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Welcome to GTV! Today we are going to take a closer look at surge suppressors for ABB’s
across the line contactors. The operation of inductive circuits causes overvoltages,
in particular on opening of the contactor coil. The electromagnetic energy stored by
the coil during contactor closing is restored on opening in the form of surges, the slope
and amplitude of which may rise to several kilovolts. A number of drawbacks are observed
ranging from interference on the electronic devices to breakdown of insulators and even
destruction of certain sensitive components. To guard against the harmful effects of these
overvoltages, ABB has developed a range of surge suppressors designed to reduce the overvoltage
factor and to limit or even completely eliminate the high pre-damping voltage frequencies.
Each case is different, but the technical data tolerances and the generous sizing of
parts have enabled ABB to reduce the number of variants. A few solutions to this problem
include transil diodes, varistors and RC blocks. Surge Suppressors with a transil diode are
for DC unit. They have good energy absorption and an unpolarized system. Varistors are available
in DC and AC. They have high energy absorption, good dampening and are also an unpolarized
system. RC blocks have a very fast clipping, attenuation of steep fronts and high frequencies,
and no operating delays. RC blocks are available for AC units only. To find out more about
ABB’s across the line contactors and their accessories, please take a look at our other
videos on GTV. Surge Suppressor for ABB’s across the line contactors, along with thousands
of other products and services are available at galco.com.