Motor Starter Maintenance Checklist

1. General Safety

• Apply LOTO (Lockout-Tagout) before starting work.
• Use correct PPE (insulated gloves, safety shoes, eye protection).
• Ensure panel/starter enclosure is clean, dry, and grounded.
• Verify motor is isolated from supply before inspection.

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2. Visual Inspection

• Inspect starter enclosure for dust, dirt, or moisture.
• Check for burnt marks, overheating, or loose wiring.
• Ensure all labels, markings, and interlocks are intact.
• Verify cooling fans/ventilation (for soft starters & VFDs).

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3. Electrical Components

• Inspect power contacts/contactors for pitting, wear, or discoloration.
• Check coil condition and operation (pull-in/release smoothly).
• Measure contact resistance across closed contacts.
• Inspect fuses/MCBs/MCCBs for rating and condition.
• Verify busbar and cable terminations are tight.
• Check insulation resistance with megger (control + power wiring).

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4. Protection Devices

• Test overload relays (thermal/electronic) for proper setting and tripping.
• Verify short-circuit and earth fault protection is functional.
• Inspect auxiliary relays and interlocks.
• Check emergency stop push button function.

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5. Control Circuit

• Inspect control wiring for loose or damaged connections.
• Check pushbuttons (Start/Stop/Reset) for smooth operation.
• Test indicating lamps and replace faulty bulbs/LEDs.
• Verify timers (in star-delta starters) for correct settings and functioning.
• Test remote/local control operation (if applicable).

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6. Mechanical Components

• Inspect starter mounting bolts, hinges, and doors.
• Verify mechanical interlocks between contactors (for star-delta).
• Ensure smooth manual operation of switches.
• Clean and lubricate moving parts if required.

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7. Special Checks (Soft Starters & VFDs)

• Inspect heatsinks and cooling fans.
• Verify input/output filters are clean.
• Check VFD parameters/settings against motor nameplate data.
• Monitor fault history log for abnormal events.

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8. Functional Tests

• Energize starter and check pick-up/drop-out voltage.
• Test starter operation without load (simulate start/stop).
• Verify motor starts smoothly and rotates in correct direction.
• Check starting current and voltage drop.
• Monitor for abnormal vibration, tripping, or overheating.

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9. Maintenance Frequency

• Monthly: Visual inspection, pushbutton check, relay operation.
• Quarterly: Contact wear check, insulation test, overload relay test.
• Yearly: Full functional test, contact resistance measurement, calibration of protective devices.

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10. Documentation

• Record test results (IR, contact resistance, overload settings).
• Note any repairs, replacements, or adjustments.
• Maintain starter maintenance logbook with operator name, date, and remarks.

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✅ Tip: For large motors and critical applications, always keep spare contactors, overload relays, and coils in stock to reduce downtime.