Order of magnitude of voltage of a conducting MOV

Thread Starter

alphacat

Joined Jun 6, 2009
186
When a MOV starts conducting, what is the order of magnitude of its voltage?

Perhaps you could please attach a graph of the Conducting Voltage Vs. Current of a MOV?

Thank you very much.
 

Thread Starter

alphacat

Joined Jun 6, 2009
186
Hey,

I looked at many datasheets but they never show there a graph of the conducting voltage or any indication on it.
 

Thread Starter

alphacat

Joined Jun 6, 2009
186
Hello,

Did you see the PDF of littlefuse on the page I gave you?

Greetings,
Bertus
Thank you for the attached pdf file.

Yes, I saw it and also other datasheets of Littlefuse TMOVs.

But i see no indication there on the MOV's voltage when its ON.
 

Thread Starter

alphacat

Joined Jun 6, 2009
186
Oh, now i see why i though i didnt see it.

I expected to have a very low "ON" voltage.
Should the MOV's voltage be very low when its ON, since it shunts the Live/Neutral line to Earth?

I thought that V_MOV(ON) would be very close to 0V.
 

bertus

Joined Apr 5, 2008
20,863
Hello,

As you see a MOV is clamping and not shorting.
If you want somethings that shorts, than you can make a crowbar with a thyristor/triac.
(also in the links of the educypedia page).

Greetings,
Bertus
 

Thread Starter

alphacat

Joined Jun 6, 2009
186
Oh i see, thank you :)

The voltage of a MOV with 400V clamping voltage will remain around 400V when its ON? (meaning, when its shunting current to Earth).
 

bertus

Joined Apr 5, 2008
20,863
Hello,

A MOV is acting like a sort of zener diode in two directions.
The clamping voltage is dependend on the amount of over voltage.
You can see in the graphs the voltage is a little bit higher when the clamping current is higher.

Greetings,
Bertus
 
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