International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 06 Issue: 05 | May 2019
p-ISSN: 2395-0072
www.irjet.net
decreases, head increases and efficiency increases up to a certain value and then starts decreasing.
In this study the dimmer-stat was used. It is also known as auto-transformer. A controlling device, it is used in electrical circuits. It consists of a resistance or induction coil which serves like a potentiometer. Dimmer-stat is used to adjust output voltage of an electrical circuit. In resistance type when knob is at zero position, the voltage drop across the resistance is maximum and thus the output voltage will be minimum (0 V). When the knob is kept at maximum position, the voltage drop across the resistance is minimum (maximum voltage). These voltage variations resulted in the speed variation of the motor shaft.
b) Main characteristics curve 14 13 12 11 10 9 8 Head (m) 7 6 5 4 3 2 1 0
3. CIRCUIT CONFIGURATION The centrifugal pump is connected to dimmer-stat via ammeter and voltmeter in parallel connection and input power is supplied to dimmer-stat.
2300 rpm 2500 rpm 2700 rpm 2800 rpm Hundreds 0 1 2 3 4 5 6 7 8 9 10 11 12 Discharge (lph) Chart-2: Head vs Discharge
150 140 130 120 110 100 Input 90 80 70 Power (w) 60 50 40 30 20 10 0
2300 rpm 2500 rpm 2700 rpm 2800 rpm 0 1 2 3 4 5 6 7 8 9 10 11 12 Hundreds Discharge (lph)
Fig-6: Circuit diagram of test setup
3. EXPERIMENTATION
Chart-3: Input Power vs Discharge
With the required and available equipments the testing of centrifugal pump test rig setup was done and the main & operating characteristic curves for centrifual pump were plotted using the recorded observations.
19 18 17 16 15 14 13 12 11 Efficiency 10 (%) 9 8 7 6 5 4 3 2 1 0
a) Operating characteristics curve
2300 rpm 2500 rpm 2700 rpm 2800 rpm 0 1 2 3 4 5 6 7 8 9 10 11 12Hundreds Discharge (lph) Chart-4: Efficiency vs Discharge
Chart -1: Operating characteristics curve Chart-1 shows graph of input power, output power, head and efficiency vs discharge for centrifugal pump by using dimmer-stat for speed variation that indicate as discharge decreases the input power increases, output power increases and reaches its maximum value and then
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