the configuration and fixed value setting of motor overload protection

23 Sep 2021249

1 The causes and harms of the three-phase asynchronous population's rapid decline

There are many reasons for the overload of the three-phase asynchronous load: one is the actual load increase, such as the load causes the service to be overloaded, or the equipment and other equipment cause the load to increase; the second is the abnormal load, the excessive birthday current, voltage, and frequency decrease, etc. a long time. The main feature is outdated and will cause sudden bursts, injuries, and injuries.


   2 Multiple three-phase asynchronous generators generating overload protection configuration and fixed value setting

For the time when overload is prone to occur during operation, the protection should meet the load characteristics, with a time limit action signal or trip; for startup or self-start faults, it is necessary to avoid excessive start or self-start time, and the protection action is tripped.

At present, for minority groups, the general protection configuration is usually long protection, blocking time transfer protection, and overload protection. Time limit, the current action set value is 1.5-~2.0 times the time current, the action time starts according to the normal time of the escape time, and the action is tripped. The action setting value is 1.3~2.0 times the starting time of the action current, and the action time is started according to the hidden time or self-tuning time, and the action is tripped.


   3 Three-phase asynchronous stator peak overload protection configuration and setting suggestions

3.1 Full consideration should be given to the characteristics of the responsibility burden and its position in the system, and the overload protection shall be configured according to the two-stage principle.

Full consideration should be given to the load characteristics and the state in the system. The overload protection for important personnel is configured in sections and protected by signals to remind the operators that the other section of the protection outlet will trip. To ensure the safety of personnel, try to release the idle overload capacity, delay the tripping time of another protection outlet, and give the operating personnel time


3.2 Optimize the over-load protection logic and set the sub-brightness criterion

In order to ensure the safety of the battery, the current-type battery overload protection can be introduced into the battery temperature auxiliary criterion.

3.3 Configure the overload heating value protection and set the protection reasonably

Micro-fatigue comprehensive protection is equipped with constant load thermal overload protection. The overload protection model comprehensively considers the different influences of the negative current of the motor on the current and current, as well as the motor's cold, hot, and heat dissipation conditions. The thermal upper limit curve or overload capacity of the battery provided by the labor insurance manufacturer, reasonable setting and operation of the appropriate thermal overload protection value, is an effective and effective way to protect the battery from overload.

Concluding remarks


For the important overload protection of employees, full consideration should be given to assuming responsibility, fully releasing the capacity to bear the overload, and setting the capacity to bear the overload. Remind the operating personnel to adjust in time; the other stage of action is tripping, and the fixed point of the tripping section is adjusted according to the hidden value overload capacity. At the same time, the standby generator can be used as an auxiliary judgment for standby overload, and the trip can be initiated when the conditions are met. And reasonable setting of timing thermal overload protection is an effective means to protect against excessive load.