Wednesday, November 2, 2016
THREE PHASE INDUCTION MOTOR SAFETY IMPLEMENTATION
THREE PHASE INDUCTION MOTOR SAFETY IMPLEMENTATION
ABSTRACT:
The common problem with three-phase supply is, absence of any one of the phase. This leads to damage of induction motor or any three-phase load. This project is designed to monitor the presence of three phases and to display condition of each phase on an LCD. If any phase is absent, immediately this system shuts down the three-phase load. If all the three phases are present, automatically this system switches on the load.
This project is also designed to monitor the voltage condition of each phase. If the voltage level of any phase is over or under the rated / specified voltage rating, immediately this system shuts down the load. Operational amplifier IC LM324 is used here as a comparator. IC LM324 consists of four operational amplifiers, of which only two operational amplifiers are used in the project.
When the AC voltage increases beyond 240V, the voltage at the non-inverting terminal of operational amplifier increases. The voltage at the inverting terminal is still 6.8V because of the zener diode. Thus if the voltage at pin 3 of the operational amplifier is higher than 6.8V, the output of the operational amplifier goes high to drive transistor T1 and hence energise relay RL. Consequently, the AC supply is disconnected and electrical appliances turn off. Thus the appliances are protected against over-voltage. Now let’s consider the under-voltage condition. When the line voltage is below 180V, the voltage at the inverting terminal of operational amplifier is less than the voltage at the non-inverting terminal (6V). Thus the output of operational amplifier goes high and it energizes the relay through transistor. The AC supply is disconnected and electrical appliances turn off. Thus the appliances are protected against under-voltage.
BLOCK DIAGRAM:
Phase fault detector
If you want to buy this project, drop email on technofieldsystems@gmail.com
Available link for download
