|
MOV stands for
Metal Oxide Varistor which are traditionally used for the protection of
LV,MV and HV power circuits. MOV’s have exceptionally high surge
handling capability. An MOV just 20 mm in diameter can handle an 8,000A
8/20uS pulse.
MOV’s have a
lifetime. The 8kA rating for the 20mm device is its “one shot”
rating. In theory, a second 8kA impulse could destroy it. In practice
failures are rare. Laboratory tests show that these ratings are
extremely conservative and typical varistors can absorb many times
their impulse rating.
Properly designed,
a small number of high energy parallel connected MOV’s can share
current very successfully. Current sharing actually improves as the
applied current increases. A far greater lifetime and reliability can
thus be obtained. This is how the Novaris multimov is able to achieve
its remarkable lifetime performance.
|
