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A hoisting system has a drum of 750 mm with 25 mm wire rope diameter, mounted on the same shaft with a worm gear having 90 teeth. A triple threaded worm is to drive the wheel and this system is to raise a 25 kN load a a speed of 24m/min. If the system has an efficiency of 70%, how much power should be supplied to the worm’s shaft? What is the torque on the worm’s shaft?
Efficiency = (Power out) / (Power in)
The pinion of a pair of helical gears mounted on parallel shafts is to transmit 4 kW at 8000 rpm. Both gears have 30 degrees helix angle, 20 degrees normal pressure angle and are made of SAE 1040 HR steel with face width of 12 mm. If the pinion has 25 teeth and gear has 100 theeth, what are the minimum gear diameters and what is the required hardness for pinion as BHN, if it needs heat treatment for surface hardness. Take Quality level 7 and safety factor 1.5. Consider strength for size calculations and wear for BHN determination.
A reheat cycle with two stages of reheating is executed with steam expanding initially from 20 MPa and . The two reheater pressures are 3.8 MPa and 0.97 MPa, and the steam leaves each reheater at . Condensation occurs at . Compute for for a 1kg/s of steam.
Air at 1 bar and 27°C is heated in a non flow system at constant pressure to 177°C. Heat is supplied from a constant temperature reservoir at 577 °C. The atmospheric temperature is 20 °C. Calculate the available energy.
A room (10 m× 5 m × 5 m)contains moist air at 38°C / 1 bar with relative humidity 70%. Determine the specific humidity?(where, Corresponding to the dry bulb temperature of 38° C, the saturation pressure of water vapour Ps=0.06624, From the Steam Table)
A multistage reciprocating compressor runs at 900 rpm and delivers 3 kg per minute of air. It takes in air at 1 bar, 25° C and compresses it to 20 bar. All pistons have a stroke of 170 min.Calculate the index of compression?
An input shaft connected to the motor rotates at 1200 rpm, while the output speed must be 570 rpm. The contact force between the gears is transmitted through the pressure angle of 20°. The radial
force is 321,90 N. The material for both gear and pinion is 817M40.
Use table 6.8 on page 126 to select the suitable gear and pinion (make use of the (35) Lewis formula). Then, do one set of calculations and tabulate the answers.
An input shaft connected to the motor rotates at 1200 rpm, while the output speed must be 570 rpm. The contact force between the gears is transmitted through the pressure angle of 20°. The radial
force is 321,90 N. The material for both gear and pinion is 817M40.
Steam enters a converging-diverging nozzle operating at steady state with P1= 40 bar. T1= 400°C, and a velocity of 10 m/s. The steam flows through the nozzle with negligible heat transfer and no significant change in potential energy. At the exit, P2= 15 bar, and the velocity is 665 m/s. The mass now rate is 2 kg/s. Determine the exit area of the nozzle in m2.
What is the difference between a vice grip and a wrench in terms of their structure and functions?
