DESIGN AND CONSTRUCTION OF AUTOMATIC TRANSFER SWITCH

ABSTRACT Power instability as a result of rapid changes in voltage levels, such as surges and sags, brief interruptions or complete power blackouts, sudden, sharp increases in voltage, changes in the frequency of alternating current (AC) power can damage sensitive electronic equipment at worst damage electrical appliances and even disrupt operation of industries. These challenges necessitates the need for an alternative or emergency source of power supply switches. Over time, manual switches have been utilized; however, the process of manually switching between mains power and backup generators continues to be both cumbersome and susceptible to potential errors. Hence, the needs for an automatic transfer switch (ATS). ATS device automatically switch power sources under predetermined conditions. To achieve this, a design and construction of an automatic transfer switch that ensures a seamless transition between power sources, cost effective and efficient was carried out using discrete components. The testing of the constructed automatic transfer switch (ATS) involved a thorough examination of every practical step to ensure the system's proper functionality. This included steps like powering off the ATS, connecting it to the primary power source (mains), and subsequently powering it on. The output voltage from the power supply unit was measured and verified. The voltage monitor components were connected, reference voltages were set, and their response to various voltage conditions was observed to ensure accurate detection. Additionally, the relay components, opto-isolator, shunt regulator, and backup battery were connected, and their functions were validated by simulating different power source scenarios, including primary source failure. This testing process confirmed that the ATS system operates as intended and effectively switches between power sources based on voltage conditions. The functionality test of the ATS was successfully carried out and the assessment of the power supply unit revealed its ability to consistently deliver the necessary voltages for ATS components. Additionally, testing the LM324 voltage comparator demonstrated its capability to trigger relay switching when the input voltage surpassed 5V for both high and low voltage monitoring. Moreover, the switching section exhibited effective operation, responding appropriately to power source availability. This study recommends the substitution of a switching power supply in lieu of a manual power changeover to enhance efficiency and solve energy challenges.