The understanding of the three-phase asynchronous motor

Resection of the three-phase asynchronous motor power rely on inertia and rotation for a period of time (or distance) to stop, and a hook or hoist crane in the production of hanging basket require accurate positioning; Universal milling machine spindle requirements can quickly stop; Elevator after a sudden blackout need security protection and accurate positioning control... And so on. All of perkins diesel generator these need to drag brake motor, the so-called braking, is to give a torque and rotation in the opposite direction of the motor to make it quickly halt or limits its speed. Braking method generally has two kinds: mechanical braking and electrical braking. (a) mechanical brake Use machinery to make motor www.facebook.com/dongfeng.motor stalling method is called immediately after the power off mechanical brake. The commonly used methods: electromagnetic brake braking. 

1, the structure of the electromagnetic brake: Is mainly composed of two parts: brake electromagnet brake and brake shoe. Brake electromagnet by core, coil and armature of three parts. Brake shoe brake including brake drum, brake shoe, and spring etc, brake wheel and motor installed on the same axis. 

2, how it works: motor power, and electromagnetic brake coil electricity, armature and, to overcome the tension of the spring brake shoe and brake wheel, motor function. Disconnect switch or contactor, motor power, electromagnetic brake coil also lost electricity at the same time, the armature to separate from the core, under the action of a spring tension and make brake shoe hug brake wheel, motor is braking and halt. 

3, the characteristics of the electromagnetic brake braking Mechanical brake mainly adopts the electromagnetic brake, electromagnetic clutch brake, both magnetic field generated by electromagnetic coil after electrify make the static iron core produces enough suction and armature or moving iron core (electromagnetic clutch of moving iron core is sucked, dynamic and static friction piece separately), to overcome the tension of the spring and meet the requirements of the job site. Electromagnetic brake is to rely on the  electric fan motor parts brake shoe friction disc brake wheel. Electromagnetic clutch is the use of dynamic and static friction piece immediately when the power is enough friction between motor brake. Advantages: electromagnetic brake braking, braking force is strong, widely used in lifting equipment. It is safe and reliable, won't because suddenly loses power and accident. Weakness: the electromagnetic brake volume is larger, brake wear serious, rapid brake vibration can be created. 

4, motor brake clearance adjustment method 1) downtime. (mechanical and electrical close confirmation, pressure and power locks, and hung "is maintenance", "it is forbidden to start them.) (2) remove fan cover; (3) remove the fan circlip, remove fan blade; (4) check the residual thickness of the brake lining (minimum thickness of brake lining). (5) to check if the protective plate: protective plate edge has touched the dowel pin marks, must replace the brake disc; 6. Adjust the air brake clearance: three (four) to tighten bolts to the air gap is zero, then reverse loosen bolts Angle is 120 °, with feeler check the brake clearance (check at least three points), should be uniform and conform to the specified value; Please reset is wrong. (note: the brake model is different, its reverse unscrew Angle, the brake clearance is different). All landowners manual operation, brake action sound is ringing, stop position accurate and effective. Today the scene 6 s standard cleaning.