GE Industrial Solutions Record Plus FG600 with SMR1 or SMR2 Trip Unit - Manual (Page 6)

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D – Circuit Breaker Operation
The breaker contact status is indicated by the handle position.
The positions are marked on both sides of the handle
escutcheon, clearly showing the status of the breaker contacts.
ON and/or I indicate the breaker is ON and OFF and/or O
indicate the breaker is OFF. The breaker tripped position is
indicated by the following symbol:
To close the breaker from the OFF position, move the handle to
the ON position. To close the breaker from the trip position, first
move the handle fully to the OFF (reset) position and then to the
ON position, as illustrated in Figure 5. A Push-To-Trip button is
provided for convenience in testing the mechanical trip
operation of the breaker, as shown in Figure 5. The Push-To-
Trip operation should be tested annually.
1. Trip Unit System Description
The SMR1 and SMR2 Electronic Trip Units (ETU) are designed for
use in Record+ Molded Case Circuit Breakers (MCCB). The ETU
is an electronic assembly, which interfaces with the circuit
breaker. It monitors the breaker phase currents and trips the
breaker in the event of an over current condition. ETU can be
powered from 3 sources: Auxiliary Power; Self-Power (i.e.,
current flowing through the breaker) or battery power. The Trip
Unit also connects with the circuit breaker flux shifter actuator
to provide the electro mechanical tripping function. A user
interface is provided on the front panel to allow adjustment of
the Trip Unit’s parameters.
The SMR1 is an electronic trip unit offering a set of
sophisticated protective functions. Designed for use with the
FG600 current limiting molded case circuit breakers, the device
has a fixed set of 2 protective functions allowing a selective
and fully adjustable protection against Overloads (Long Time)
and short circuits (Instantaneous). The SMR1 uses rating plugs
that gives the user the flexibility to make a last minute choice in
the required current rating, protected poles or protection band.
The SMR2 is an electronic trip unit offering a set of
sophisticated protective functions that can be extended at will
by the addition of separately available modules. Designed for
use with the FG600 current limiting molded case circuit
breakers, the device has a fixed set of 3 protective functions
allowing a selective and fully adjustable protection against
Overloads (Long Time) and short circuits (Short Time and
Instantaneous). Both the Long Time and Short Time protection
can be set to different delay bands or bands (Long Time Delay
and Short Time Delay) while the Short Time device can be
switched on or off to energy protection mode (I2t). The SMR2
uses rating plugs that gives the user the flexibility to make a
last minute choice in the required current rating, protected
poles or protection band. The SMR2 ETU can communicate with
any Modbus master (typically a PC) using Modbus protocol, if
used with External contact (FAMECM) Module.
SMR1 & SMR2 trip units have a built-in temperature sensor that
trips the breaker at temperatures above 85°C. It thus prevents the
breaker and electrical components in its immediate vicinity from
overheating.
SMR1 & SMR2 trip unit comes with a transparent, tamper-free
(sealable) cover, this to prevent unauthorized manipulation of
the breaker settings.
2. Overload protection LT ( long time)
The Long Time or overload protection is adjustable from 0.4 to
1X the rating plug in 16 steps. The user can also define
one of the 8 time bands (LTD) each designed to match specific
loads, motor or cable characteristics. Out of these 8 time band
settings, 5 have time bands for line applications and 3 are
dedicated to motor protection (for time band classes see EN
60947-4.1). When set to motor protection mode, a phase loss
protection is initiated that will trip the breaker when the
difference in current between one phase line and the average
of all three phases drops below 20%. This easy-to-adjust trip
unit is equipped with a LT load indicator device that operates
by means of two LED indicators located on the trip unit front
face. If the load reaches a 60% of the set Ir value, a green LED
will start to blink (3 flashes a second). When the load reaches
75% of Ir it will stop blinking and remain on. The second orange
LED will start to blink at 95% of the Ir value. It will remain on
when the load reaches 105% of Ir and a trip is imminent.
The SMR2 is also equipped with a so called thermal memory
device. This memory tracks overheating even after the device
has tripped and prevents the breaker from being switched
whilst its environment is still at a too high temperature.
3. Short-circuit Protection ST (short time, available
only in SMR2)
Offering a selective protection against low value short-circuits
the Short Time protection is settable from 2 to 10X the adjusted
LT protection (Ir) depending on the sensor rating. The device
can be set to five time setting bands (STD), this allowing
selectivity between different breaker sizes. The STD device can
be set to an 'energy curve mode'. This mode changes the fixed
delay and reaction time value of the device, when the set
current level is reached, into a reaction time that depends on
the energy flowing in the circuit.
4. Short-circuit Protection I (instantaneous)
Offering a protection against short-circuits the Instantaneous
protection is settable from 2 to 11X the chosen sensor rating.
The device has no time delay band so that the breaker
immediately trips when the set threshold is reached. Each
5. Ground Fault protection
The Ground Fault function computes the vector sum of the three
phase currents. If the vector sum exceeds the user set threshold
value for the set time delay, one of the following actions takes
place:
1.) GF version: The ETU issues trip command
2.) GFA version: The ETU sets alarm signal. (Circuit breaker
contact remains closed).
Ground Fault pickup settings range between 0.2 and 1X of sensor
rating.
When the breaker is equipped with a Communication and Control
Output Module option (with Target Communication Accessory) the
trip indication is also passed on through the communication
output as trip history.