Surge Protection
Description:
Surge protection equipment
is provided on induction motors to protect the motor against line surges. Line
surges may be caused by lightning strikes, capacitor switching, arcing strikes,
intermittent grounds, and power distribution failures.
A surge protection package consists of a dust and moisture proof enclosure with lightning arrestors and/or surge capacitors.
Lightning Arrestor:
Lightning arrestors limit the crest value of an impulse voltage. When the
voltage reaches a pre-determined value it provides a discharge path to ground.
It provides a "Spillover Effect".
Surge
Capacitor:
Surge Capacitors reduce the slope of
the surge (rate of voltage rise) by momentarily absorbing initial energy, then
releasing it; providing a "Dampening Effect".
Installation:
The surge
capacitor should be located between the motor and the lightning arrestors and as
close to the motor as possible for maximum effectiveness (Limiting capacitor
lead length to 3 feet is recommended). Fusing of the arrestors or capacitors is
not recommended because of the difficulty in determining if or when the fuse has
blown.
Selection:
The selection of the surge
protection package is based on the motor voltage. USEM supplies 460V, 2300V, and
4160V surge packages as standard.
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