Troubleshooting and Solutions for Common Motor Fuse Failures

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I. Fuse Blowing During Motor Start-up​
​Common Causes and Solutions:​​​

1. ​Fuse element rating is too small.​​
   Solution: Replace with a fuse element of appropriate rating that meets the motor’s starting current requirements.
2. ​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.
3. ​Mechanical damage during fuse installation.​​
   Solution: Replace with a new, undamaged fuse element, and avoid bending or squeezing during installation.
4. ​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:​​

1. ​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.
2. ​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:​​

1. ​Loose terminal screws.​​
   Solution: After power-off, re-tighten all connection screws in the conductive circuit.
2. ​Poor crimping due to corroded screws.​​
   Solution: Replace corroded screws and washers to ensure secure cable fixation.
3. ​Oxidation or corrosion on the contact blade and blade seat.​​
   Solution: Remove oxidation with sandpaper and apply conductive paste to improve contact.
4. ​Fuse element rating is too small.​​
   Solution: Recalculate based on the actual load current and replace with a matching fuse element.
5. ​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​

1. ​Regularly inspect magnetic insulation components.​​
   If damage or carbonization is found, replace them immediately after power-off to prevent arc short circuits.
2. ​Quality issues and external damage.​​
   If defects such as cracks or deformation are found, replace immediately with an original model product.
3. ​Operational standards.​​
   Use specialized tools when replacing fuses to avoid excessive force that may break ceramic parts.
4. ​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.