Motor Failure Analysis: Enhancing Reliability Through Root Cause Diagnosis

With the level of industrial automation increasing, the motor is a key component of the drive system, and its operating state impacts the efficiency and stability of the entire equipment. It does not matter if it is a high-priced imported or high-efficiency energy-saving domestic motor, all sorts of faults will occur in long-term operation. If the fault is not properly analyzed and diagnosed, it will normally result in reoccurring faults, excess maintenance costs, and even affect the production rhythm of enterprises.

This article attempts to organize from the five modules of motor fault type, common symptoms, cause analysis, diagnostic methods and preventive measures the core knowledge of motor fault analysis for you.

I. Common types of motor faults

II. Identifying symptoms and preliminary diagnosis

While a motor is in operation, five types of signals should be monitored more closely:

1. Changes in noise: Noise changes, like "clicking" and "clucking" - most often either bearing wear or rotor eccentricity.

2. Increased vibration: Rotor imbalance or misalignment of the coupling.

3. Increased temperature rise: Typically poor heat dissipation or increased loss inside.

4. Unusual frequent tripping: Electrical insulation issues (degradation of insulation), short circuit protection, or overload protection.

5. Difficulty in starting: May be missing one power phase, faulty capacitor, or unusual external load.

Recommendation: This secondary detection approach combining methods such as infrared thermometer, vibration analyzer, and current clamp-on meter, will aid identifying the problem with precision.

III. Common causes of motor failure analysis

1. Design problem

Some non-standard motors are not designed in a reasonable way, in exposing the magnetic circuit saturation or insufficient cooling structure, which results as a defect in its initial operating state.

2. Wrong selection

Power rating, number of poles, speed and load dla are not correctly matched, and thus it started operating for a long period in an overload state, which resulted in 'aging'

3. Non-standard installation

Stand still un-even footings, loose coupling and incorrect cable wiring are important reasons for abnormal operations.

4. No daily maintenance

Lack of lubrication, dust packing, and no regular cleaning of windings will affect the operating stability and efficiency of heat dissipation.

5. Environmental issues

Bad environmental conditions don't help i.e. humid, high in salt spray, dust, etc., affecting insulation degradation or parts corrosion.

IV. Analysis tools and method for fault analysis

V. Prevention recommendations and optimization suggestions

1. Establish equipment history files: such as operation hours, maintenance history, load conditions etc., are of value to assess maintenance cycles and performance trends.

2. Establish an inspection rhythm: check the key operating parameters once a month and full inspections on insulation and vibration quarterly.

3. Optimize the operating environment: the operating site for the motor must be dustproof, moisture-proof and anti-corrosion, with auxiliary equipment such as filter and heater, etc in place as required.

Reasonable spare parts reserves and technical support: Reserve for all necessary bearings, brushes, seals & etc, along with spare parts patterns based on motor model and service years to avoid waiting cycles.

VI. Sharing of a typical failure case

Customer Background: An automation equipment company

Problem Phenomenon: Abnormal noise during turnkey operation of the motor resulting in a frequent alarm shutdown

Fault Analysis: Upon disassembly, it was discovered that the shaft was slightly bent, causing uneven gaps between the rotor (induction motor) and stator, resulting in sweeping of the rotor.

Solution: Replace bearings, calibrate shafts, re-dynamic balance

Final Result: Operation recommenced stable, current consumption fell down approximately 12%, energy efficiency significantly improved.