Construction of a Power Source Protective Device

Abstract

One of the major problems encountered in power electronics is that associated with voltage irregularity and instability (excess or under voltage). Devices from simple Cut-off fuse to sophisticated voltage Regulators, TV guards, etc. have been built to protect appliances and keep them functioning optimally. This is protecting appliances from power sources. What about protecting power sources against appliances? When appliances demand more power than a source is capable, it often leads to interruption in the operation or sometimes damages in the power source. In this work, we have designed, constructed and tested an electronic device to protect low power sources (such as domestic electric generators, inverter systems, etc.) especially when an attempt to drive heavy power appliances is made. This device was designed based on the operation of automatic switches which make use of microcontrollers. Use was made of a 10A relay that switches the line, a relay driver circuit to drive the main relay, an arduino Uno board that contains the set of instructions, a dc power supply, a 15A socket, a pushbutton switch and two indicator lights. The testing showed that generally, appliances connected to the device will not get energized, even though the appliance's power button is ON. At this point, only a red LED will be glowing showing that the device is receiving power but the power is not transferred to the load. When the user is sure that the power source can drive the appliance(s), the pushbutton switch is pressed and the green LED also begins to glow, showing that the appliance is powered. This result is exactly what the circuit is meant to achieve.