The protection function of the power supply is mainly overvoltage and overcurrent protection.
The connection between overvoltage and overcurrent protection is:
When any kind of power supply has defects, it may cause the output voltage or output current to lose control. In order to prevent the user's load from being damaged, our DC power supply is generally equipped with overvoltage and overcurrent protection. For some loads, such as resistive loads, when the power supply has shortcomings, the voltage on the load may rise sharply, and the increase in current may not exceed the overcurrent protection value. In this case, overvoltage protection should be used. For example, when operating at 50V, the voltage protection value can be adjusted to 55v. Assuming that the power supply has shortcomings, the power supply will automatically block the voltage output when the voltage rises to 55v. When some loads are capacitive loads, because the high-capacity electrolytic capacitors are connected in parallel, when the power supply has shortcomings, the current may rise significantly, but the increase in voltage is not obvious. At this time, the overcurrent protection components inside the power supply will be initiated first, and the power supply will automatically block the output.
The overvoltage protection value has a potentiometer on the panel, which can be set manually. The overcurrent protection value cannot be set manually. It has been fixed in the machine, which is generally 1.2 ~ 1.5 times of the rated current. It should be noted that the overvoltage protection will be initiated immediately, and the overcurrent protection will have a delay of about one second. This is because when the power supply operates normally, if the load of the power supply is suddenly short circuited, the instantaneous current output by the power supply is several times or dozens of times of the rated current, which can be considered as a current shock, far exceeding the value of overcurrent protection, but overcurrent protection is not expected to work at this time. After the short circuit is expected to be eliminated, the voltage will automatically return to normal. Therefore, when planning overcurrent protection, it is necessary to avoid the current impact in case of sudden short circuit, and only consider making the duration of output overcurrent reach a certain value to initiate overcurrent protection.
Overvoltage and overcurrent protection is aimed at the internal shortcomings of the machine. Therefore, since it occurs, the power supply should not be restored automatically. Assuming that it must be reproduced, it is necessary to shut down and restart. The functions of short-circuit protection, current alarm and short-circuit alarm are faced with users. Assuming that the current has decreased and the short-circuit has been cleaned, the relative alarm sound will be automatically eliminated and the voltage will automatically return to normal.
