i) The design flow rate for a pumped system is 15 m3/hr. At design stage the pump head was estimated as 62 m water. Based on these figures a 2FHE 32-250/55 pump with a 188mm diameter impeller was purchased and installed. When the pump was first run at commissioning stage the volumetric flow rate was found to be 20m3/hr. Calculate the pump power if the design volumetric flow is achieved by

(a) throttling the flow using commissioning valves (4 marks) (b)using a VSD to reduce the pump speed. (6 marks)

(ii) A short level driveway is illuminated by four 1050 cd lamps mounted in a straight line, 6m apart and 4.6m above the driveway surface. Calculate the illuminance on the driveway, midway between any two of the lamps. (10 marks)

(iii) Outline the economics of UPS systems using an example of a 38kVA load being fed from a 78% efficient double conversion UPS. Assume annual maintenance costs of 500, power factor of 0.95 and electricity charges of 0.11/kWh. The capital cost of 85,000 can be written off over

a five year period.

(10 marks