Localization of Russian Air Compressor Excitation System (1 PLA General Hospital Headquarters Beijing 100853, 2 AVIC: t Shenyang Dawn Aviation Engine (Group) Co., Ltd. Shenyang 110043) Economic Benefits and Safety Performance For enterprises currently using 4BM10 air compressor Can be introduced. Synchronous motors are important equipment in power systems and industrial production. The performance of their excitation devices directly affects the reliability and stability of synchronous motor operation. Synchronous motor excitation device control unit is mainly used for synchronous motor plus ball mill, gas compressor, fan, pump load, etc. for light or heavy load starting. It can control the excitation power of synchronous motor with the capacity of 125-10000KW. It can be used for three-phase full-control bridge rectifier circuit and three-phase half-control bridge rectifier circuit. When the synchronous motor is started at full pressure or step-down, when the speed reaches 94% synchronous speed (sub-synchronous speed), the centralized control unit automatically pushes the excitation by the amine slip of the excitation slip; Synchronous speed operation. The centralized control unit has a grid voltage compensation link, and the excitation voltage or the excitation current is kept constant by the action of the linear regulator. It has strong anti-drying ability. Once the grid voltage drops to 80%, it can automatically input the strong excitation link to ensure that the motor does not run out of step. The centralized control unit includes the de-excitation link and the out-of-step protection link to automatically de-excitation during the asynchronous start of the synchronous motor. For some reason, the out-of-step link in the centralized control unit causes the motor to be out of step protection when the motor is out of step. When the stator circuit of the motor is disconnected, the delay link in the centralized control unit causes the three-phase full control bridge to enter the inverter state to release the excitation winding energy of the motor, so that the thyristor component is not affected by the overvoltage. The centralized control unit adopts an integrated circuit; the circuits such as the regulator, the trigger circuit, the excitation excitation link and the DC power supply are concentrated on the same printed board, and have the advantages of simple structure and convenient debugging. After the stator of the synchronous motor is connected to the power supply voltage or the full-voltage start, it enters the asynchronous starting state, and the magnetic circuit is self-demagnetized by the de-excitation link. During this period, the circuit pulse is blocked, and the full-controlled rectifier bridge does not work. When the speed rises to a certain value, the motor is started by the slip to the full pressure by the full pressure. When the speed of the motor reaches the sub-synchronous speed, the trigger circuit opens the pulse to the thyristor control pole through the action of the excitation line. The bridge output DC voltage is applied to the excitation winding of the motor and the synchronous motor is pulled into the synchronous operation start. Changing the excitation reference allows the motor to operate at the required power factor. When the grid voltage changes, the voltage of the motor excitation winding terminal is kept constant by the action of the voltage compensation circuit and the regulator. When the stator voltage of the motor drops below 80%, the centralized control unit receives the strong excitation signal given by the high voltage cabinet, so that the excitation current (or voltage) of the motor rises. Once the voltage is restored, the system is restored to the original state. stable state. The strong excitation time is no more than 50 seconds. After the motor stator circuit is de-energized, due to the action of the delay circuit, the trigger circuit delays the blocking pulse. During this delay time, the three-phase full-control bridge enters the inverter disturbance state, so that the energy in the field winding is fed back to the grid, and the thyristor components are not protected. Voltage effect. The synchronous motor is out of step due to some factors. Once out of step, the motivation is to be a first-class modern research hospital. The sub-loop power factor is greatly reduced. After the delay, the out-of-step protection circuit gives a delay trip of the out-of-step trip signal to avoid malfunction and increase the reliability of the system operation. 1 Check that the high-voltage side main switch of the synchronous motor should be in the disconnected state. The universal transfer switch SA2 should be in the “0†position, and adjust the excitation adjustment knob W to the counterclockwise minimum position. 2 air switch QF power indicator light is on. 3-integrated control power switch SA1.4 turns the universal transfer switch SA2 to the “set†position. The fan running indicator lights up and the working wind direction is from bottom to top. 5 Slowly adjust the excitation adjustment knob clockwise until the excitation voltage and excitation current reach the rated value. 6 Press the de-excitation detection button. The excitation voltmeter reading is close to zero. The excitation current meter reading is unchanged. The release detection button excitation voltmeter reading is restored. 7 Separate the stator circuit isolating switch The universal transfer switch is turned to the “allow†position. The main switch face of the idler stator circuit checks whether the device enters the working state and the main switch is interlocked and opened, and the protection is normal. 8 After the above steps are completed, the test can be carried out. Through the above analysis, the modification of the excitation control system of the 4BM10 air compressor reaches the following requirements: il) Start of the synchronous motor When the synchronous motor starts, the demagnetization link is automatically put into operation. The alternating energy induced by the rotor of the motor is released by the de-excitation resistor to ensure the normal starting of the motor. When the synchronous motor does not reach the subsynchronous speed (with a slip of 0.05), the thyristor of the rectifier bridge is not pulsed. When the motor reaches the sub-synchronous speed, the output control unit outputs a pulse to the thyristor control pole, and the rectifier bridge conducts into the synchronous motor rotor winding and inputs the excitation synchronous motor into synchronous operation. 2 Synchronous motor synchronous operation The step-by-step motor is driven into synchronous operation and then controls the signal through the voltage (or current) feedback of the centralized control unit to ensure that the output voltage (or current) is unchanged during the power supply voltage fluctuation and other conditions. Constant excitation of the motor. 3 When the shutdown is normal or the shutdown is stopped, the centralized control unit will quickly trigger the trigger pulse control angle to the inverter angle. The rectifier bridge uses the maximum inverter voltage to quickly de-excitation the rotor's induction energy to ensure the synchronous motor is stopped by the de-excitation resistor release. 4 Over-current protection When an overload or short-circuit occurs, the air switch automatically zero bottle. When the DC side or thyristor is short-circuited and over-current, the jumper is quickly blown. The micro-switch sends an alarm signal to trip the main circuit of the stator circuit to stop the synchronous motor. 5 Over-voltage protection When the synchronous motor starts and loses step (asynchronous operation), the AC-induced over-voltage of the rotor is eliminated by the de-excitation resistor to eliminate the over-voltage (overvoltage caused by the switch breaking). The commutation overvoltage is achieved by the RC network connected to the thyristor and the absorption equalization protection is achieved by the resistor connected to the thyristor. In short, the localization of the excitation control system of 4BM10 air compressor solves the problems of aging components, cumbersome control, and difficult parts in the Russian excitation control system. The structure is reasonable and easy to replace, and the efficiency of the industrial automation is constant. Increasing the requirements for electrical equipment control systems will also be higher. We only have to continuously study and integrate more expertise to meet the needs of the rapid development of the industry. PP plastic, also known as polypropylene plastic, is another fine resin varieties, following the development of nylon, which is a semi-crystalline materials, the advantage is obvious, with excellent mechanical properties and heat resistance, with a high not hydrophilic sex, almost non-absorbent. The disadvantage is poor low temperature impact resistance, easier to aging. However, for comparison PE plastic having a higher melting point.
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Localization of Russian air compressor excitation system