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Frequency conversion speed control system has been widely used in the industrial production of various small and medium-sized enterprises. This is due to the fact that we can provide accurate speed control and achieve stepless speed regulation. Therefore, it can easily control the mechanical transmission of the rise, fall, transverse movement and other operating actions, improve the efficiency of the process (variable speed does not depend on the mechanical part), than the traditional uniform speed running motor more energy saving. Here are 10 reasons to use frequency control in production activities:

(1) Control the starting current of the motor to achieve soft start.
When the motor is started directly with power frequency, the starting current is 4 to 7 times the rated current of the motor. Excessive current will increase the electrical stress of the motor windings and generate heat, thus shortening the life of the motor. The frequency converter (hereinafter referred to as -VFD) uses frequency conversion speed regulation technology, which can drive the load according to V/F or vector control. The use of frequency conversion speed regulation can fully reduce the starting current, improve the bearing capacity of winding, reduce the impact of mechanical equipment, failure rate and equipment maintenance costs.

(2) Reduce power grid voltage fluctuations and power grid pollution.
When the motor is started at power frequency, the current will increase sharply, and the voltage will fluctuate greatly. The size of the voltage drop will depend on the power of the starter motor and the capacity of the distribution network. Voltage drop can cause voltage sensitive devices in the same power supply network to trip or work abnormally, such as PCS, sensors, proximity switches, contactors, etc. However, after the adoption of variable frequency drive scheme, because it can be started step by step at zero frequency and zero voltage, the fluctuation of power grid voltage can be eliminated to a large extent.

(3) The power required for start-up is low, which reduces the capacity requirements of the grid.
The power of the motor is proportional to the product of current and voltage, so the power consumed by the motor started directly with power frequency will be much higher than the power required for frequency conversion. Under some conditions, its distribution system has reached the excellent limit, and the surge generated by its direct power frequency starter motor will have a serious impact on other users in the same network, and will be warned or even fined by the grid operator. If the VFD is used to start and stop the motor, such problems can be improved.

(4) Controllable acceleration function to improve equipment working conditions.
Variable frequency speed regulation can start from zero speed, accelerate evenly according to user needs, and its acceleration curve can also be selected (linear acceleration, S-shaped acceleration or automatic acceleration). If the shaft or gear of the motor or the connected mechanical part will vibrate violently at the power frequency, this vibration will further aggravate the mechanical wear and loss, and reduce the service life of the mechanical part and the motor.

(5) The running speed can be adjusted to improve product quality.
The frequency conversion speed regulation scheme can optimize the process flow and can change quickly according to the process flow. Intelligent speed control can also be achieved by remote control PLC or other controllers to achieve optimized machining results.

(6) Adjustable torque limit to provide equipment protection.
After frequency conversion speed regulation, the corresponding torque limit can be set to protect the machinery from damage, so as to ensure the continuity of the process and the reliability of the product. At present, the frequency conversion technology not only makes 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 the thermal protection device, and the accurate torque value cannot be set like the frequency conversion control.

(7) Controllable shutdown mode to achieve precise control.
Just like controlled acceleration, in variable frequency speed regulation, you can control the stopping mode, and there are different stopping modes to choose from (slow down stop, free stop, slow down stop +DC brake). Similarly, it can reduce the impact on mechanical components and motors, thus making the entire system more reliable and correspondingly extending its service life.

(8) Reduce energy consumption and achieve energy-saving operation.
The use of VFDS for secondary loads such as centrifugal fans or pumps can greatly reduce energy consumption, which has been reflected in more than ten years of engineering experience. Because the final energy consumption is the square ratio of the motor speed, the return on investment will be faster after conversion. 

(9) The operation direction of the equipment is reversible, and it is easy to achieve positive and negative operation.
In VFD control, reversible operation control is realized, and no additional reversible control devices are required, only the phase sequence of output voltage needs to be changed, which can reduce maintenance costs and save installation space.
 

(10) Reduce mechanical transmission components and optimize system structure.At present, the old drive motor of vector control inverter can achieve high efficiency torque output, thus eliminating mechanical transmission components such as gearbox, and finally forming a direct frequency conversion transmission system.