4.—Is there any danger in starting Tun Liu? Why do some induction motors need a starting device?
Answer: It is said that since the starting process is not long, a large current flows in a short time, and the heat is not too harmful. The motor can withstand it, but if it is normal
The starting conditions are destroyed, for example, the motor specified for light load start is used for on-board start, and the speed cannot be increased normally, or when the voltage is low, the motor reaches the motor for a long time.
Less than the rated speed, and the motor starts multiple times in a row, it will likely cause the motor windings to overheat and burn.
The large starting current of the motor has an impact on other electrical equipment on the same power supply line of Jingren. These four fires supply a large starting current to the motor,
The electric power of the power supply line has dropped greatly, resulting in a great reduction in the electric power of the busbar connected to the motor, and the normal operation of other electrical equipment, such as the light is not on,
Its dead motor cannot be started, and the electromagnet is automatically released, etc.:
As far as the induction motor is concerned, it is allowed to start directly, that is, it can be started with rated voltage.
Because the capacity of the hand motor does not match the capacity of the power supply it is connected to, the induction motor may be too low due to the line terminal voltage drop when starting.
The starting torque is not enough to start. In order to solve this problem and reduce the impact on other electrical equipment with the same bus, some power plants with large capacity
The motive must use a starting device to limit the starting current and its effects.
The report committee does not 5 to start the equipment, the key lies in the comparison of the power supply capacity and the size of the motor capacity. The power plant or power grid has a large sense of capacity, allowing direct start-up
The moving motor capacity is also larger. Therefore, in the newly built medium and large electric buildings, almost all induction motors except the winding type are directly started.
Only in the old and small power plants, you can still see various motors with various starting devices.
For rival squirrel cage motors, the purpose of adopting the starting device is nothing more than to reduce the starting current, so as to reduce the starting current. while root
Depending on the step-down method, the start-up method (1) Y/厶 conversion start-up method. During normal operation, the winding is connected to a male motor, and it is connected to
Yahua, it will be changed to what shape connection method after it is started. (2) Start the method with self-conscious change of musical instruments. <3) Start method with reactor.
