I have made the following circuit (copied from a very similar picture on internet):
At one side of AC/DC I put a normal fuse.
The MOV is a 14D391K 14K391 390V varistor diameter 14mm AC 250V DC 320V (similar to this datasheet.
However, as soon as I put 220 AC on the circuit, the fuse blew. I would expect that it would blow when it gets a power spike of over 390 V (AC).
I don't know if the varistor still works, but I removed it and the circuit works as it should be.
What did I do wrong?
I see that the voltage rating is 390 VDC, and the clamping rating is 650 V
- Does this mean that this varistor is not meant to be for AC ?
- How can the clamping rating be higher than the voltage rating?
- In case this varistor is to be used for AC, why does my fuse blows up when using this varistor?