Tag: vfd

The VFD speed control system regards the network pressure as the control object. The pressure transmitter changes the pressure in the air storage tank into the electrical signal to send into the PID regulator inside the VFD, so as to compare with the pressure setting value. Then calculation will be made according to the set PID control mode based on the difference value. The control signal will be generated to control the output signal and inverter frequency of the VFD, thus adjusting the revolving speed of the induction motor, so as to maintain the practical pressure to be always as the setting pressure.

According to the manufacturing technology of the hydroextractor, the multi-speed functional control of the VFD can be used. The hydroextractor with VFD control system belongs to the approximate constant torque load with big inertia. Therefore, the system requirements can be reached by configuring braking unit and braking resistor on the basis of selecting the AC converter. The built-in braking unit of the30hp VFD and below can not only save space, but also save the cost.

This article ATO summarizes how to apply and debug the VFD for the circular knitting machine in one textile mill. ATO chooses the non-inductive vector VFD. It adopts current vector control, its precise control as well as the characteristics of low-frequency stability and large torque, realizing the functions of big starting torque, stable operation, quick stop and so on of the circular knitting machine.

The working principle of the automatic industrial washing machine is: under the unified deployment and management of the time schedule controller. The VFD controls the induction motor to carry out positive and negative revolving uninterruptedly, thus achieving the non-synchronous movement of the water and the clothes, so as to enable the water and the clothes to rub and knead, thus being cleaned.

For a long period, the chemical, cement, ceramic industries and so on normally adopt the ball mill to grind the raw materials. Usually, the decompression start-up mode is employed. The high starting current has great shocks to the equipment and power grid. Meanwhile, in working frequency, it is easily to over grid the materials. The required grinding circle is long, with low grinding efficiency and high unit product consumption. This promotes people to study and develop the ball mill system with smooth start, high grinding efficiency, high output and low consumption. This is exactly the VFD control system.

The turning rolls are the devices, which drive the cylinder-shaped (or cone-shaped) weldment to rotate with the help of the friction force between the weldment and the driving rollers. The self-aligning turning rolls are suitable for welding the round cylinder. It can regulate by itself according to the size of the cylinder. There are several specifications for the customer to choose. The self-aligning turning rolls include two groups of main and vice devices for one set, which means to four wheels for each device: self-aligning active turning rolls and self-aligning passive turning rolls. The wheel is fabricated in the inner iron core and outer rubber structure. Therefore, it is durable in use, free of any vibration. The operation of the active turning rolls is synchronously driven by the speed regulating motor through two worm gear reduction box. Thus, turing rulls can realize stepless speed variating by using ATO VFD.

Using VFD for speed regulating has many advantages. Many small power motors adopt single phase power supply. How to use VFD to regulate speed for single phase motors? ATO will provide the following methods.

The wire drawing machine is one of the main equipment of the metal wire processing as well as the cable and wire industry. It is mainly used to process the metal wires into the fine lines of various specifications. It usually constitutes the paying off, water cooling, winding up, winding displacement and other components. Its electric drive part is mainly realized by paying-off motor, winding-up motor and winding displacement motor. The wire drawing machine belongs to the constant-torque load. Its characteristics require that the VFD has a big start-up torque and can satisfy the full-load output in low speed. Meanwhile, it requires realizing the coordinated control of several motors in high precision percentage.

When the roots blower has went through improvement by VFD, the system can realize soft starting and soft stopping, so as to reduce the shock of the system to the power grid in start-up, thus reducing the system start-up times and ensuring a stable operation. What's more, because of the deceleration of the revolving speed in roots blower operation, it can reduce the mechanical wear and prolong the operating life of both the motor and the roots blower. If the system employs pressure closed-loop control improvement, the fully automatic control and unattended operation can be realized.

In recent years, as the increasing drastic market competition and the improving of the electromechanical integration technology in textile machinery, the textile machines at home and abroad generally enter into the era of frequency control and drive. The frequency control of the speed regulating replaces the traditional machine structure. It has been widely adopted to the shuttleless loom and basic textile equipment, such as blowing, cotton carding, lap forming, roving, spinning, spooling, warping, slashing, and the other main technological processes. What is more, the newly developed textile machines have adopted VFD to control motor speed without an exception, which has greatly improved the reliability of the textile machine, textile quality and automation degree.

Here ATO will take the application of high-performance vector VFD in a CNC machine factory as an example, to discuss about the frequency conversion control technique of CNC machine.

The advantages of VFD controls plastic extrusion machine

1. VFD controls the driving motor of the main engine and auxiliary engine, satisfy the required revolving speed and power of the process, make sure that the main engine and auxiliary engine can operate coordinately. ATO VFD realize the automatic control of the whole unit, ensure good quality and high yield.
2. Realize remote control, fine adjustment of the speed.

The variable frequency drive has the following ten protections on the motor:
Over-voltage protection: The variable frequency drive output has automatic voltage regulator function to control the external overtop power input to be not exceed the motor rated voltage.

If you want to connect a 3-phase motor to a single phase power supply, then you have several solutions:
1) use a VFD with a single phase input and convert to 3-phase output, this is generally available for low power VFD (few horsepower).
2) apply a specially wound transformer that also mimic a 3-phase system from a single phase power supply. Expect difficulties to source and high price.
3) calculate a capacitor that will be connected between the remaining phases, such to apply it a phase shift and to mimic a 3-phase system.