Variable frequency speed regulation can be used in most of the motor driving occasions. Because it can provide accurate speed control, it can easily control the rise, fall and variable speed operation of mechanical transmission. Frequency conversion application can greatly improve the efficiency of the process (speed change does not depend on the mechanical part), and it can save more energy than the original fixed speed motor. The following are ten reasons for the use of frequency conversion speed regulation to illustrate the basic understanding of the increasing popularity of frequency converter application:

1、 Control the starting current of the motor

When the motor is directly started by power frequency, it will produce 7 to 8 times of the rated current of the motor, which will greatly increase the electrical stress of the motor winding and generate heat, thus reducing the life of the motor. The variable frequency speed regulation can be started at zero speed and zero voltage (torque can be increased appropriately). Once the relationship between frequency and voltage is established, the inverter can drive the load to work according to V / f or vector control mode. The most direct benefit of the user is that the maintenance cost of the motor will be further reduced and the service life of the motor will be increased correspondingly.

2、 Reducing voltage fluctuation of power line

When the motor starts at power frequency, the voltage will fluctuate greatly while the current increases sharply. The extent of voltage drop depends on the power of the starting motor and the capacity of the distribution network. The voltage drop will lead to the fault trip or abnormal operation of voltage sensitive equipment in the same power supply network, such as PC, sensor, proximity switch and contactor. However, the voltage drop can be eliminated to the greatest extent due to the start-up at zero frequency and zero voltage.

3、 Lower power required at start-up

The power of the motor is directly proportional to the product of current and voltage, so the power consumed by the motor directly started by power frequency will be much higher than that required by variable frequency starting. In some cases, its distribution system has reached the highest limit, and the surge generated by the direct power frequency starting motor will have a serious impact on other users on the same network. If the frequency converter is used to start and stop the motor, there will be no similar problem.

4、 Controllable acceleration function

Variable frequency speed regulation can start at zero speed and accelerate uniformly according to the needs of users, and its acceleration curve can also be selected (linear acceleration, S-shaped acceleration or automatic acceleration). When starting by power frequency, the motor or the connected mechanical shaft or gear will produce severe vibration. This vibration will further aggravate the mechanical wear and loss and reduce the life of mechanical components and motors. In addition, variable frequency starting can also be used in similar filling lines to prevent the bottle from overturning or damage.

5、 Adjustable running speed

The application of frequency conversion speed regulation can optimize the process and change rapidly according to the process. It can also realize the speed change by remote control PLC or other controllers.

6、 Adjustable torque limit

Through the frequency control, the corresponding torque limit can be set to protect the machine from damage, thus ensuring the continuity of the process and the reliability of the product. The current frequency conversion technology makes not only the torque limit adjustable, but also the torque control accuracy can reach about 3% - 5%. In the power frequency state, the motor can only be controlled by detecting the current value or thermal protection, but can not set the precise torque value to act as in the frequency conversion control.

7、 Controlled stop mode

Just like controllable acceleration, in variable frequency speed regulation, stop mode can be controlled, and there are different stop modes to choose (deceleration parking, free parking, deceleration parking + DC braking). Similarly, it can reduce the impact on mechanical parts and motors, so as to make the whole system more reliable and the service life will be correspondingly increased.

8、 Energy saving

The energy consumption of centrifugal fan or water pump can be greatly reduced by using frequency converter, which has been reflected in more than ten years of engineering experience. Because the final energy consumption is set up square ratio with the motor speed, the investment return will be faster after using frequency conversion.

9、 Reversible operation control

In the inverter control, to achieve reversible operation control, no additional reversible control device is needed, only the phase sequence of output voltage can be changed, which can reduce maintenance costs and save installation space.

10、 Reduce mechanical transmission components

At present, vector control inverter and synchronous motor can achieve high-efficiency torque output, so as to save mechanical transmission components such as gearbox, and finally form direct frequency conversion transmission system. Thus, the cost and space can be reduced and the stability can be improved.