in motion Newton s 1st Law it takes more force or torque to move a vehicle that is at rest than it does to move a At the same time once a vehicle is underway you want less torque and more horsepower to maintain a high speed This is because horsepower is a measurement of work done and includes a time element such as wheel revolutions per minute necessary to maintain 75 mph So power at 4500 rpm denotes peak power where as torque at 3000 rpm denotes pulling power The horsepower of a pump can be determined once basic information is known about the pumping station Horsepower is the unit of power to define hydraulic or water horsepower In System International System SI it is in kilowatts kw The hydraulic power is the next energy transferred to the water per unit time Watt is named after the inventor of Scottish scientist James Watt steam engine horse power 1HP lifting 76 kg in one minute and to one meter 1HP 746 watts One horsepower is the amount of power used by a horse to lift a 550 pounds 1 pound 0 45359237 kg heavy object from a depth of 1 foot in one second How do you calculate hydraulic motor Hydraulic power is defined as flow multiplied by pressure The hydraulic power supplied by a pump is Power P x Q 600 where power is in kilowatts kW P is the pressure in bars and Q is the flow in litres per minute How much is 1 horsepower about 745 7 watts kW To convert from horsepower to watts multiply by 746 To convert from watts to horsepower multiply by 0 00134 To convert from horsepower to kilowatts multiply by 0 746 To convert from kilowatts to horsepower multiply by 1 34 A power level of 1 hp is approximately equivalent to 746 watts W or 0 746 kilowatts Torque It is force required to rotate a object around an axis fulcrum or pivot It is just like force which is used to push or pull objects but here it just rotates or twists the object when applied Thus it can be said as turning force or twisting force Torque makes an object undergo rotational motion It is expressed as Torque Force Radius For example Torque is the force exerted on a bolt or screw when tightening or loosening it It is defined as the product of Force applied x Perpendicular distance from the point of force applied Its unit is N m If you have a long lever that you can turn it s easier to turn it e g you have more leverage That s more torque Torque is the ability of the engine to do work remember from physics that work is force x distance Think of the engine as a crank That s more torque If you have a long lever that you can turn it s easier to turn it e g you have more leverage If the engine has more torque it can turn the crankshaft despite more resistance This is great for SUVs and …

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# Anna GE 6253 - Work, Power and Torque Problems

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