Industrial Automation
Catalog Section - U906
Circuit Breakers
NRA Series
Circuit Breakers
For up-to-date information, or to request a
full copy of this catalog, contact us at
www.idec.com
or
800-262-IDEC.
.
Due to continuous product improv ements,
specifications are subject to change
wihtout notice.
Circuit Breakers
Selection Guide
N-2
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Selection Guide: NRA Series
1. For dimensions, see page N-25.
2. NRAR is not CSA certified.
3. UL recognized, applicable standard: UL1077, “Supplementary Protectors.”
4. Not suitable for branch circuit protection.
Series Model NRAS NRAN NRAR
Page
N-4 N-4 N-4
Appearance
Actuator Style
Lever Lever
Rocker
(non-illuminated
and illuminated)
Number of Poles
1, 2, 3 1, 2, 3 1
Protection Method
Electromagnetic trip
Internal Circuits
Series current trip
Auxiliary Contact
Optional (250V AC, 5A; 50V DC, 1A)
Alarm Contact
Optional (250V AC, 5A; 50V DC, 1A)
Inertia Delay
Optional (for resistance to high in rushes)
Time Delay Curves
2 types for DC; 3 types for AC
Rated Voltage
250V AC, 50/60Hz, 65V DC
Rated Tripping Currents
0.30A, 0.50A, 0.75A
1A, 2A, 3A, 5A, 7.5A, 10A, 15A, 20A, 25A, 30A
Rated Interruption Capacity
1,000A, 250V AC, 50/60Hz, 65V DC
Approvals
UL, CSA UL
Selection Guide
CSA Certified
File No. LR47985
UL Recognized
File No. E68029
E74843
Pending
* NRA Series Only
Circuit Breakers
NRA Series
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NRA Series
Key features of the NRA series include:
• Available in 5 different styles
• Excellent overload and short circuit protection
• Small size and high-efficiency
• Life expectancy of over 10,000 operations
•
UL1077 recognized “Supplementary Protectors
”
CSA Certified
File No. LR47985
UL Recognized
File No. E68029
E74843
NRAS NRAN
NRAR
Rocker
NRAR
I
lluminated Rocker
(neon lamp)
1. NRAR is not CSA certified.
2. Not suitable for branch circuit protection.
Specifications
Protection Method
Electromagnetic tripping
Internal Circuit
Series current trip
Number of Poles
NRAS and NRAN: 1, 2, 3
NRAR: 1
Rated Voltage
250V AC, 50/60Hz, 65V DC
Rated Tripping Currents
0.30A, 0.50A, 0.75A
1A, 2A, 3A, 5A, 7.5A, 10A, 15A, 20A, 25A, 30A
Rated Interrupting Capacity
250V AC, 50/60Hz, 1,000A
65V DC, 1,000A
Auxiliary Contact
Alarm Contact
SPDT microswitch 250V AC, 5A (resistive load)
50V DC, 1A (resistive load)
Reference Temperature
25°C
Operating Temperature
–40 to +85°C (avoid freezing)
Insulation Resistance
100M
Ω
minute (measured with 500V megger)
Dielectric Strength
Between main circuit terminals: 2,000V AC, 1 minute
Between main circuit and auxiliary contact: 2,000V AC, 1 minute
Vibration Resistance
100N (approximately 10G) (10 to 100Hz)
Shock Resistance
1,000N (approximately 100G)
Life Expectancy
Minimum 10,000 cycles (at 6 operations per minute)
Termination
Main terminal: Quick-connect receptacle 0.250" (accepts M3.5 screw terminal adapter)
Auxiliary contact, alarm contact: Quick-connect receptacle 0.080"
Illumination Voltage
(
NRAR illuminated units)
Neon: 120, 240V AC, 50/60Hz
LED: 12, 24V DC
Circuit Breakers
NRA Series
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NRA series part numbers are composed of up to 8 part number codes. When ordering an NRA series part, select one code from each category.
Example: NRAR 1 1 11 -F - 30A -AA -3
Part Number Codes: NRA Series
1. For NRA series accessories, see page N-7.
2. For NRA series time delay curves, see page N-9.
3. For NRA series dimensions, see page N-25.
4. Not suitable for branch circuit protection.
5. UL recognized, applicable standard: UL1077, “Supplementary Protectors.”
6. NRAR is not CSA certified.
Description Part Number Code Remarks
➀
Model
Toggle (round cutout) NRAS
Toggle (rectangular cutout) NRAN
Rocker NRAR
➁
No. of Poles
1-pole 1 NRAR available in 1-pole only.
