alt.engineering.electrical

phil-news-nospam@ wrote:
> On Fri, 29 Feb 2008 02:23:56 -0500 Michael A. Terrell <@> wrote:
> | phil-news-nospam@ wrote:
> |>
> |> On Thu, 28 Feb 2008 01:45:12 -0600 bud-- <@> wrote:
> |>
> |> | Martzloff has also written "In fact, the major cause of TVSS [surge
> |> | suppressor] failures is a temporary overvoltage, rather than an
> |> | unusually large surge."
> |>
> |> And these would not damage the TV?
> |
> |
> | No. Why do you think it would? if the surge suppresser clips at a
> | safe voltage to protect from spikes, it won't go any higher with a
> | overvoltage condition, but the MOV or other protection device quickly
> | overheats as it tries to maintain the proper voltage. If the line
> | voltage is high enough, it will trip the Breaker, or blow the fuse for
> | that AC circuit. The protective device can only dissipate a small
> | amount of heat before it self destructs.
>
> This was a discussion about a suggestion tha the MOV condunction voltage
> should be higher than now used (330V for 120V systems). He wants to
> raise that voltage to avoid certain situations causing TVSS failure so
> the protection against spikes (above 800V) is maintained longer. My
> position is that the swells as high as 565V RMS could in fact cause
> damage to the TV. Under his proposal, these would be be suppressed.
> I think that is a bad idea because these voltage swells really can do
> damage.
.
Surge suppressors are intended to protect against surges. Raising the
clamp voltage is to lower unnecessary suppressor exposure to surges that
do not damage connected equipment.

Surge suppressors are not intended to protect against longer duration
swells or even longer duration overvoltage. Martzloff's comment above is
that the major cause of failure is overvoltage, which suppressors are
not intended to protect against.

If you keep the clamp voltage low, you are likely not increasing
protection from swells because a swell may well kill the MOV anyway. To
protect against overvoltage get a suppressor that disconnects on
overvoltage.

--
bud--