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 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 Capacitors reduce the slope of the surge (rate of voltage rise) by momentarily absorbing initial energy, then releasing it; providing a "Dampening Effect".
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.
The selection of the surge protection package is based on the motor voltage. We supply 460V, 2300V, and 4160V surge packages as standard.