All multi-pole circuit breakers are simultaneous
throw/simultaneous break.
All levers are mechanically interlocked.
2-pole 2
3-pole 3
➂
Internal Circuit
Series current trip 1
➃
Auxiliary and
Alarm Contacts
Without 00
With auxiliary contact 11
With alarm contact 21
⑤
Inertia Delay
Without inertia delay Blank
With inertia delay F
➅
Rated Current
Rated current (current trip) 0.30A, 0.50A, 0.75A, 1A, 2A, 3A, 5A,
7.5A, 10A, 15A, 20A, 25A, 30A
All current ratings must be listed in amps (A).
Example conversions: 50mA = 0.05A, 300mA = 0.30A.
➆
Time Delay
Curve
DC curves AD, MD For time delay curves, see page N-9.
AC curves AA, BA,MA
⑧
Pilot Light*
With neon light 120V AC (50/60Hz) 1 * Applicable to illuminated NRAR only.
With neon light 240V AC (50/60Hz) 2
Part Numbering Guide
➀ Model ➁ Poles
11 3
1F30A AA
NRAR 1
➂ Internal
Circuit ➃ Auxiliary and
Alarm Contacts ⑤ Inertia
Delay ➅ Rated Current ➆ Time Delay ⑧ Pilot
Light *
Curve
Circuit Breakers
NRA Series
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Time Delay Curve Descriptions
Inertia Delay Descriptions
Circuit breakers equipped with inertia delay do not respond to high inrush currents such as
those produced by transformer, lamp, or motor loads, but perform the specified interruption
on the rated overcurrents.
Specify inertia delay by inserting an “F” in the part number as shown in Part Number Guide
on previous page.
Multi-Pole
Multi-pole types such as 2- or 3-pole should be assembled by IDEC.
Because of their characteristics, 1-pole breakers cannot be combined to provide multi-pole units.
Auxiliary and Alarm Contacts
Multi-pole units can incorporate auxiliary and alarm contacts.
Auxiliary and alarm contacts will not work with IDEC’s DIN rail adapters.
Time Delay Curve NRA Application
AD, AA Common curves used in molded-case circuit breakers.
BA
Response to overcurrent is quite fast. Suited for protection of semiconductor circuits with
very little overload tolerance. If overcurrents are expected to flow, fuses may be required
according to the circuit characteristics.
MD, MA Suited for motor loads that draw high inrush currents lasting a considerable length of time.
With Inertia Delay Designed not to trip on 20 times the rated current (peak value) for a duration of 8ms. Suited for
transformer and lamp loads that draw steep inrush currents.
Information About Circuit Breakers
Pulse Peak
Pulse (duration)
16,000
14,000
12,000
10,000
8,000
6,000
4,000
2,000
12345678910
Current
Width
Pulse Width (ms)
Percent of Rated Current
1. Percent of Rated Current =
2. Based on sinusoidal or parabolic pulse profile.
x 100%
Pulse Peak Current
Protector Rated Current
Notes
Circuit Breakers
NRA Series
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Part Numbers: NRA Series Accessories
Part Numbers: NRA Mounting Accessories
For dimensions of NRA series accessories and panel cut-out layouts, see drawings starting on page N-25.
Description Appearance Part No. Remarks
Color Caps
(NRAS only)
Red
NR5R
Colored caps fit onto NRAS circuit breakers for color coding circuits and
improving the appearance of the panel.
Blue
NR5S
Yellow
NR5Y
White
NR5H
Terminal Socket
MS-1C For connection with auxiliary or alarm contact terminals.
Screw Terminal Adapter
(1 pair)
NRT
For use on main terminals only.
Includes M3.5 clamp screw.
For dimensions see page N-25.
Description Appearance For Model No. of
Poles Part No. Remarks
Panel Mount
Flush Plate
NRAN
NRAR 1-pole NR31
Use of a flush plate makes
snap-in mount possible for
NRAN, and NRAR
circuit breakers (tightening
screws not necessary).
Multiple units can mount in
a single panel cut-out.
NRAN 2-pole NR32
NRAN 3-pole NR33
DIN Rail
Plug-in Base
NRAS
NRAN
1-pole NR21
1.Furnished with a hold-
down spring.
2.Applicable only for series
trip units up to 20 amps.
3.Not applicable for NRAR
lighted series.
4.Not for use with circuit
breakers incorporating
auxiliary or alarm contacts.
