IEEE C37.17-2012 pdf download IEEE Standard for Trip Systems for Low-Voltage (1000 V and below) AC and General Purpose (1500 V and below) DC Power Circuit Breakers
3.Definitions
For the purposes of this document, the following terms and definitions apply. The IEEE StandardsDictionary Online Bl] should be consulted for terms not defined in this clause.
An asterisk (*) indicates that at the time this standard was approved, there was no corresponding definitionin IEEE Std C37.100, while a dagger (f) indicates the definition differs from that in IEEE Std C37.100. Foradditional definitions see lEEE Std C37.13 and IEEE Std C37.14.
current sensor: A current transforming device, designed specifically for use as part of an electronic tripsystem, which provides an output signal or signals representative of the primary current. The output signaor signals of the current sensor ay be voltage and or current, dependent on the trip systerm design.”
direct-acting overcurrent trip device (electromechanical): A direct-acting release or tripping system thatis completely self-contained and integral to a circuit breaker and is activated by the electromagnetic forcesproduced by the current flowing through the circuit breaker.
direct-acting overcurrent trip system (electronic): A direct-acting release or tripping system that iscompletely self-contained and integral to a circuit breaker, having overcurrent protective functionsaccomplished by means of analog or digital processing of the current sensor output and operation of a tripactuator to open the circuit breaker, Direct-acting overcurrent trip svstes may optionally include groundfault trip functions that require an external current sensor or sensors. Maximum tripping current may beixed or adjustable and shall not exceed the continuous current rating of the circuit breaker frame.
direct-acting trip device: A generic term that may be either a “direct-acting overcurrent trip device”ordirect-acting overcurrent trip system.
direct-acting: A release or tripping system that requires no external or supplemental power or controlcircuits to cause it to function.
dual trip device: A term historically used to refer to an LI trip device.
ground fault trip function with memory: A ground fault trip element that responds to an intermittentault to ground by integrating the magnitude of the ground current over time. This function produces a tripcommand when the integrated magnitude of the ground current exceeds a threshold level unless the timeduration of the current magnitude below the pickup setting exceeds a time period specified by themanufacturer, A time constant may be included to accelerate or retard the decay of the integrated valueover time.*
ground fault trip function: A trip function that responds to the net (phasor sum) current flowing in thephase (and optionally neutral) conductors or the total current flowing in the normal neutral-to-groundconnection that exceeds a predetermined value for a specified time.
high range instantaneous: A descriptor used to indicate an instantaneous trip function setting range offrom 300% to 1200% of the of the trip device current rating.
NOTE–This term is historically attached to electromechanical trip devices, and not typically applied to electronic tripsystems.
LI and LIG trip devices: A trip device consisting of long-time and instantaneous tripping functions. Thepresence of ground fault protection is indicated by G.
low range instantaneous: A descriptor used to indicate an instantaneous trip function setting range of from50% to 400% of the of the trip device current rating.
NOTE– This term is historically attached to electromechanical trip devices on dc circuit breakers.
LS and LSG trip devices: A trip device consisting of long-time and short-time tripping functions. Thepresence of ground fault protection is indicated by G.
LSI and LSIG trip devices: A trip device consisting of long-time, short-time and instantaneous trippingfunctions. The presence of ground fault protection is indicated by G.
pickup setting: The setpoint, adjustable by the user, at which a function becomes active.
rating plug: A component of a circuit breaker or trip device that is interchangeable and replaceable by theuser and which sets the continuous current rating of an electronic trip device. The setting established by therating plug shall not exceed the continuous current rating of the circuit breaker frame.
selective trip device: A term historically used to refer to an LS trip device.t
trip actuator: A device which functions to open the circuit breaker mechanically, without requiringexternal power, when an electrical signal from the electronic direct-acting overcurrent trip device initiatesoperation. Also referred to as “flux shifter,” “mag latch or “flux release solenoid.”*
trip device current rating: The value of curent upon which the long-time-delay phase trip function isbased.*