Abstract: This article describes the transformation of WKS series inverters developed by Welke Electric (Shanghai) Co., Ltd. in the screw air compressor and the energy saving effect achieved. Before the equipment transformation, every two air compressors are used one by one and all equipment is working in the power frequency state. The starting method is star-delta step-down starting, and the pressure control adopts two-point control (upper and lower limit control), ie the air compressor cylinder. When the internal pressure reaches the set upper limit, the air compressor closes the air lock by its own hydraulic pressure. When the pressure drops to the set lower limit, the air compressor opens the intake valve. Due to the changes in the amount of gas used in the production process, the air compressor is frequently loaded and unloaded, the starting current of the main motor is still large, affecting the stability of the power grid and the safety of other electrical equipment, and the impact of the motor power frequency starting equipment is high. The wear of the motor bearings is large, so the amount of machinery is large during maintenance work. The main motor does not generate compressed air during frequent no-load operation. It is a non-economic operation, a serious waste of electrical energy, and the noise of the motor when the power frequency is running causes the compressor to run very noisy. Therefore, it is necessary to carry out frequency conversion transformation of the main motor. . Fourth, system principle design scheme The frequency conversion control system is made up of the following part: The frequency changer, the frequency conversion cabinet, the reactor, the pressure transmitter, the exchange contactor, the intermediate relay and so on are composed, the frequency conversion control cabinet function includes: Starts, runs, stops, switches, Alarms and other control functions. WKS series inverter adopts advanced control technology, according to the user's compressed air demand, without changing the original control system circuit, using pressure sensing technology to detect the pressure of the network, so that the compressor motor stops running at no-load operation. According to the air volume, the air pressure is automatically adjusted to ensure that the air compressor is always running in the energy-saving state, which can save electricity and save energy. V. Investment Analysis Audible and visual alarm is set up to meet customers' special requirements for alarm loudness and installation location. At the same time, two alarm signals, sound and light, are issued. Special fields: iron and steel metallurgy, telecommunication towers, hoisting machinery, construction machinery, ports, transportation, wind power generation, ocean-going ships and other industries; it is an accessory product in the industrial alarm system. emergency alarm,Audible Visual Signals,Visual Alarm devices,sound and light siren,visual alarm system Taixing Minsheng Electronic Co.,Ltd. , https://www.msloudspeaker.com
Keywords: air compressor inverter WKS
Abstract: This paper introduces Wer Kai Electric (Shanghai) Co., Ltd. R & D production WKS Series Frequency transformation in the content of screw air compressor, and to achieve the energy saving effect.
Key words: Air compressor Inverter WKS
I. INTRODUCTION An air compressor is a device that uses a motor to compress a gas in a compression chamber and causes the compressed gas to have a certain pressure. As basic industrial equipment, air compressors have been widely used in almost all industrial industries such as metallurgy, machinery manufacturing, mining, power, textiles, petrochemicals, and textiles. Air compressors account for 15% of the power consumption of large industrial equipment (fans, pumps, boilers, air compressors, etc.). Due to structural reasons, most air compressors have obvious technical weaknesses.
With the establishment of Welke Electric (Shanghai) Co., Ltd. in China, the application of WKS series inverters in the field of speed regulation has become more and more extensive. It has the advantages of stable operation, convenient operation, and obvious energy-saving effect. It is increasingly valued by the majority of engineering and technical personnel and management personnel. The vast majority of production equipment uses compressed air, which was previously supplied by a single small air compressor. This type of air supply has the disadvantages of unstable pressure, high failure rate, and large maintenance costs.
II. Operational status before and after air compressor rebuilding Germany Standard Pipe (Shanghai) Co., Ltd. has a total of 5 screw air compressors. The specific parameters of the air compressor are as follows:
Equipment Name Quantity Power Speed ​​Speed ​​Operating Pressure Remarks Screw Air Compressor 5 90KW 2900r/min 6.5kg-7.8kg Instability Total 2 90KW Now Renovation Two sets
The current operating conditions are: no-load voltage: 405V current: 116A; operating voltage: 411V current: 185A; visual power power for no-load work: 48KW working power: 132KW; no-load active power: 47KW active power: 115KW The compressor power is 90KW and the speed is 2900 rpm. At present, the upper limit of the output pressure of the air compressor is set at: 7.8kg, the lower limit pressure is set at: 6.5kg The average working pressure is at 7.0kg, and constant pressure air supply is realized.
