Schematic diagram of the excitation circuit system of the KGLF11 series synchronous motor thyristor excitation device: the control circuit of the original closing power supply cabinet is complicated, and the design and installation of the 380 volt three-phase half-control bridge line are unreasonable during use, which is easy to cause circuit failure. It is also not easy to repair.
Electrical schematic diagram of the closing power supply cabinet before the transformation: Since the closing current required for the DC closing power supply cabinet is relatively large, the contactor used for controlling the power supply has a large specification. When the SB1 or SB2 is pressed, the contactor KM will be powered, KM will close the contact of the main circuit of the AC power supply, and after the high-pressure oil switch QF is closed, its auxiliary contact will break the N to C2 control loop circuit, so that the contactor KM must be obtained during the whole starting process. The electric pull-in and the power-off are disconnected once, because the contactor KM is a larger contactor (CJO-75A; AC220V), and the vibration generated by the electric pull-in and the power-off break is large, and the high-voltage closing main circuit (- 220V30A) to DC control loop (-220V, 5A) example. If the selected components are not properly, the current and voltage output by the rectifier circuit can not meet the requirements of the high-voltage closing mechanism, which can cause the closing mechanism to operate not fast enough, so that the operating time of the high-pressure oil switch is prolonged, causing arc striking and damaging the touch of the high-pressure oil switch. head.
Two adjustable pressure relays (YWK-50, 0-1MP) for controlling the increase and unloading of the air compressor are located on the air compressor body. When the air technology is changed to the "automatic adjustment" state, such as air pressure When the secondary exhaust pressure of the machine reaches the critical value of the upper or lower limit set by the pressure regulator, the vibration of the air compressor is very high and the temperature is high, which easily causes the bimetal of the pressure regulator to open normally. Repeated action with the normally closed contact, and the relay that transfers its split and combined signals repeatedly receives power and loses power, causing the contacts of the relay to repeatedly operate, thereby causing two electromagnetics to control the air compressor to increase and unload the load. Repeated movements of cutting and related machinery, sometimes the frequency of movement can reach dozens of times per minute, it is easy to cause damage to related electrical and mechanical parts. Moreover, the damage of the unloading solenoid valve and related unloading components leads to the failure of the entire air compressor unit to be stopped at no load. If the load is often stopped, the air compressor unit will be mechanically damaged.
The control panel of the console is more prone to failure due to the large number of electronic control components and serious aging, and the original manufacturer is not reasonably installed. The original control instruments such as water pressure gauges, oil pressure gauges, first-class exhaust pressure gauges, etc., and these instruments are not easy to repair if they fail, or the repair time is longer. Some test instruments, such as sound and light alarms, temperature inspection instruments, etc., have been close to the end of life due to their long use time (12 years). The upper and lower limits of the original control instrument are adjusted by the adjustable potentiometer. The potentiometer is easy to aging and loose due to unintentional touch and improper use by the maintenance and operation personnel, which causes the parameters of the instrument to be inaccurate and distorted. In addition, due to the excitation current control line (DC 50V), the closing power control line (DC 220V), the air compressor oil pump power line (380V), etc., plus the high-voltage synchronous motor to increase and unload the relevant The disturbance generated by the circuit can also cause the related instrument to generate false alarms and malfunctions.
Solve the problematic methods and measures and compare the improved circuit with the original circuit. According to the characteristics of centralized air supply mode and high utilization rate of compressed air in the commercial vehicle base of Liuzhou Automobile Co., Ltd., after analysis and demonstration, the relevant transformation plan is formulated: (1) The new excitation device is purchased instead of the old excitation device. (2) Renovate the low-voltage control electrical components of the control cabinet and the low-voltage control circuit of the closing power control box, and redesign some of the circuits. (3) Improvement and replacement of other circuits and circuits.
Solution to the problem of aging KGLF-11-200/75 synchronous motor thyristor excitation device: purchase the new excitation device LCJ-2 (product of Wuxi Union Electronic Control Equipment Co., Ltd.) to replace the original excitation device.
LCJ-2 integrated circuit synchronous motor excitation device and KGLF200/75 can know the superiority of LCJ-2: KGLF11 series synchronous motor thyristor excitation device three-phase full control bridge rectifier circuit main circuit and LCJ-2 three-phase Looking at the main circuit of the full-control bridge rectifier circuit, the main circuit of the two devices is almost identical, and the ideal DC output voltage waveform of the load terminals of the two circuits is almost identical.
However, after the actual application, the pulse insert of the KGLF11 series synchronous motor thyristor excitation device is composed of six pulse inserts, and the pulse generation of each plug-in consists of a single junction transistor 2BG, a capacitor 1C, a triode 1BG, and a potentiometer. A charge and discharge circuit composed of components such as 4W and resistor 13R. The pulse amplification step consists of capacitor 2C, small thyristor 9KP and pulse transformer 1MB. Since the component parameters used in the pulse link are different, when the internal parameters of the components are excessively changed due to aging or the like, the phase of the output pulse of each phase is inconsistent, and sometimes the potentiometer 4W is adjusted to the head and the output pulse cannot be symmetric. However, many plug-ins may cause accidents such as poor contact due to manual insertion and removal, etc., so that the output waveform of the excitation device is poor or the rated voltage and current cannot reach the rated value.
After being improved to the LCJ-2 synchronous thyristor excitation device, the six-pulse forming unit of the LCJ-2 replaces the six pulse inserts in the KGLF11 series synchronous motor thyristor excitation device. The double pulse forming circuit is U12 (integrated circuit). 2003) and six OR gates U10, U11 and pulse transformers 1B to 6 components, due to the reliability and stability of the integrated components is much higher. Therefore, compared with KGLF11, LCJ-2 and 6KP six thyristor trigger poles can not trigger the conduction of the thyristor due to the trigger pulse of the trigger circuit, or the fault probability of the conduction characteristics is small. many. In addition: LCJ-2 synchronous thyristor excitation device control power supply, trigger phase shifting unit, phase-missing phase-under voltage monitoring unit, out-of-step protection unit and other circuits with integrated components as the core must be controllable than KGLF11 series synchronous motor The corresponding circuit of the silicon excitation device is more reliable.
The selection, design and arrangement of the internal components of the LCJ-2 synchronous thyristor excitation device are also quite reasonable. When any component (including thyristor) in the cabinet is damaged, the front and rear doors can be replaced within 30 minutes. The main components such as thyristor, trigger device, fast-melting, etc. all have fault protection loops, fault display lights and damage signs, which are easy to find fault points when a fault occurs. (For related pictures, please refer to Wuxi City Joint Electronic Control Equipment Co., Ltd. "Description of SCR Excitation Regulator").
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