MOVs and surge suppressors

Many surge suppressors on the market (I'm only talking about the MOV
type here, not the fancy induction style) have little indicator lights
to tell you if the thing is still providing protection. How do they
do this? I thought the only way to test a MOV was to send a surge
through it, and then you will only know what condition it was in
before you sent in the surge. What is the circuit diagram for one of
these indicator LEDs, and is this a way to test any MOV or MOV device?

Thanks.

.

Relevant Pages

  • Re: MOVs and surge suppressors
    ... I thought the only way to test a MOV was to send a surge ... and is this a way to test any MOV or MOV device? ... Plug-in suppressors have their current limited by the significant impedance of the branch circuit. ... protector was so grossly undersized as to be permanently destroyed. ...
    (sci.electronics.basics)
  • Re: MOVs and surge suppressors
    ... I thought the only way to test a MOV was to send a surge ... and is this a way to test any MOV or MOV device? ... They do not protect by absorbing surge energy, but in the process of protecting they absorb enengy. ... protector was so grossly undersized as to be permanently destroyed. ...
    (sci.electronics.basics)
  • Re: Does a MOV shunt current or equalize voltage?
    ... A MOV across a relay coil shunts nothing to ground and protects entirely by voltage limitation, absorbing the energy stored in the relay coil. ... For a service panel suppressor, with a MOV from hot to neutral/ground/earthing-electrode-, say a 10,000A surge arrives on a hot service wire. ...
    (sci.electronics.design)
  • Re: Intermatic Whole House Surge Protector ?
    ... While MOVs are good with very short duration surges, dropping a primary wire onto secondaries will rapidly destroy a MOV as you describe. ... The specs from trader4 include “200k AIC Surge Rated Fuses” which indicate that suppressor can be used on in a panel with an available fault current of 200,000A. ... The suppressor may also trip a circuit breaker, ... The 40,000A rating goes with a very high Joule rating, which means the suppressor can take many hits. ...
    (alt.home.repair)
  • Re: House Power Failures and Mac
    ... If plug-in suppressors only last 3 years you are buying junk or are in an extremely high lightning area. ... One looks at a MOV at the end of a 10-50 meter branch circuit. ... The surge is 2,000-10,000A. ... This is where much of the surge energy is dissipated if there is no service panel suppressor. ...
    (comp.sys.mac.apps)