A Direct-On-Line (DOL) starter is one of the simplest methods used to start a motor. In this guide, you will learn how to wire a DOL starter step by step, even if you are a beginner.
What You Need
Contactor
Overload relay
Start push button (NO)
Stop push button (NC)
Motor
MCB
Step 1: Understand the Circuit
Before wiring, you need to understand that a DOL starter consists of:
- Power circuit (main supply to motor)
- Control circuit (start/stop operation)
Control circuit
Power circuit
Step 2: Connect the Power Circuit
- Connect the three-phase supply to the contactor input
- Connect the output of the contactor to the overload relay
- Connect the overload relay to the motor terminals
Step 3: Wire the Control Circuit
- Connect the Stop button (NC) in series
- Connect Start button (NO)
- Connect the contactor coil
- Add holding contact (self-latching)
Step 4: Test the Circuit
- Press Start → motor should run
- Press Stop → motor should stop
Common Mistakes
- Wrong wiring of the overload relay
- Missing holding contact
- Incorrect push button connection
Conclusion
Wiring a DOL starter becomes simple when you understand both the power and control circuits. Practice this setup to master motor control basics.
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