With the development of power electronic technology, microelectronic technology and modern control theory, frequency converter has become the mainstream of electrical speed regulation and the main component of modern industrial control.
When VFD is applied to fluid machinery such as fans, pumps, and compressors, it can save energy; when applied to textile, chemical fiber, plastic, chemical and other industrial fields, it can improve the control performance, thereby improving the quality and quantity of its products; the application in the machinery industry can become a transformation Traditional industries, an important means to achieve mechatronics. Using a VFD to control the speed of an AC motor, frequency conversion technology has many advantages over traditional AC drive systems.
If the power is saved, a wide range of continuous speed regulation can be realized, and the speed regulation is more accurate. The motor is simple to rotate forward and reverse, and can perform high-intensity start-stop operations, electric braking, and high-speed motor drive. The most prominent is the perfect protection function of frequency conversion speed regulation.
The protection function of VFD is very strong. It can detect various faults in operation, display the fault category, and then block the output voltage immediately. While protecting the VFD, the motor is not easily damaged. Moreover, the main control part is executed by a single-chip microcomputer, which is small in size, low in price, strong in function, high in reliability, flexible and convenient. In general, the frequency conversion speed regulation constant pressure domestic fire water supply system has the following advantages:
(1) High efficiency and energy saving: the most significant advantage of the frequency conversion constant pressure water supply system is energy saving, usually 30% to 40% energy saving. From the perspective of energy saving of a single pump, the smaller the flow rate, the greater the energy saving. Special VFD for constant pressure water supply
(2) Constant pressure water supply: The system realizes the stability of the water supply pressure and the continuous change of the flow rate in a large range, so as to ensure the water pressure of the user at any time, and there will be no situation where the user has difficulty in using water during the peak water consumption period. In the event of a fire, the water pressure required for fire fighting will also be supplied to the fire pipe network.
(3) Safety and sanitation: After the closed-loop water supply system is implemented, all water used by users is directly supplied by pipelines, and facilities such as water towers, pools, and pressure tanks are eliminated, “secondary pollution” of water is avoided, and regular cleaning of pools is canceled.
(4) Automatic operation and convenient management: the new frequency conversion constant pressure water supply system has functions such as overcurrent, overvoltage, undervoltage, phase failure, short circuit protection, instantaneous power failure protection, stall protection, low liquid level protection, main pump timing rotation control, etc. . Automatic control, automatic operation, no post in the pump room, just send people to check and maintain regularly.
(5) Real-time monitoring: Use industrial control configuration software to monitor each station in real time, such as motor voltage, current, operating frequency, pressure, flow, etc. Unattended, saving manpower.
The constant pressure water supply VFD system can automatically adjust the system operating parameters according to the pressure change of the water supply pipe network, keep the water pressure constant, meet the water demand, and improve the fire safety factor of users on the other hand. It is an efficient, safe and energy-saving water supply system.
Since the 21st century, the frequency conversion speed regulation constant pressure water supply system has experienced a process of gradual improvement and development. The early single-pump constant pressure water supply system was gradually replaced by the multi-pump system. Today, the constant-pressure water supply system that combines life and fire protection has become a leading product with low investment and high operating efficiency. Since the advent of VFD, frequency conversion technology has been widely used in various fields.
The frequency conversion constant pressure water supply system realizes the soft start and stepless speed regulation of the pump motor, and automatically adjusts the system operating parameters according to the pressure change of the user’s pipe network. With the rapid development of power electronics technology, the functions of VFD are becoming more and more powerful. Taking full advantage of the built-in functions of VFDs can improve the design of water supply system equipment and reduce costs.
It is the main parameter that needs to be adjusted in the constant pressure water supply system. When the water consumption is low, the VFD controls the No. 1 pump to run at a certain speed; when the water consumption increases, the controller switches the No. 1 pump to power frequency operation, and controls the No. 2 pump to run at the speed of the VFD; When large, the controller and VFD switch pumps 2 and 3 in the same way.
When the water consumption decreases, the controller runs in the opposite direction. In this way, the system can meet the set requirements of the outlet pressure in the full displacement range. Different floors need to maintain different water pressure values. Both constant-running and variable-running motors have high efficiency, and the energy-saving effect is remarkable. The energy-saving rate is generally around 30% to 40%.
The three pumps share one frequency conversion device in time, and the equipment utilization rate is high. The three pumps can regularly rotate the main pump, which reduces mechanical wear, prolongs the service life of the equipment, and is easy to maintain.
