Term Examination - Part 1

A pump running at 100 rpm delivers water against a head of 30 m. IF pump speed will increase to 120 rpm, what is the increase in head?

• 43.2 m
• 13.2 m
• 34.6 m
• 56.3 m

A pump is used to deliver 50 li/sec of sea water at a speed of 120 rpm. If speed will increase to 135 rpm, determine the increase in pump capacity.

• 56.25 li/sec
• 34.56 li/sec
• 87.54li/sec
• 6.260 li/sec

A 15 kW motor running at 350 rpm is used to drive a pump. If speed will be changed to 370 rpm, what is the increase in power?

• 2.72 kW
• 17.72 kW
• 56.45 kW
• 5.67 kW

A centrifugal pump is designed for 1800 rpm and head of 61m. Determine the speed of impeller if diameter is reduces from 305 mm to 254 mm.

• 1000 rpm
• 1250 rpm
• 1500 rpm
• 1600 rpm

A pump delivers 500 gpm of water against a total head of 200 ft and operating at 1770 rpm. Changes have increased the total head to 375 ft. At what rpm should the pump be operated to achieve the new head at the same efficiency?

• 2800 rpm
• 3600 rpm
• 3434 rpm
• 2424 rpm

A fan using standard air condition can develop a static pressure head of 310 mm water gage. If fan will operate 93°C and 735 mm of Hg, find the new static pressure required.

• 150 mm water gage
• 180 mm water gage
• 241 mm water gage
• 456 mm water gage

A fan delivers 4.7 m/sec at a static pressure of 5.08 cm of water when operating at a speed of 400 rpm. The power input required is 2.863 kW. If 7.05 m/sec are desired in the same fan and installation, find the pressure in cm of water.

• 7.62
• 17.14
• 11.43
• 5.08

A fan described in a manufacturer’s table is rated to deliver 500 m/min at a static pressure (gage) of 254 cm of water when running at 250 rpm and requiring 3.6 kW. If the fan speed is changed to 305 rpm and air handled were at 65% instead of standard 21°C, find the power in kW.

• 3.82
• 5.08
• 4.66
• 5.68

A pump operating at 1750 rpm delivering 500 gal/min against a total head of 150 ft. Changes in the piping system have increased the total head to 360 ft. At what rpm should the pump be operated to achieve this new head at the same efficiency?

• 2730 rpm
• 2740 rpm
• 2711 rpm
• 2600 rpm

A pump delivers 500 gpm of water against a total head of 200 ft and operating at 1770 rpm. Changes have increased the total head to 375 ft. At what rpm should the pump be operated to achieve the new head at the same efficiency?

• 2800 rpm
• 3600 rpm
• 3434 rpm
• 2424 rpm