MATERIALS AND METHODS
System description The system designed for the analysis of centrifugal pump performance (Figures 1, 2 and 3) was mounted on a table with a wheeled frame and holding the main water storage tank. The system had the following components: 1) the piping system; 2) a centrifugal pump; 3) a motor dynamometer (2 hp) with a torque arm of 18 cm; 4) a spring balance that could measure up to 5 kg in 0.1 kg increments; 5) an inverter (4.0 KVA) using 380 V, 3 phase, 50 cycle power supply; 6) a digital stationary tachometer, capable of measuring speeds ranging from 5 to 50,000 rpm; 7) a measuring tank recalibrated and capable of holding 120 l of water; 8) a vacuum gauge capable of measuring from -10 to 0 bars, installed on the 4-inch pump inlet; and 9) a pressure gauge measuring from 1 to 10 bars, on the 4-inch pump discharge.