1. The No.1 belt conveyor of Majialiang Coal Preparation Plant of Datong Coal Mine Group suffered from severe vibration. To solve the vibration problem, a WF-CT550280 permanent magnetic coupler was installed on the belt conveyor. The installation was completed from November 3 to 5, 2020, and the equipment has been in operation ever since. The vibration value is less than 2.4mm/S with stable operation and remarkable effect. The relevant experience is summarized as follows.

II. Equipment Description of Permanent Magnetic Coupler

1.Equipment Model: CT550280;

2.Installation Type: Horizontal Installation;

3.Functional Features: Torque-limiting type;

4.Usage Location: No.1 Belt Conveyor

5.Motor Parameters: 250kW/1480rpm

III. Installation Description

1.Reserve a spacing of 200mm between the shaft ends of the motor and reducer during design;

2.The installation is similar to that of installing a coupling;

3.It is required to check the gaps on both sides, which shall be uniform and both 3.172mm with a tolerance not exceeding 0.5mm.

4.Installation Legend

IV. Commissioning Operation Status

1.After startup, the motor and the connected conductor disc quickly reach the rated speed of the motor. The rotating speed of the permanent magnet connected to the load gradually increases and finally stabilizes at a constant speed, completing the starting process.

2.Smooth operation with extremely low vibration;

3.The speed of the load is 2% slightly lower than that of the motor.

V. Usage and Maintenance

1.Adaptable to various harsh environments, unaffected by dust, temperature, mud and water;

2.No bearings or other wearing parts are required, and no maintenance is needed as with coupling products.

VI. Overload Protection

1.The torque-limited permanent magnet coupler can realize the overload protection function during operation. When the load is suddenly overloaded or locked, it can quickly increase the gap between the magnetic disc and the conductor disc, cutting off the torque transmission between the motor and the load. This allows the motor to run unloaded and protects the motor.

2.None of the above situations have occurred so far.

3.Such experiments will be conducted in the future to verify the performance.

VII. Safety and Stability

1.The buffered soft start reduces impact on the power grid and equipment, and lessens tension fluctuation during the startup of the belt conveyor.

2.It reduces the impact on mechanical equipment, belts and joints;

3.Low starting current, which is beneficial to the motor;

4.The torque-limiting overload protection function can effectively protect rotating components such as motors, loads, shafts and bearings;

5.After the motor stops, the permanent magnet coupler can reset automatically and be restarted immediately without any time delay, making it more reliable than fluid couplings.

VIII. Advantages of Torque-Limited Permanent Magnet Coupler

1.Buffered Soft Start: Reduces the inrush current of the motor and extends the service life of equipment.

2.Torque Limiting and Automatic Stall Protection: When the load is overloaded, the air gap between the conductor disc and the permanent magnet disc will automatically enlarge, enabling the motor to operate under light load or no load without stalling, thus protecting the motor.

3.Tolerates large installation alignment errors: greatly simplifies the installation and commissioning process.

4.Overload Protection Function: It enhances the reliability of the entire motor drive system.

5.Low Maintenance: Simple structure with minimal maintenance requirements.

6.Low Maintenance: Simple structure with minimal maintenance requirements.

7.Excellent vibration damping effect: Torque transmission without mechanical connection.

8.Simple structure: adaptable to various harsh environments, produces no pollutants and complies with green product standards.

9.It has a certain energy-saving effect: it reduces the starting inrush current, with an energy-saving effect of 5%-20%.

10.No harmonics are generated.