In electronic circuits, many failures are caused by switching power failures, and most of the common failures of the switching power supply are caused by damage to some vulnerable parts. For example, the switch tube in the switching UPS is often damaged, but the switch transformer has a very low probability of damage, almost negligible. So I summed up some of the components which are easily damaged in switching power supply, and what will happen after the damage.
1.Protective tube
Most of the burning protective tube is caused by the large current of the post level circuit, that is, the circuit behind is short circuited, such as the switch tube, the current limiting resistance, the bridge pile burning the short circuit, the chip damage, the large filter capacitor damage and so on, all will cause the burning of the Protective tube, the failure phenomenon is no response to the electricity. If you change the protective tube, do not rush the electricity test, we must find fault or take some measures before the electrified.
2.Filter capacitor damage
Filter capacitor leakage or capacity reduction, will cause a crash or boot no response, filter capacitor damage generally visible from the capacitor drum can be seen.
3.Output filter capacitor
The fault phenomenon is similar to the filter capacitor damage.
4.Switch tube
In first point, the switch is damaged after the damage generally will be burned, the current resistance will follow the damage, and some time even PWM chips are also burned, but this phenomenon is not much. Since the protective tube has been burned, the fault must be energized and unresponsive.
5.Voltage regulator diode
In the case where the reverse voltage of the diode is greater than its nominal voltage, the regulator will reverse the breakdown, but this kind of breakdown can be recovered, that is, after the voltage is reduced, the regulator will break out of the breakdown state. If it is short circuited, then the regulator tube has been damaged, and the current exceeds the voltage regulator tube to withstand the current, resulting in thermal breakdown and is not recoverable.
6.Optical coupler and TL431
The damage of these two components usually causes unstable output voltage or no voltage output.
7.Starting resistance
The starting resistor is connected between the 300V power supply and the base of the switch tube. The damage of the starting resistor will cause 300V, but no voltage output, and the whole machine has no response.
8.Current limiting resistance
The resistance damage to the overcurrent protection circuit is the same as that of the starting resistor. 300V has no output voltage.
9.PWM control chip
PWM damage will cause 300V, but no output voltage can be repeated to burn off the switch tube and insurance, detection can be used to judge the ground resistance to judge its good or bad, normal to ground resistance to the ground, other pins are hundreds of ohms.
SHW48200 48VDC Outdoor Power Supply MPPT Off-Grid Telecom Station Solar Hybrid System
■Adopt advanced MCU microprocessor control technology.
■Advanced MPPT Technology,High converting efficiency higher than 97% for minimizing energy loss.
■Reversed current protection at night, over voltage and reverse polarity protection.
■Capable of selecting different charging mode for various types of batteries.
■Protection degree:IP55
■Industy-leading power density compact size and high reliability;
■Doorframe designed with waterproof structure, posted on the seal and equipped with waterproof lock on the door double insulation design;
■Cabine adopt quality galvanized sheet or aluminum coated steel sheet as material, surface coating anti-UV power;
■Suitable for outdoor installation.