Third, the principle of energy conversion Volcker The basic operating mode screw air compressor loading, load reduction. When the load is idle, the motor runs idle and the energy is wasted. If the WKS series inverter is used to adjust the speed by changing the motor frequency, the frequency conversion control will change the speed of the motor to control the air output per unit time of the air compressor so as to achieve the control pipeline. Pressure, with significant energy savings. Air compressor frequency conversion energy-saving system principle: through the pressure transmitter measured pipe network pressure value and the pressure set value compared to get the deviation, the PID regulator to calculate the frequency converter in the asynchronous motor frequency value. The corresponding frequency and amplitude of the alternating current output by the WKS frequency converter is commensurate with the motor speed. Then the air compressor outputs the corresponding compressed air output to the air tank, so that the pressure changes until the pipe network pressure is the same as the given pressure value. Inverter, pressure transmitter, motor, screw rotor pressure closed-loop control system automatically adjusts the motor speed, so that the air pressure in the air tank is stable within the set range, constant pressure control. The feedback pressure is compared with the set pressure, and the output frequency of the inverter is controlled in real time so as to adjust the motor rotation speed so that the air pressure in the air tank is stabilized at the set pressure.
When the system is reformed, the original power frequency system remains unchanged. Only the Volkley frequency conversion control system is needed. No need to retrain the operating personnel. When the air compressor control system is running, the frequency conversion system automatically enters the running state. The system adopts a pressure closed-loop regulation method, set the air pressure constant value through the control panel of the inverter, and install a pressure sensor on the gas storage tank. The air pressure signal is converted into an electrical signal from 0 to 10 V and fed back to the PID regulator inside the inverter. The regulator compares the signal with the pressure setting value, and then outputs the control signal. The inverter then outputs the frequency according to this signal. The speed of the motor is adjusted so that the air pressure is kept stable, so that the air compressor is always kept in a power-saving operation state.
System operation steps:
(1) Select frequency conversion/power frequency startup before starting up;
(2), start the "start" button of the air compressor, the inverter starts within the set time, and the air compressor starts to work;
(3). The frequency converter performs the comparison according to the pressure of the on-site pressure transmitter to detect the outlet pressure of the network management. After the PID instruction calculation, the frequency converter output frequency is adjusted;
(4) Stop the air compressor, stop the air compressor and the inverter at the same time;
1. Name of investment equipment Power (KW) Inverter model and brand Quantity (sets) Unit price (RMB) Total price (RMB)
Spiral Anhydrous Air Compressor 90 Welke WKS110G4TC 1 45347.00 45347.00
Installation and commissioning 10% 4534.00
Taxes 8% 3627.00
Total 53508.00
In all,
2. The investment recovery period is calculated by taking one of the two sets of transformations in your company as an example: the power is 110KW, the total investment is 53508.00 yuan, the company's operating condition is 24 hours per day, the load rate is 0.87, and the electricity fee is 0.8 yuan/ Degree, 30 days per month, saving 20% ​​of the energy then:
Monthly Electricity Price = Total Power × Load Rate × Monthly Operating Time × Electricity Price × Electricity Saving Rate
=90×0.87×24×30×0.8×20%
= 9020 (yuan)
New Year's Day Electricity = Monthly Electricity * 12 months
=9020×12
=108240 (yuan)
Payback period = total investment ÷ monthly electricity fee
=53508÷9020 6 (months)
This shows that it takes about six months to recover the investment.
Sixth, several major advantages after the transformation (1), energy saving.
(2) The motor starts from a low speed, the inrush current is small, and the motor and the air compressor operate stably.
(3) As the inverter has a strong protection function, the failure rate of the equipment is reduced.
(4) System pressure is more stable and product quality is improved. (5) To a great extent, the work intensity of the company's electrical engineers was reduced.
7. Concluding remarks After using the Wilcox WKS series inverter to carry out the energy-saving renovation of the two sets of air compressors, after more than one year of actual operation, the company is working normally, the pressure is stable, and the energy saving effect is significant, making the company's high house managers see the energy saving. The effect, thereby greatly reducing the company's electricity bills! 