Dosing pump circuit protection

[GregNv]

Hi all,

I have designed the next overcurrent, surge and RFI protection circuit for three dosing pumps.


The current and voltage of the pumps are 1A and 220V each and they are driven, switching the live ON/OFF with relays.
The MOV would have a Max. cont. voltage of 275V and the choke would be 20mH.
Do you think the design is right? Should I use a thermal fuse next to the MOV to protect it? Should I use and RFI filter instead of the choke?

Thank you in advance

Greg

 

[Harald Kapp]

Should I use a thermal fuse next to the MOV to protect it?

That would invalidate the function of the MOV as an open MOV will no longer protect the circuit.
If you need to resort to this kind of circuit, I suggest you use a specialized component: A MOV with integrated fuse.

Should I use and RFI filter instead of the choke?

Depensd on the residual interference from the current circuit, hard to measure without specialized equipment. Genereally a complete RFI Filter (including chokes and suitable capacitors) will suppress EMI better than the simple choke in this design.

 

[GregNv]

Thank @Harald Kapp for you advice. I will use the MOV with the integrated fuse and a RFI filter in the design.