I've learned so much from this awesome forum—my earlier designs that got reviewed here are performing great out in the field! Huge thanks especially to @jim-p —you've been a game-changer, and I'm truly grateful.
Could really use your eyes on my latest PCB design—details below! Please!
The output from the screw terminal VFD connects to a DELTA VFD-L 0.2kW 1 Phase. The three connections are AVI, M0 and GND on the VFD.
The output from the screw terminal Pump drives a 12V DC water pump.
The rest of the components are common with my previous designs. Hence, I am confident of their workings.
I review everything over and over again. The schematic you shared has two advantages:
1. Smaller-sized capacitor
2. Two op-amps for better regulation output
If it’s feasible, can you share the source of the schematic you provided? Just for reference, and to study further.
Second, I couldn’t find any issue with the relay module apart from the supply of 5V by mistake.
Third, I don’t see any issue with the pump controller. I did a small prototype here also, worked well. The pump consumes 250mA at 12VDC, and the MOSFET's max capacity is 50A. Are you directing me to use a relay module instead?
Three, it works.
It's my design. C1,R1,C2,R2 are two low pass filters used to "smooth out" the PWM. R3, R4 provide a gain of 2, so for 5V PWM you get 10V out. The second opamp is just a unity gain buffer to provide isolation.
RE Relay circuit:
Are you sure that Q2 is in saturation when on?
RE pump:
What about a diode?
Are you using PWM for the pump?
Theoretically, all tutorials I have read suggest that Beta Forced should be close to 10. Some suggest between 10 and 20. That's why I thought B(F) of 7 would be a safe bet.
