1
40752-195 (1)
Effective
2
/201
1
Installation Instructions for Bul. 140
U
N-Frame Circuit Breakers and Molded
Case Switches
DO NOT ATTEMPT TO INSTALL OR PERFORM MAIN-
TENANCE ON EQUIPMENT WHILE IT IS ENERGIZED.
DEATH, SEVERE PERSONAL INJURY, OR SUBSTAN-
TIAL PROPERTY DAMAGE CAN RESULT FROM
CONTACT WITH ENERGIZED EQUIPMENT. ALWAYS
VERIFY THAT NO VOLTAGE IS PRESENT BEFORE
PROCEEDING WITH THE TASK, AND ALWAYS FOL-
LOW GENERALLY ACCEPTED SAFETY PROCE-
DURES.
ALLEN-BRADLEY
IS NOT LIABLE FOR THE MIS
APPLI-
CATION
OR MISINSTALLATION OF ITS PRODUCTS.
The user is cautioned to observe all recommendations,
warnings and cautions relating to the safety of personnel
and equipment as well as general and local health and
safety laws, codes and procedures.
The recommendations and information contained herein
are based on Rockwell experience and judgement, but
should not be considered to be all-inclusive or covering
every application or circumstance which may arise. If any
questions arise, contact Rockwell for further information
or instructions.
1. INTRODUCTION
The N-Frame Circuit Breaker (Figure 1-1) are 690VAC
maximum rated devices, 600V for UL applications, and
have integral trip units. Available current ratings are up
to 1600 Amp, 1200 for UL applications. I N-Frame Circuit
Breakers and molded case switches are listed in ac-
cordance with Underwriters Laboratories, Inc. Standard
UL-489 and satisfy the requirements of the International
Electrotechnical Commission Recommendations No. IEC
60947-2.
Th
e
Trip Units are AC only devices that
employ
microprocessor based technology that provides
true
RMS current sensing means for proper correlation
with thermal characteristics of conductors and equipment.
The primary function of the Trip Unit is circuit protection.
This is achieved by analyzing the secondary current
signal received from the circuit breaker current sensors and
initiating trip signals to the circuit breaker shunt trip when
pre-set current levels and time delay setting are exceeded.
Low level ground fault protection with an adjustable time
delay is supplied when appropriate trip types are selected.
In open air at 40º C, a N-Frame Circuit Breaker with a
Trip Unit will carry continuously up to 1200 amperes without
exceeding a 50º C rise at the terminals. The calibration
of the trip unit is insensitive to ambient temperatures over
a range of -20º to +55º C. However, the trip unit contains
thermal temperature protective circuitry that initiates a trip
operation for self-protection if the internal ambient tem-
perature at the printed circuit board (PCB) reaches approxi-
mately 90º C. For ambient conditions above 40º C, derat-
ing of the circuit breaker should be considered to avoid
exceeding a safe terminal temperature operation range.
Consult
Allen-Bradley
for recommendations.
Figure 1-1 N-Frame Circuit Breaker
Bul. 140
U
