Jim Bryan (retired)
EASA Technical Support Specialist

Voltage surges come in many forms, all of which can be devastating to an electric motor. Transient conditions, rapid bus transfer, ungrounded systems, reclosure, improperly located power factor correction (PFC) capacitors, accidental connection of a new dual-voltage motor for the wrong voltage, and lightning are all sources of damaging surges. Here, we would like to discuss two of these sources: rapid bus transfer and reclosure.  Rapid bus transfer occurs when the voltage source is changed from the primary to a secondary source or back. This might occur when an automatic back-up source is brought on line during a power outage. Reclosure is similar but may include the automatic reclosing of an overcurrent device or “chatter” in a switch or circuit breaker.

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