Rockwell Automation 140U Q, M Frame CB Installation and Operation for Thermal Magnetic Trip Units - Manual

40752-077(2) Effective 5/02
DO NOT ATTEMPT TO INSTALL OR PERFORM
MAINTENANCE ON EQUIPMENT WHILE ITS IS
ENERGIZED. DEATH, SEVERE PERSONAL INJURY,
OR SUBSTANTIAL PROPERTY DAMAGE CAN
RESULT FROM CONTACT WITH ENERGIZED
EQUIPMENT. ALWAYS VERIFY THAT NO VOLTAGE IS
PRESENT BEFORE PROCEEDING WITH THE TASK,
AND ALWAYS FOLLOW GENERALLY ACCEPTED
SAFETY PROCEDURES.
ALLEN-BRADLEY IS NOT LIABLE FOR THE
MISAPPLICATION 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 all general and local health and
safety laws, codes, and procedures.
The recommendations and information contained herein
are based on Allen-Bradley experience and judgement,
but should not be considered to be all-inclusive or cover-
ing every application or circumstance which may arise. If
any questions arise, contact Allen-Bradley for further
information or instructions.
1. INTRODUCTION
Fig. 1-1 Q-Frame and M-Frame Circuit
Breaker Thermal-Magnetic Trip Unit
General Information
Trip units for Q-frame and M-frame circuit
breakers (Fig. 1-1) are available in two types:
thermal-magnetic trip functions, described in this
instruction leaflet or electronic trip functions,
covered in Instruction Leaflet 40752-072. Trip
units are listed in accordance with Underwriters'
Laboratories, Inc. Standard UL489 and satisfy the
applicable requirements of the International Electro-
technical Commission Recommendations for molded
case circuit breakers.
The trip unit includes either a fixed or an adjustable ther-
mal element for inverse time delay on overload and an
adjustable magnetic element for protection against short
circuits. In open air at 40°C, the trip unit continuously car-
ries a current (l
n
) equal to the ampere rating marked on
the trip unit nameplate without exceeding a 50°C rise at
the terminals. The National Electrical Code (USA)
requirements state that enclosed overcurrent protective
devices may be loaded to a maximum of 80 percent of
the open air rating (I
n
).
The trip unit cover is factory sealed to prevent tampering
with the calibration. Tables 1-1 and 1-2 list catalog num-
bers and electrical data for trip units.
Thermal Trip: The thermal element trips the circuit
breaker within 2 hours for an overload of 135 percent and
trips in less time for higher overloads. For all currents in
excess of the magnetic setting, the tripping action is
instantaneous. In the overload trip region (up to 6 x I
n
),
the trip current times are the same for AC or DC.
WARNING
Q and M-Frame Circuit Breaker
Instruction Leaflet for Installation and Operation for
Thermal Magnetic Trip Units
Bul. 140U
Magnetic Trip: The magnetic trip on each pole may be
adjusted by turning the adjustment button with a screw-
driver (see Fig. 2-3). In the magnetic trip region (above 6
x In), the trip current levels can be up to approximately 40
percent higher for DC than for AC, depending on the rat-
ing.
Note: Trip units are calibrated at 40°C, 50/60 Hz and
DC as noted. Consult Allen-Bradley for derating at
other frequencies and ambient conditions.