ABB Automation Inc.
Substation Automation and Protection Division
Coral Springs, FL 33065
Instruction Leaflet
All possible contingencies which may arise during installation, operation or maintenance, and all
details and variations of this equipment do not purport to be covered by these instructions. If further
information is desired by purchaser regarding this particular installation, operation or maintenance
of this equipment, the local ABB Power T&D Company Inc. representative should be contacted.
ABB
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CAUTION
Before putting relays into service, remove all
blocking which may have been inserted for the
purpose of securing the parts during ship-
ment, make sure that all moving parts operate
freely, inspect the contacts to see that they
are clean and close properly, and operate the
relay to check the settings and electrical con-
nections.
1.0 APPLICATION
These relays have been specially designed and
tested to establish their suitability for Class 1E appli-
cations in accordance with the ABB Power T&D
Company program for Class 1E Qualification Testing
as detailed in bulletin STR-1.
“Class 1E” is the safety classification of the electric
equipment and systems in nuclear power generating
stations that are essential to emergency shutdown of
the reactor, containment isolation, cooling of the
reactor, and heat removal from the containment and
reactor, or otherwise are essential in preventing sig-
nificant release of radioactive material to the environ-
ment.
The type CRN-1 relay is a single phase directionally
controlled timing relay used to protect ac generators
from motoring. When such a condition occurs and
persists for a predetermined time interval, the gener-
ator may be tripped or an alarm sounded. The
CRN-1 may also be used to sense lagging power
factor load flow in an abnormal direction. The direc-
tional unit has 30 degree maximum torque character-
istics and the timer unit is adjustable from
approximately 2 to 40 seconds.
2.0 CONSTRUCTION AND OPERATION
The relay consists of a directional unit, a timing unit,
and an indicating contactor switch unit.
These units have been specially designed to meet
the fragility requirements of a seismic environment.
In most cases, the construction is similar to the non-
seismic units except spring restraint is greater and
therefore more power is required to make them oper-
ate.
The timer unit is similar to Type CV relay described in
I.L. 41-201.4.
The CV unit contains a special shield covering the
spring, located above the disc, to prevent the spring
from contacting grounded elements during extreme
vibrations.
The ICS has a single operate rating and requires
special calibration procedures to make it less sensi-
tive to vibration.The internal schematic of the CRN-1
is shown in figure 1, page 7.
2.1
CV TIMER UNIT (T)
A spring shield covers the reset spring of the CV unit.
To remove the spring shield, requires that the damp-
Effective: July 1999
Supersedes I.L. 41-251.21B, dated July 1998
(
) Denotes Change Since Previous Issue
Type CRN-1
Reverse Power Relay
50 and 60 Hz
Class 1-E Applications
41-251.21C
R
