Requirements3 phase induction motor
3 core electric cable
Three phase 4 wire system supply (three phase and one neutral)
A circuit breaker
A contactor or stater
A overload relay
and flexible wiring cable for cotactor coil and button wiring
Normal close push button
Normal open push button
Before we starting talking about the wiring and wiring diagram, first we disuse the above substance . We required 3 core cable, a three core cable is a cable which have internal three electric cable which mostly in red, yallow and blue colors. The three phase 4 wire system supply means that we need 3 phase electric supply and one neutral wire. Note that we use the neutral wire for contactor coil wiring which we called the small wiring.
We also required the circuit breaker which are 3 pole circuit breaker or circuit breaker which can cutoff the 3 electrical connection in same time.
Normal close push button (NC) means that we need a push button which is normally have close electric circuit and when we push it then the button switch off the connection or change to the open electric circuit.
Normal open push button mean that we need a push button which have a open electric circuit in normal state and when we push it then it's change to the close electric circuit.
3 Phase Induction Motor Wiring with Contactor Wiring DiagramTo wire a 3 phase motor the first thing to wire is a circuit breaker which is disconnect and connecting point then we will get the supply form circuit breaker and connect supply to contactor or starter and then to overload relay. We connect the circuit breaker, contactor and overload relay in series between electrical supply and motor as shown in below diagram.
Update Diagram For Direct Online starter So use the diagram.
Contactor and overload Wiring
In a contactor we have a magnetic coil which is use for switching. We have also NC and No point in a contactor which we can use for many connections. In overload relay we have an input and output points. In normally overload points have a close electric circuit between point but when ever the ampere or load is getting high the overload relay switch off or make an open electric circuit between these two point or connection. So we wire the overload relay in series between the cotactor coil current.
So for contactor wiring first of all connect the neutral wire to contactor coil first terminal and then connect a wire form the one output terminal of circuit breaker which is opposite or phase current for contactor coil. In this process the small wiring which contactor wiring is also control by breaker and when we switch off the breaker, then contactor will stop working auto.
The small wiring wire which connect form the breaker output terminal will goes to the NC push button and then from NC push to the overload relay and NO push button as shown in above diagram. Then we connect a wire between the 2nd terminal of overload relay and this wire goes to the NO point of contactor and then form NO point wire is goes to the 2nd terminal of contactor coil.
Then in last we connect a were between NO push button switch and contactor 2nd terminal of coil where we connect the phase wire of contactor as shown in above diagram. And this wire connection is called tech current.
Final wordNote that in all wiring use the best quality breaker, push button switches, contactor and overload relay. If your overload relay in not good then it will be not trip and if the overload relay does not trip or not switch the point then it will be case of your motor burn. Note that do all wiring control able from circuit breaker as i shown in above diagram.
Note that always connect the earth wire to motor, and adjust the overload relay ampere by using the adjustment switch.