Reverse-Forward Starter Control Wiring Diagram
Learn reverse-forward starter control wiring for 3-phase motors with contactors, overload protection, and safe input-output connections for motor control.
3-phase motor forward reverse control
A reverse-forward starter enables the 3-phase motor to operate in each direction. Safe operation and directional control are provided by two contactors, a stop/start control circuit, and an overload relay.
forward reverse motor relay diagram
To switch the direction of rotation of a 3-phase motor, a reverse-forward starter is employed. Two contactors are used, including forward rotation and reverse rotation, and an overload relay is used to protect the wiring. The contactors have the common terminals to which the line supply is attached. The forward contactor links phases L1, L2, and L3 directly to the motor to provide a forward rotation, and the reverse contactor provides a reverse rotation by swapping either of L3↔L1 or L2↔L3. An interlock control circuit is used to prevent short circuits by ensuring that both contactors are not energized at the same time. The overload relay terminals are connected with the supply to the motor in order to break the circuit in the event of current overload. In the industrial and commercial applications, good installation is used to provide safe motor start/stop, directional control, and overload protection. Checking entails ensuring that the rotation is correct on the forward and reverse modes and that overload trips are correct.
Work & Installation (Input → Output Summary)
- Connect3-phase supply to common terminals of forward and reverse contactors.
- Connectmotor terminals to output contacts of contactors.
- Wirestart (forward/reverse) and stop push buttons in series with the contactor coils.
- Includemechanical or electrical interlock to prevent simultaneous forward and reverse activation.
- Connectoverload relay in series with the motor supply.
- Verify properphase sequence for desired forward rotation.
- Mount contactors, overload relay, and push buttons securely.
- Test motor operation in forward and reverse directions.
Testing & Final Adjustments
- Checkline connections to contactors and motor.
- Teststart/stop buttons for correct coil energization.
- Verify interlocking prevents both contactors from energizing simultaneously.
- Observe motor rotation for forward and reverse directions.
- Adjustoverload relay settings to match motor full-load current.
- Ensure fuses or MCBs are correctly rated.
- Inspect for loose connections and secure mounting.
- Perform multiple start/stop cycles to check reliability.
- Confirm correct operation of auxiliary contacts if used.
- Document wiring, settings, and test results for maintenance.
Frequently Asked Questions - Reverse-Forward Starter Control Wiring Diagram:
What is a reverse-forward starter?
A starter that allows a 3-phase motor to run in both forward and reverse directions.
How many contactors are used?
Two contactors, one for forward and one for reverse operation.
Why is interlocking needed?
To prevent simultaneous activation of both contactors which could cause a short circuit.
What is the role of the overload relay?
To protect the motor from overcurrent by tripping the circuit if necessary.
How are motor rotations reversed?
By swapping two phases of the motor supply using the reverse contactor.
Can push buttons control the starter?
Yes, start/stop push buttons are used for forward and reverse control.
Is phase sequence important?
Yes, proper phase sequence ensures correct forward rotation.
Can it be used in industrial motors?
Yes, commonly used in industrial and commercial 3-phase motor applications.
Do I need MCB or fuses?
Yes, for overload and short circuit protection.
How to test the starter?
Check motor rotation in forward and reverse modes and test overload relay operation.
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