Novel motor speed reduction protection device

Abstract

The invention discloses a novel motor speed reduction protection device, which includes a voltage detecting circuit, a logical judging circuit, a driving circuit, and a power circuit. When a motor pulls heavy objects beyond pulling capacity of the motor or a certain unexpected situations, the motor loses driving capacity, the heavy objects fall rapidly, speed reduction of the motor happens, and counter electromotive force generated by the fast revolving motor can rapidly elevate the bus voltage of a controller; the voltage detecting circuit detects the bus voltage, and then transmits the bus voltage to the logical judging circuit to conduct calculation and judgement; when protection actions need to be adopted, signals are transmitted to the driving circuit, the driving circuit prompts a switch K to act, and the connection between the motor and the controller is cut off; and meanwhile the motor and a discharging circuit are connected, braking force is generated by the motor, acceleratedspeeds of the falling heavy objects are lowered greatly, and damage is further reduced.

Description

technical field [0001] The invention relates to a novel motor protection device, in particular to a stall protection device for a lifting motor. Background technique [0002] In some applications, the motor controller needs to drive the permanent magnet synchronous motor to lift the goods up and down, such as elevators, cranes, etc. The goods are usually connected to the motor by belts, steel belts, etc. Since the goods themselves are heavy, in order to reduce the size of the motor Therefore, a balance weight is needed to balance and hang on the other side of the motor, and the motor only needs to overcome the difference between the two weights to do work. The typical application is an elevator. The counterweight of the elevator is the weight of the car plus half of the rated load, so the maximum output of the motor is only half of the rated load. The reliability of the motor control determines the controllability and safety of the elevator. The safety level of the entire sy...

AI Technical Summary

Problems solved by technology

[0003] Stall refers to the abnormal increase of motor speed under the influence of non-external force, which leads to an unstable state of the system

For example, when any section of the rope breaks due to some accident, the motor will not be able to bear the weight of the heavy object at the other end, and the heavy object at the other end will fall rapidly. At this time, the motor will be dragged to a high speed, and the back electromotive force of the motor will quickly When the withstand voltage of the driver is exceeded, the driver will be permanently damaged, so the motor stall will pose a great threat to the safety of the system

[0004] The motor stall protection device in the prior art usually uses a speed sensor to sense the motor speed, so as to judge whether the motor is in a stall state. The speed sensor is expensive, which leads to a sharp increase in the cost of the motor stall protection device. quite complicated

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