1、 Mechanical structural failure

1. Wear or breakage of transmission components

• phenomenonBelt slippage, chain breakage, and abnormal coupling noise can cause equipment shutdown or decrease in separation efficiency.
• reason：
  • Insufficient or overloaded tension of the belt/chain (such as sudden increase in material flow).
  • Insufficient lubrication leads to bearing or gear wear.
  • The alignment deviation of the coupling exceeds 0.1mm (radial) or 0.05mm (axial).
• process：
  • Adjust the tension of the belt/chain (such as controlling the belt sag within 15-20mm/1000mm span).
  • Replace worn bearings (the model should match the original equipment, such as SKF 6204-2RS).
  • Re calibrate the coupling and use a laser alignment tool to ensure accuracy.

2. Deformation of the box or drum

• phenomenonEquipment vibration intensifies, material leakage or magnetic force decreases.
• reason：
  • Long term overload operation leads to fatigue deformation of the shell.
  • Material impact (such as large pieces of ore) or uneven installation foundation.
• process：
  • Repair the deformed area (annealing treatment is required after welding to eliminate stress).
  • Install collision protection plates (such as manganese steel material) to protect the drum.
  • Reinforce the foundation (using shock-absorbing pads to reduce vibration transmission).

2、 Magnetic circuit system malfunction

1. Magnetic attenuation or failure

• phenomenonMagnetic substances cannot be separatedcleanThe magnetic content in the tailings exceeds the standard (such as a decrease of more than 5% in the grade of iron concentrate).
• reason：
  • permanent magnetLong term high temperature environment (exceeding Curie temperature, such as neodymium iron boron at 80 ℃) leads to demagnetization.
  • electromagnetCoil short circuit, insulation aging (measured by megohmmeter with insulation resistance<0.5M Ω) or power supply voltage fluctuation (beyond ± 10%).
  • Magnetic pole gapThe magnetic pole spacing is too large (exceeding the design value by 20%) or the magnetic system is offset.
• process：
  • Permanent magnet demagnetization: Replace high-temperature resistant magnets (such as samarium cobalt magnets, with a Curie temperature of 350 ℃).
  • Electromagnetic repair: Rewind the coil (with the same wire diameter and number of turns as the original design), dry it, and then immerse it in paint for insulation.
  • Adjust the magnetic pole gap: Use a feeler gauge to check and ensure that the gap is uniform (error ≤ 0.1mm).

2. Magnetic medium blockage

• phenomenonThe processing capacity of the equipment decreases by more than 30%, or the magnetic content of the separated material fluctuates.
• reason：
  • The material has high viscosity (such as slurry in wet beneficiation) or excessively fine particle size (less than 0.045mm, accounting for more than 80%).
  • Failure of the blowback system (such as damage to the pulse valve, compressed air pressure<0.4MPa).
• process：
  • Cleaning magnetic media: Use high-pressure water (pressure ≥ 0.6MPa) or ultrasonic cleaning machine to remove blockages.
  • Optimize blowback parameters: Adjust blowback interval (10-30 seconds) and pressure (0.5-0.7 MPa).
  • Replace magnetic medium: Choose anti blocking type (such as gradient magnetic medium or mesh structure with an opening rate greater than 40%).

3、 Electrical control malfunction

1. Abnormal power supply

• phenomenonThe device is unable to start, frequently trips, or runs unstably.
• reason：
  • Voltage fluctuations (such as transient voltage drop>15% in mining power grid).
  • Contact erosion of the contactor (contact resistance>50m Ω) or misoperation of the thermal relay.
  • Electromagnetic coil grounding (insulation resistance to ground<0.5M Ω).
• process：
  • Install a voltage regulator (such as SVC-0.5kVA) or UPS power supply.
  • Replace the contactor (model should match the load current, such as CJX2-1210).
  • Repair coil grounding: After drying, repaint or replace the coil.

2. Sensor failure

• phenomenonAutomatic control system misoperation (such as false alarm, frequent start stop).
• reason：
  • Magnetic switch position offset (detection distance>5mm) or sensitivity decrease.
  • The temperature sensor is damaged (such as PT100 resistance deviation>± 0.5 ℃).
  • Misjudgment of level gauge (such as signal distortion caused by material adhesion).
• process：
  • Adjust sensor position: Ensure that the distance between the detection surface and the magnetic substance is ≤ 3mm.
  • Verify sensor accuracy: Use a standard source (such as Fluke 754) to test the temperature sensor.
  • Clean level gauge: Regularly blow the detection probe with compressed air.

4、 Operating environment malfunction

1. Influence of material characteristics

• phenomenonFluctuations in separation efficiency (such as a 10% decrease in magnetic recovery rate in wet beneficiation).
• reason：
  • Material humidity greater than 15% can cause adhesion (such as mud formation in coal washing).
  • Accelerated demagnetization of magnets with material temperature>80 ℃ (such as high-temperature slag treatment in steel plants).
  • The corrosiveness of materials (such as acidic wastewater in the chemical industry) erodes the surface of equipment.
• process：
  • Preprocessing materials: adding drying steps (such as hot air dryers) or adjusting pH values.
  • Choose materials that are resistant to high temperatures/corrosion, such as 316L stainless steel or ceramic coating.
  • Optimize equipment structure: Adopt counter current feeding method to reduce adhesion.

2. Dust pollution

• phenomenonShort circuit of electrical components, stuck bearings, or sensor malfunction.
• reason：
  • Dust concentration greater than 100mg/m ³ (such as in cement plants) leads to insulation degradation.
  • Dust seal failure (such as O-ring aging or improper installation).
• process：
  • Install dust cover: Choose an electrical box with IP65 protection level.
  • Regularly clean dust: Use a vacuum cleaner to clean the surface of equipment and ventilation openings every shift.
  • Replace seals: Use wear-resistant fluororubber (such as Viton material).

5、 Typical Industry Failure Cases

1. Mining industry

• faultThe drum bearings of the strong magnetic separator are frequently damaged.
• reasonFine magnetite particles (less than 0.038mm, accounting for 70%) in the slurry infiltrate the bearings, causing lubrication failure.
• processReplace with a combination of labyrinth seal and lip seal, and regularly (every 500 hours) change the lubricating grease (such as Mobil SHC 634).

2. Food industry

• faultElectromagnetic iron remover metal detector false alarm.
• reasonIron filings in flour adsorb onto the sensor surface, forming weak magnetic field interference.
• processAdd automatic cleaning devices (such as compressed air injection) and adjust detector sensitivity (increase threshold by 20%).

6、 Maintenance suggestions

1. routine inspection：
   • Record equipment operating parameters (such as current, temperature, processing capacity), draw trend charts to analyze anomalies.
   • Check the lubrication status and tension of the transmission components.
2. regular maintenance：
   • Detect magnetic force every 2000 hours (using a Gaussian meter to measure the magnetic field strength on the surface of the magnetic pole).
   • Replace bearing grease and seals every 5000 hours.
3. Spare Parts Management：
   • Reserve key spare parts (such as magnets, coils, sensors) to ensure that they can resume operation within 4 hours after a malfunction.