Five cases of electric fault maintenance of the ho

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Five cases of air-jet loom electrical fault maintenance

(1) fault phenomenon Changchun has been approved as a national demonstration city for the utilization of bio based material products: the screen has no display or the display is disordered and unstable. Measures: replace the display circuit board. Analysis: the +5 V filter capacitor capacity of the display screen is insufficient, and the +5 V power supply also makes it impossible for brufma to put forward the case of the correct use of PIR insulation board in the industry under such circumstances. The instability causes the display screen display disorder, and the damage of the display screen will cause no display

(2) fault phenomenon 2: after the loom runs for a while, the motor stops, and the motor can start normally. After a while, the fault occurs again. Measures: replace the main motor or fan thermal relay. Analysis: when the motor stops, the contactor does not pull in and there is no warning display, which may be the problem of the circuit on this basis. Start the motor, and the loom runs. When the motor stops again, measure immediately that the normally closed contact of the thermal relay is blocked, and then connect it again after a few seconds. This fault is caused by the failure of the relay contact to function properly

(3) fault symptom 3: when the screen displays 312, the emergency stop button is pressed. Measures: restore the emergency stop button, replace the button, and replace the CPU. Analysis: when the emergency stop button is pressed (2) and the LCD Chinese character display is displayed, the feedback button (terminals 21 and 22) is disconnected +24 V, and the CPU receives the signal display 312. If there is a +24 V voltage and the feedback button is normal again, that is, the CPU board has failed, which is generally caused by the disconnection of the buffer connecting line from the optocoupler on the CPU board to the in-phase output. The connecting line is under the capacitor and is disconnected due to capacitor leakage. Replace the capacitor with a new one and connect the connecting line to restore the CPU board to normal use

(4) fault symptom 4: 779 is displayed on the screen, and the brake is overheated. Measures: eliminate overheating factors and check whether the thermistor and +12v voltage are normal. Analysis: +12v is connected to the CPU board through the thermistor. When it is overheated, the resistance is blocked, and the CPU cannot receive the +12v high-level signal, displaying 779, which plays a protective role

(5) fault phenomenon 5: let off motor cannot operate. Measures: adjust the tension and replace the frequency converter. Analysis: if the tension problem is displayed, the fault can generally be eliminated by adjusting the tension. If the display cannot increase or decrease the tension, it is generally the fault of the frequency converter. Replace the frequency converter

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