hello:
Regarding the circuit in the diagram, my understanding is that in PFC mode, pre-charging is performed through RF1-RF4 first, and then the DSP provides a control signal to close the relay. However, in the experiment, I did not plug in the DSP control card and directly connected the three-phase power supply. At this time, RF1-RF3 quickly burned out and smoked. What could be the reason for this? I checked the datasheet of RF and found that its power rating is limited to 2W. Is this too low for a 47-ohm resistor?
thanks
