Troubleshooting and Solutions for Common Motor Fuse Failures
I. Fuse Blowing During Motor Start-up
Common Causes and Solutions:
- Fuse element rating is too small.
Solution: Replace with a fuse element of appropriate rating that meets the motor’s starting current requirements. - Short circuit or ground fault in the protected circuit.
Solution: Use an insulation resistance tester to inspect sections of the circuit, locate the fault point, and repair it. - Mechanical damage during fuse installation.
Solution: Replace with a new, undamaged fuse element, and avoid bending or squeezing during installation. - Open phase in the power supply.
Solution: Use a multimeter to check the circuit breaker and circuit continuity, and repair any open points.
Note: If the fuse element is intact but the circuit is not energized, further investigate the following issues.
II. Circuit Not Energized Despite Intact Fuse Element
Common Causes and Solutions:
- Poor contact between the fuse element and connecting wires.
Solution: Re-tighten the terminal connections and ensure the contact surfaces are clean and free from oxidation. - Loose fastening screws.
Solution: Thoroughly inspect the fuse holder and connection points, and tighten all screws and nuts.
III. Handling Fuse Overheating
Common Causes and Solutions:
- Loose terminal screws.
Solution: After power-off, re-tighten all connection screws in the conductive circuit. - Poor crimping due to corroded screws.
Solution: Replace corroded screws and washers to ensure secure cable fixation. - Oxidation or corrosion on the contact blade and blade seat.
Solution: Remove oxidation with sandpaper and apply conductive paste to improve contact. - Fuse element rating is too small.
Solution: Recalculate based on the actual load current and replace with a matching fuse element. - Ambient temperature is too high.
Solution: Improve ventilation for heat dissipation or install heat insulation devices to prevent exceeding the fuse’s allowable operating temperature.
IV. Safety Maintenance Precautions
- Regularly inspect magnetic insulation components.
If damage or carbonization is found, replace them immediately after power-off to prevent arc short circuits. - Quality issues and external damage.
If defects such as cracks or deformation are found, replace immediately with an original model product. - Operational standards.
Use specialized tools when replacing fuses to avoid excessive force that may break ceramic parts. - Overheating fault handling procedure.
Power off first → Identify the cause of overheating → Resolve the fault → Finally replace the fuse.
V. Preventive Maintenance Recommendations
• Establish a fuse inspection system, focusing on temperature rise and mechanical condition.
• Monitor load current and perform insulation tests on circuits with frequent faults.
• Store spare fuse elements sealed in their original models to prevent oxidation and deformation.
• For critical circuits, consider using fuse status indicators.
Note: All maintenance operations must comply with safety procedures: power-off, verification of de-energization, and grounding.
Through systematic troubleshooting and preventive maintenance, the operational reliability of fuses can be significantly improved, avoiding unplanned downtime.
