Mag drive coupling in coal mill
The mag drive coupling is used in a company’s coal mill project, which completely solves the long-standing problem of the company’s coal mill squirrel cage breakage. The company has 2 sets of 200MW units, using angle-type pulverized coal burners, equipped with 6 fan coal mills (4 running, 2 standby), and the coal mill is equipped with a motor power of 800KW.
The company found that the squirrel cage was broken during the maintenance of the coal mill motor. Preliminary analysis showed that due to the heavy impeller (23T), large inertia, large starting torque, and large current (450-700A), the starting speed climbed for a long time (60S). , during the start-up period, the motor squirrel cage bar flows through a large induced current and heats up quickly, and breaks under the action of the starting torque shear force and the heating stress of the through bar. To solve this problem, the company opened a tender for a solution.
Due to the high power of the motor, the weight of the impeller is heavy, the starting torque is large, and the speed is low. Faced with such a situation, many companies are unable to propose solutions that can fundamentally solve the problem. In the end, we have strong R&D capabilities and advanced production capabilities. In the end, the project was successfully bid with the mag drive coupling scheme.
Solve the problem of starting overload: It is planned to transform a coal mill for soft start, using a composite three-disc mag drive coupling to replace the original rigid nylon pin coupling, and combining the existing installation space, design the outer diameter of the mag drive coupling size, the foundation is not changed, the position of the motor is unchanged, and the permanent magnet coupling is installed between the motor and the bearing box of the coal mill to realize the light-load start of the motor.
Working principle of mag drive coupling
The mag drive coupling is an enhanced version of the conventional permanent magnet coupling. Its working principle is the same, and it can meet the transmission requirements of high-power equipment.