2-pole NR22
3-pole NR23
NRAR 1-pole NR211
Surface Mount
Plug-in Base
NRAS
NRAN
1-pole NUS1
2-pole NUS2
3-pole NUS3
NRAR 1-pole NUS11
Accessories
Ø 0.62"
(15.8mm)
Colored
Panel
Cap
1.89"
(48.5mm)
2.65"
(68mm)
2.46"
(63mm)
0.936"
(24mm)
Mounting 0.757"
(19.4mm)
1.50"
(38.5mm)
2.26"
(58mm)
DIN Rail
Hold-Down
1-Pole 2-Pole
3-Pole
Clip
Spring
Circuit Breakers NRA Series
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LINE
LOAD
Series Current Trip
NC
NO
LINE
C
LOAD
Series Current Trip
with Auxiliary Contacts
NO
NC
LINE
C
LOAD
Series Current Trip
with AlarmContacts
Series Current Trip
with Auxiliary Contacts
LOAD
C
NO
NC
LINE
Series Current Trip
with Alarm Contacts
LOAD
C
NC
NO
LINE
Pilot Lights (NRAR only)
Dashed lines represent
NRAR illuminated rocker
units. Lead wires for neon
pilot light/LED are color-
coded as shown above.
Lead Wire
Pilot Light A B
Neon
(120V AC) White White
Neon
(240V AC) Black Black
Lead
Lead
Wire A
Wire B
Lead
Lead
Wire A
Wire B
Internal Circuits and Terminal Arrangements: NRAS and NRAN Series
LINE
LOAD
(+)
(–)
Series Current Trip
Internal Circuits and Terminal Arrangements: NRAR Series
Circuit Breakers NRA Series
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Overcurrent — Time Delay Characteristics in Seconds (at 25°C)
1. All values above are in seconds.
2. Data in this table is equivalent to information presented in following time delay curves.
Percent of Rated Current
Curve 100% 125% 150% 200% 400% 600% 800% 1000%
DC
AD No trip 10 – 130 6 – 55 2.6 – 20 0.5 – 3.5 0.12 – 1.4 0.008 – 0.1 0.005 – 0.05
MD No trip 35 – 400 20 – 200 7 – 60 1.3 – 8 0.2 – 3 0.01 – 0.25 0.006 – 0.08
AC (50/60Hz)
AA No trip 10 – 120 6 – 45 2.2 – 15 0.3 – 2 0.05 – 0.55 0.007 – 0.13 0.005 – 0.04
BA No trip 0.75 – 10 0.45 – 3.5 0.22 – 1.3 0.045 – 0.22 0.012 – 0.12 0.005 – 0.06 0.004 – 0.03
MA No trip 60 – 900 30 – 260 9 – 70 1.5 – 8 0.18 – 2.5 0.009 – 0.25 0.006 – 0.08
Time Delay Curves (numerical equivalent)
DC Time Delay Curves
1,000
100
10
1
0.1
0.01
100
125
150
200 300 400 500 600 700 800 900 1,000
Time in Seconds
Percent of Rated Current
AD Delay Curve
at 77˚F (25˚C)
1,000
100
10
1
0.1
0.01
100
125
150
200 300 400 500 600 700 800 900 1,000
Time in Seconds
Percent of Rated Current
MD Delay Curve
at 77˚F (25˚C)
Circuit Breakers NRA Series
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1,000
100
10
1
0.1
0.01
100
125
150
200 300 400 500 600 700 800 900 1,000
Time in Seconds
Percent of Rated Current
AA Delay Curve
at 77˚F (25˚C)
1,000
100
10
1
0.1
0.01
100
125
150
200 300 400 500 600 700 800 900 1,000
Time in Seconds
Percent of Rated Current
BA Delay Curve
at 77˚F (25˚C)
AC (50/60Hz) Time Delay Curves
1,000
100
10
1
0.1
0.01
100
125
150
200 300 400 500 600 700 800 900 1,000
Time in Seconds
Percent of Rated Current
MA Delay Curve
at 77˚F (25˚C)
Circuit Breakers NRA Series
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Resistance and Impedance Characteristics
Coil Data for Series Current Trip at 25˚C
Tolerance ±25% (up to 20A), ±50% (25A and over).
Voltage Drop Due to Resistance or Impedance
The internal resistance or impedance of a circuit breaker tends to be larger for
a smaller rated current. Therefore, when circuit breakers with a small rated
current are used, voltage drop should be taken into consideration. Internal
resistance also varies with time delay curves, even at the same rated current.
