[Power Maintenance] A brief description of the maintenance process after the explosion of the constant voltage constant current power fuse


On November 17, 2018, the company received an after-sale constant voltage constant current power supply, model HYJ-360E5, rated specification 5V40A, power failure mainly manifested in work, the fuse exploded.

China Hardware Business Network

After receiving the power, first disassemble the power supply. After the housing is removed, you can clearly see the black around the fuse, as shown in the following figure. Except for the fuse, no other components inside the power supply were scorched or damaged.

China Hardware Business Network

The fuse explosion is generally caused by excessive power supply current, and is closely related to the rectifier bridge and the switch tube. Therefore, first check whether these two components are normal.

China Hardware Business Network

Adjust the multimeter to buzzer (switch to measuring diode voltage drop, the voltage drop is very small, indicating device damage, internal short circuit.)

China Hardware Business Network

Turn the power supply over and measure the pins of the rectifier bridge and the switch tube. First look at the switch tube (MOS tube).

China Hardware Business Network

At this time, the multimeter displays a value of 0.001V (the displayed value is the voltage drop of the MOS tube), and a display of 0.001V indicates that the switch tube is damaged and there is a short circuit phenomenon.

China Hardware Business Network

Let's check the rectifier bridge again, and put the test leads on the pins of the rectifier bridge.

China Hardware Business Network

At this time, the multimeter also displays 0.001V, indicating that the rectifier bridge is the same as the switch tube, and there is also a short circuit phenomenon.

China Hardware Business Network

Because the switching tube and rectifier of this constant voltage and constant current power supply are short-circuited, the maintenance master suspects that the fast recovery diode may malfunction. (Fast recovery diode damage will result in low output voltage, and the control circuit will increase the PWM duty cycle, which may cause damage to the switching tube (varies by power supply))

Measure the diode pin with the multimeter's test lead. At this time, the multimeter is also in the buzzer gear and switched to measuring voltage.

China Hardware Business Network

The multimeter shows 0.049V, and the diode is also very likely to be damaged.

China Hardware Business Network

In summary, the damage of this constant-voltage constant-current power supply is due to the excessive load during use, which leads to excessive output current of the power supply. In order to determine the damaged components again, remove the components from the power supply and measure it again. Make sure that the switch tube, rectifier bridge, and diode are damaged. After replacement, power on and the power supply can be used normally.

================================================== ================================================== ======
For more information, please visit the adjustable power supply **, contact phone WeChat with the same number, contact qq '[Power Repair] A brief description of the repair process after the explosion of the constant voltage constant current power fuse

Locomotive Industry Roll Forming Line

Roofing Machine,Locomotive Industry Roll Forming Line,Locomotive Industry Roll Forming Machine,Locomotive Industry Roll Making Line

Xinxiang Tianfeng Machinery Manufacture Co., Ltd. , https://www.frollforming.de