One important factor that causes circuit board failures is the unstable working voltage supplied to the circuit board.
What situations can cause voltage instability? Personnel engaged in equipment maintenance can develop relevant measures based on the analyzed reasons, in order to avoid or reduce circuit board failures caused by voltage instability.
The factors of voltage instability generally include the following: unstable power supply voltage in the power grid. This situation is when the transmission line of the power grid is too long, causing significant losses during transmission, and the compensation capacitor capacity in the power grid decreases. If it is not replaced in a timely manner, the voltage may fluctuate from high to low. For this situation, it only needs to be replaced with a good compensation capacitor to solve it.
Large electrical appliances do not use specialized transformers and do not take corresponding measures to cause voltage instability.
If there are too many large and heavy load electrical appliances (such as large motors, lifting equipment, etc.) on the transmission line, and they are frequently started without installing voltage drop start protection, the high starting current at the beginning of the start will instantly lower the voltage of the power grid. After normal startup, the voltage will rise back to the original voltage value, resulting in high and low voltage.
For this situation, it is necessary to add a step-down starting device (usually by adding a soft starter or frequency converter) to the electrical appliance, so that it does not lower the grid voltage during startup, which can solve this problem.
The anti interference protection circuit in the input power circuit is not perfect, and interference pulses are mixed into the input power circuit, resulting in voltage instability.
This situation is usually caused by the designer’s lack of thorough consideration or effort to reduce costs during design, resulting in poor anti-interference circuits and some interference sources being input into the circuit board along with the input power supply , causing the voltage supplied to the circuit board to rise and fall, resulting in circuit board failure. In this case, as long as anti-interference circuit components are added to the input circuit, the situation of high and low voltage caused by interference can be avoided.