This should also be considered during installation.
Time Delay Curve and Ambient Temperature
Since NRA series circuit breakers employ an electromagnetic tripping system,
the rated current (trip current) is not affected by the ambient temperature, but
the time delay varies with the oil viscosity in the tube. Lower oil viscosity at
higher temperatures results in shorter delay; whereas at lower temperatures,
the delay will be prolonged. The time delay curves, shown starting on page N-
9, are at 25°C. Time delay curves can be corrected.
Rated
Current DC Resistance AC Impedance
(50/60Hz)
Curves AD, MD Curves AA, BA,
MA
0.30A 9.67Ω9.82Ω
0.50A 3.24Ω3.36Ω
0.75A 1.45Ω1.49Ω
1A 0.90Ω0.92Ω
2A 0.21Ω0.21Ω
3A 0.09Ω0.092Ω
5A 0.036Ω0.036Ω
7.5A 0.017Ω0.018Ω
10A 0.012Ω0.012Ω
15A 0.0066Ω0.0068Ω
20A 0.0048Ω0.0048Ω
25A 0.0043Ω0.0043Ω
30A 0.0036Ω0.0041Ω
100
10
1
0.1
0.01
0.001 0.01 0.1 1 10 100
Rated Current (A)
Coil Resistance (Ω)
Coil Resistance at 25°C
Curves AD, MD
100
10
1
0.1
0.01
0.001 0.01 0.1 1 10 100
Rated Current (A)
Impedance (Ω)
Curves AA, BA, MA
200
100
80
60
40
–40 –20 025 50 70
Rated Current (A)
Ambient Temperature (°C)
400
90
Curves AD, AA, BA
(on 125% rated current)
Temperature Correction Curves
Circuit Breakers Instructions
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.
Description Circuit Example
Series Trip
This is the most common circuit breaker, providing excellent overload and short circuit
protection. It can also be used as an ON/OFF switch.
Series Trip with Auxiliary Contact
Since the auxiliary contact operation is interlocked with the ON/OFF of the main contactor,
circuit breaker operation can be monitored by a lamp or buzzer. This circuit breaker can
also be used to control auxiliary circuits up to 250V AC/5A (resistive load).
Series Trip with Alarm Contact
Since the alarm contact is electrically independent of the main contactor, but actuates
when the protective element operates. The alarm can be used with a lamp or buzzer to
monitor trip operations, and can also be used for controlling alarm circuits. The contact
rating is 250V AC/5A (resistive load).
Instructions: All Series
General
IDEC’s circuit breakers have been developed for the protection of electrical
circuits and small-sized electrical equipment and provide excellent protection
against overloads and short-circuits.
Additionally, IDEC’s circuit breakers are designed to suit specific needs. Each
series offers unique circuit protection characteristics and a choice of actuator
styles.
IDEC’s Circuit Breaker Features
• Various models are available with different internal circuits, tripping charac-
teristics, and rated currents
• 1- to 3- multi-pole
• Inertia delay
• Auxiliary contacts and alarm contacts
• The electromagnetic tripping system is not affected by ambient temperature
• Safe trip-free mechanism
• Vibration- and impact-resistant design
• When using accessories such as plug-in bases, flush plates, and colored
caps, a variety of mounting styles is possible — such as DIN rail mount-
ing, snap mounting into panel cut-outs, and color-coded arrangement on
the panel
Mounting Instructions: Installation Angle
Designed to be mounted on a vertical surface, the circuit breakers should be
mounted on a surface within 10° of the vertical plane. If the circuit breaker is
mounted on a horizontal surface or at any angle other than the specified
angle, its characteristics will be changed.
Multi-Pole Assemble
Multi-pole types such as 2- or 3-pole should be assembled by IDEC.
Because of their characteristics, 1-pole breakers cannot be com-
bined to produce multi-pole units.
Applications
The IDEC NRA circuit breaker series features superior overload and short-cir-
cuit protection. Many combinations of protection mechanisms and internal
circuit connections enable wide applications.
• Precision measuring instruments: electronic counters, projection
instruments, oscilloscopes, industrial instrumentation, and analytic
devices
• Electronic communication devices: facsimile machines, computers,
recorders
• Industrial machinery: printers, elevators, cranes
• Chemical and food industry machines: vacuum devices, wrappers,
centrifuges, agitators
• Machine tools: mill grinders, drills, presses
• Business machines: automatic vendors, medical equipment, beauty
salon equipment, entertainment games
• Other: office equipment, air-conditioners, conveyor belts, and many more
How the Breaker Operates
IDEC’s hydraulic magnetic circuit breakers operate like a solenoid coil. The
coil unit consists of an oil-filled tube with a metal core at one end and a pole
piece and armature at the opposite end with a spring in between.
