PROLONG LIFE OF COOLER PUMP And Save Electricity Too

With this proposed system you can prevent your water cooler's motor from dry running and activate it for about one third of the time only.

- SURESH DWIVEDI

This will reduce wear and tear of the motor and save electricity too. Coolers are used at many homes, offices, schools, and industries, especially in summers, so this device will come handy to stop the cooler pump automatically when the cooler's tank has no water.

The author's prototype is shown in Fig. 1 and its circuit diagram is shown in Fig. 2. The circuit comprises stepdown transformer X1, bridge rectifier BR1, 5V voltage regulator LM7805 (IC1), decade counter 4017 (IC2), rectifier diode 1N4007 (D1), signal diode 1N4148 (D2-D5), NPN transistor 2N2219 (T1), 5V single changeover relay, and a few other components.

The 5V DC supply required for the circuit is derived from 230V AC to 9V, 500mA step-down transformer X1. The 230V AC mains is connected to primary winding of X1 via CON1 in the circuit. The secondary winding of X1 produces 9V AC, which is connected to bridge rectifier BR1 for rectification and to capacitor C1 for filtration. The rectified and filtered voltage is given to regulator IC LM7805 (IC1) to get regulated 5V for the circuit, whose presence is confirmed by the glowing of LED1.