Electrical Wiring and installation of Direct On Line – DOL …

Method of Wiring - for Three Phase DOL Motor

The Main contactor has three NO contacts and one NO and NC Auxiliary contacts. A thermal overload relay is shown in the example but one can use only a contactor without the overload unit. If a thermal overload unit is used, it's rating should correspond to the motor running amperage.

Install the 415 V coil contactor in a suitable enclosure and fix the On/Off Push Button switches at the required operating point.

Wire from a 3 Phase power supply of a 3 Pole MCB or a Main switch of the Power Distribution to the L1,L2 and L3 terminals of the contactor. If a Thermal overload is connected to the contactor's T1,T2 and T3 terminals, then connect the load wires to the motor to the T1,T2 and T3 terminals of the thermal overload.

Now for the control wiring.

Connect a wire to L1 terminal and connect the other end to a terminal of the On Push Button.

Connect the other terminal of the On Push Butto to the terminal of the Off Push button.

The remaining therminal of the OFF Push button should be wired to one of the Thermal Overload's NC contact terminal.

The other terminal of the Thermal Overload's NC contact should be wired to the coil terminal A1 of the contactor.

[ If a Thermal overload is not used, then the remaining therminal of the OFF Push button should be wired to A1 terminal of the contactor.]

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Electrical Wiring and installation of Direct On Line - DOL ...