When a current load passes through the coil winding, it creates a magnetic
field. As long as the current load is either at or below the nominal rating of
the breaker, the metal core will remain stationary.
If the current load increases beyond the nominal rating, the strength of the
magnetic field causes the core to move toward the pole-end of the tube. The
oil viscosity regulates the core’s movement through the tube, thereby regulat-
ing the time delay. As the percentage of current load increases, the required
trip time of the breaker decreases and vice versa.
When the current reaches the overload rating, the metal core will meet the
pole piece at the opposite end of the tube. At this point, the armature is
attracted to the same pole piece, tripping the breaker.
In case of sudden short circuit, the magnetic field created will instantly trip
the breaker.
Internal Circuits Overview
Load
Load A
Load B
Load A
Load B
Circuit Breakers Dimensions
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Dimensions
Dimensions: NRA Series
0.745"
(19.1mm) 0.745"
(19.1mm) 0.745"
(19.1mm)
1.65" (42.2mm)
2.03" (52mm)
1-pole: 0.745" (19.1mm)
2-pole: 1.49" (38.2mm)
3-pole: 2.23" (57.3mm)
1.20"
(30.8mm)
60°
0.250" Tab Terminal
0.110" Tab Terminal
1.56" (40mm)
1.56" (40mm)
1.93" (49.5mm)
2.11" (54mm)
0.683"
(17.5mm)
NRAS
0.745"
(19.1mm) 0.745"
(19.1mm) 0.745"
(19.1mm)
2.03" (52mm)
1.65"(42.2mm)
1.23"(31.5mm)
1-pole: 0.745" (19.1mm)
2-pole: 1.49" (38.2mm)
3-pole: 2.23" (57.3mm)
1.20"
(30.8mm)
0.250" Tab Terminal
0.110" Tab Terminal
1.56" (40mm)
0.644"
(16.5mm)
1.60" (41mm)
1.97" (50.5mm)
2.11" (54mm)
60°
NRAN
0.745"
(19.1mm)
LED
ON
OFF
1.23" (31.5mm)
1.65" (42.2mm)
2.03" (52mm)
0.250" Tab Terminal
0.110" Tab Terminal
0.78" (20mm)
1.56" (40mm)
0.417"
(10.7mm)
2.18" (56mm)
2.55" (65.5mm)
2.69" (69mm)
NRAR
1.20"
(30.8mm)
Dimensions: NRBM Series
0.745"
(19.1mm) 0.745"
(19.1mm) 0.745"
(19.1mm)
1.37" (35mm)
2.04" (52.3mm)
2.46" (63mm)
1-pole: 0.745" (19.1mm)
2-pole: 1.49" (38.2mm)
3-pole: 2.23" (57.3mm)
1.35"
(34.7mm)
60°
M5 Stud 0.110" Tab Terminal
1.92” (49.2mm)
0.8"
(20.5mm)
1.85" (47.5mm) 0.624"
(16mm)
2.48" (63.5mm)
NRBM
Circuit Breakers Dimensions
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NRA Series
Maximum Mounting Distance
Model A B Schematics in Inches (mm)
NRAS 3.02" (77.5mm) 3.57" (91.5mm)
NRAN 3.02" (77.5mm) 3.57" (91.5mm)
NRAR 3.38" (86.7mm) 3.93" (100.7mm)
Installation Angle: Circuit breakers are designed to operate on a vertical surface. The mount-
ing angle should not exceed a vertical plane by more than 10°.
Panel Cut-Outs
0.745"
(19.1mm)
1.66"
(42.2mm)
0.630"
(16mm)
Ø0.158" (4mm)
Mounting Holes Ø0.156" (4mm)
Mounting Holes
0.745"
(19.1mm)
1.66"
(42.2mm)
1.26"
(32mm)
1-Pole
2-Pole
3-Pole
0.745" (19.1mm)
1.49" (38.2mm)
2.23" (57.3mm)
NRAS NRAR, NRAN
0.20" (5.1mm)
1.05"
(26.7mm)
2.09"
0.764"
1.51"
2.25"(57.8mm)
(53.5mm)
(38.7mm)
(19.6mm)
NR31, NR32, NR33 — Panel Mount Flush Plate
Mounting to Panel Surface Mounting to DIN Rail
