The switching power supply is the heart of the inverter and is responsible for the power supply of other parts, so its normal starting is the primary condition for dynamic maintenance of the inverter. Want to know more about industrial circuit boards, elevator circuit boards, inverters, please pay attention to "start the inverter repair from scratch."
Figure 1 Is the starting vibration good?
The key to switching power supply is whether it can start normally at the starting point. The starting point is the lowest PN voltage (230VDC) that enables the IC Board of the switching transistor MOSFET to operate normally.
Test method: remove the fuse in the upper left corner of the motherboard, and connect the analog load resistor board (this board can be made by yourself: add several resistors at the power output of the motherboard, such as adding a 2K/1W between 24V and COM). Resistor, +5V——Between GND, add a 1K/1W resistor and an LED in series for power indication.) The power-on method is shown in Figure 8.4.1.
On the switching power input P and the common negative terminal N, use a voltage regulator to add to about 230VDC to observe whether the power indicator on the analog load board is bright.
The good work of the switching power supply requires loading, but it cannot be directly added to the CPU board for testing. The purpose of adding the analog load is to prevent the CPU from being burnt out if the power supply is too high, or because the CPU board is faulty.
The design value of the starting point of the KVF+415GR switching power supply is 230VDC, which will be biased in actual operation, but will not exceed ±30VDC. If it exceeds this range, long-term work will damage the power supply and other components.