Circuit diagram: Shown in the circuit diagram tab
As we give three phase supply to the circuit:
R phase passes through the step-down transformer X1. This step-down transformer reduces the voltage to 12V AC. Rectifier circuit rectifies the 12V AC to 12V DC. As the output appear at rectifier circuit 1 then LED glows. Rectifier circuit 1 gives the 12V DC to coil of relay RL1. When coil of relay RL1 gets triggered its pole connects to the NO.
Then phase Y given to pole of relay RL1 passes to transformer X2 through NO. Then Y phase passes from the step-down transformer X2. This step-down transformer reduces the voltage to 12V AC. Rectifier circuit rectifies the 12V AC to 12V DC. As the output appear at rectifier circuit 2 then LED glows. Rectifier circuit 2 gives the 12V DC to coil of relay RL2. When coil of relay RL2 gets triggered its pole connects to the NO.
Then phase B given to pole of relay RL2 passes to transformer X3 through NO. Then B phase passes through the step-down transformer X3. This step-down transformer reduces the voltage to 12V AC. Rectifier circuit rectifies the 12V AC to 12V DC. As the output appear at rectifier circuit 3 then LED glows. Rectifier circuit 3 gives the 12V DC to 555 timer. This 555 timer produces the delay to produce the output at pin 3 in order to avoid surges and momentary fluctuations. The time delay can be adjusted by the variable resistor connected at pin 6. The output at pin3 is given to the base of transistor.
Then this output is given to coil of relay RL3 through collector of transistor. When coil of relay RL3 gets triggered its pole connects to the NO. Then phase B given to pole of relay 3 passes to coil of 4pole contactor RL4 through NO.
When coil of contactor gets triggered it connects the three-phase supply to the load. When any one or two phase gets failure in three phase supply then this circuit fails in above operation. As the circuit fails in operation 4-Pole contactor RL4 automatically disconnects the three-phase supply to load.
The test system considered in the project is worked out for the best protection for the 3- phase appliance in absence of any of the phase. The main objective of this prospective protector is to maintain the efficiency of the appliance which we use with the 3- phase supply. The 4-pole contactor locking assures the presence of all the 3-phases. Remaining three relays placed for all the three phases show there working with a hissing sound and glowing LED’S. Due to any erratic action taking place there will be absence of any o the phase results in the un-locking of the 4- pole contactor with an rapid fast off sound. The 555 timer which we used in the destination tip of the circuit provides the time delay for each phase which would be around 4sec as the timer working in astable mode.For review time delay from the 555 timer we need to connect an variable resistor due to that time delay can subjected and maximum is upto 4 sec.A transistor is placed in need of a switch which is used for getting the output in the third phase. Using this protector scheme would be useful to protector the appliance and at the same time it would reduce the frequent money lending in fault occurrence or failure of the appliance.