Pickup is the setting of current, voltage, frequency or impedance at which a relay element starts timing toward a trip, and also the act of crossing that threshold. An overcurrent element set at 400 A pickup ignores 380 A and starts its curve at 400 A. The matching dropout or reset level is where the element returns to rest, and the gap between the two keeps the element from chattering when the measured value hovers near the setting.
Earth fault element picked up three times overnight without tripping, something is leaking right at the edge of the pickup.
Also heard as
- pick-up
- operate value
Related terms
IDMT
Inverse definite minimum time: an overcurrent curve that trips faster as current rises, down to a set minimum.
Chatter
Rapid repeated opening and closing of relay or contactor contacts, usually from marginal voltage or vibration.
Protection relay
Device that watches currents and voltages and orders a circuit breaker to trip when it detects a fault.