Examples of Fault Finding

Example 1: Diagnosing an Overheating Pump Motor

1. Start the Fault-Finding Process

  • Observation: Begin by noting symptoms, such as the motor overheating or emitting a burnt smell.

  • Preparation: Gather any available data, including maintenance history and recent operational changes.

2. What to Look For

  • Look for visual signs of overheating like discolored or burnt insulation on wires.

  • Check for blockages, dust, or debris around the motor and fan housing.

3. Techniques to Use

  • Thermography: Use an infrared thermometer or camera to check if the motor or bearings are excessively hot.

  • Vibration Analysis: Use a vibration analyzer to detect any unusual vibrations that could indicate misalignment or bearing wear.

  • Current Testing: Use a clamp meter to check if the motor is drawing more current than specified, which could indicate an overload.

4. Solve the Problem

  • Bearing Inspection: Disassemble the motor to inspect bearings. If they’re worn, replace them.

  • Alignment Check: Realign the motor and pump shaft if misalignment is detected.

  • Lubrication: Add or replace lubricant if it’s degraded or insufficient.

  • Overload Investigation: Check for factors causing overload, such as an obstructed impeller or over-demand on the system, and clear any blockages.

5. Test Equipment Health

  • Reassemble the motor and perform a run test, monitoring for excessive heat and vibration.

  • Use current and temperature measurements to confirm they’re within acceptable ranges.

  • Conduct a performance test with a normal load and verify that the motor runs smoothly without overheating.

Example 2: Troubleshooting Hydraulic Cylinder Leak

1. Start the Fault-Finding Process

  • Observation: Check for hydraulic fluid leakage around the cylinder and piston.

  • Preparation: Review the system’s recent maintenance records and ensure the hydraulic fluid level is adequate.

2. What to Look For

  • Look for visible leaks around seals and piston rod.

  • Inspect hoses and fittings for any wear or loose connections.

3. Techniques to Use

  • Visual Inspection: Examine seals, hoses, and cylinder body for cracks, cuts, or damage.

  • Pressure Testing: Apply pressure to the hydraulic system to detect leaks or weak seals.

  • Ultrasonic Testing: Use an ultrasonic detector to pinpoint the exact location of any minor leaks.

4. Solve the Problem

  • Seal Replacement: Replace worn or damaged seals.

  • Hose/Fitting Repair: Tighten or replace any loose or damaged hoses and fittings.

  • Cylinder Rod Inspection: Inspect and replace the cylinder rod if it’s bent or damaged, as this can cause further leaks and wear.

5. Test Equipment Health

  • Refill the hydraulic fluid, bleed air from the system, and run the cylinder through its full range of motion.

  • Monitor for leaks under full pressure and check that the cylinder operates smoothly.

  • Perform a leak test by observing the cylinder under load for an extended period.

Example 3: Addressing Excessive Vibration in a Conveyor System

1. Start the Fault-Finding Process

  • Observation: Note where the vibrations are most intense and whether they occur at specific operational speeds.

  • Preparation: Ensure that all safety guards are in place, and review the maintenance history of the conveyor.

2. What to Look For

  • Check for loose components such as bolts, belts, or couplings.

  • Inspect rollers, bearings, and motor mounts for wear or misalignment.

3. Techniques to Use

  • Vibration Analysis: Use accelerometers to measure vibration frequencies and amplitude, which can help locate imbalances or misalignments.

  • Alignment Check: Use laser alignment tools to check the motor and pulley alignment.

  • Bearing Inspection: Use a stethoscope or ultrasonic tester to listen for unusual noises indicating bearing wear.

4. Solve the Problem

  • Balancing: Balance the conveyor belt by adjusting tension or adding weights if necessary.

  • Replace Worn Bearings: If bearings are worn or noisy, replace them with new ones.

  • Align Motor and Pulleys: Correct any misalignment to reduce vibration.

5. Test Equipment Health

  • Restart the conveyor and monitor vibration levels to confirm a decrease in amplitude.

  • Conduct a test run under load to ensure the system operates smoothly and within acceptable vibration limits.

  • Re-measure vibration levels to confirm they are within the manufacturer’s recommendations.

Example 4: Diagnosing Low Pressure in a Pneumatic System

1. Start the Fault-Finding Process

  • Observation: Note pressure readings and listen for any hissing sounds indicating a possible leak.

  • Preparation: Confirm the system is at the required pressure setting and that the compressor is operational.

2. What to Look For

  • Inspect hoses, seals, and fittings for signs of wear, leaks, or disconnections.

  • Check the air compressor and associated components for clogging or wear.

3. Techniques to Use

  • Ultrasonic Leak Detection: Use an ultrasonic detector to find small air leaks in hoses, fittings, or valves.

  • Pressure Testing: Measure pressure at various points to locate any significant drops, which may indicate a blockage or leak.

  • Flow Meter Testing: Check flow rates to determine if obstructions or restrictions are causing low pressure.

4. Solve the Problem

  • Seal Replacement: Replace any faulty seals or gaskets.

  • Hose/Fitting Repair: Tighten or replace any damaged hoses or fittings.

  • Filter Replacement: Replace any clogged air filters that may be restricting airflow.

5. Test Equipment Health

  • Re-pressurize the system and check for consistent pressure readings.

  • Perform a leak test under full pressure and listen for air leaks.

  • Confirm that the system maintains proper pressure during operation and observe for any additional leaks or pressure drops.

Example 5: Solving Reduced Output from a Centrifugal Pump

1. Start the Fault-Finding Process

  • Observation: Observe pump output and check for cavitation or low flow.

  • Preparation: Gather recent performance data, such as flow rate, pressure, and temperature.

2. What to Look For

  • Look for blockages in the intake or discharge lines.

  • Inspect the impeller for signs of wear, damage, or clogging.

3. Techniques to Use

  • Visual Inspection: Check for visible blockages or restrictions in the suction line or impeller.

  • Pressure Testing: Use a pressure gauge to verify inlet and outlet pressures.

  • Thermography: Check for temperature increases around the pump housing, which could indicate cavitation or friction.

4. Solve the Problem

  • Impeller Cleaning/Replacement: Clean the impeller or replace it if it’s damaged or clogged.

  • Check and Clear Suction Line: Remove any obstructions from the intake line.

  • Adjust Pump Settings: Adjust the flow rate or speed settings as needed.

5. Test Equipment Health

  • Reassemble the pump and conduct a test run, measuring flow rate and pressure.

  • Monitor for cavitation noises and confirm that the pump operates at its rated flow capacity.

  • Compare current performance data to previous benchmarks to confirm the issue is resolved.