Some customers reported that the 12v mini gas station power supply was easy to burn out. To find out the cause of the burnout, technical engineers finally discovered the problem after continuous testing. The following is the 12v mini gas station power supply test process and solution.
The 12v mini gas station underwent a long-term refueling test. At first, everything was normal during the refueling test, and the motor temperature was also normal. At first, I did not pay attention to the position of the terminals. Occasionally, I saw that the power incoming line seemed to be crooked. If I looked carefully, the terminals were a little burned, causing the power cord to move to the side.
2. Cause analysis
The melting of the terminals must be caused by excessive temperature. After recalculating the operating current of the DC motor.
The DC motor power is 550W, the voltage is DC12V, the current is about 550/12=45.8A, and the working current of the terminal is 45A.
Although it is a critical value, it will not burn out. After monitoring the operating current of the motor, it was found that when the oil gun discharges oil normally, the operating current of the motor is smaller than the rated value, about 30A.
However, when the oil gun does not discharge oil, the operating current of the motor pump will increase to about 60A.
If the motor load exceeds the rated value, the current will be much larger than the rated value, which will cause the motor to heat up. During the test, the oil gun is often turned off,
allowing the motor to run at full load, resulting in excessive current, exceeding the rated current of the terminal, causing the terminal to burn out.
1) The terminal was re-selected and a terminal with a rated current of 60A was purchased. After replacement, no further burnout of the terminal was found during the entire testing process.
2) The diameter of the power cord connected to the motor is 6mm2. The safe current carrying capacity of the 6mm2 copper wire found on the Internet is 48A. Although it is less than the maximum operating current of the motor, it is greater than the normal operating current. During the long-term test, the power cord became slightly warm, but it did not affect use, so the power cord was not replaced.
When selecting a device, you must consider not only the current under rated conditions, but also the current under abnormal conditions, and then select the appropriate device after comprehensive consideration.