Cutler Hammer, Div of Eaton Corp NEMA Contactors, NEMA Starters Application Information
February 2007
NEMA Contactors & Starters
Freedom
Relays — Thermal Overload
33-113
Contents
Description Page
Thermal Overload Relays
Product Description . . . . . . 33-113
Features . . . . . . . . . . . . . . . 33-113
Operation . . . . . . . . . . . . . . 33-113
Technical Information . . . . 33-113
Technical Data . . . . . . . . . . 33-114
Factory Modifications . . . . 33-115
Accessories. . . . . . . . . . . . . 33-115
Replacement Parts . . . . . . . 33-115
Dimensions. . . . . . . . . . . . . 33-116
Product Selection. . . . . . . . 33-117
Heater Pack Selection . . . . 33-117
32A Overload
Cat. No. C306DN3B
Product Description
C306 Overload Relays are designed for
use with CE or CN non-reversing and
reversing contactors. Four sizes are
available for overload protection up
to 144A.
Features
■ Selectable Manual or Automatic
Reset operation.
■ Interchangeable Heater Packs
adjustable ±24% to match motor
FLA and calibrated for use with 1.0
and 1.15 service factor motors.
Heater packs for 32A overload relay
will mount in 75A overload relay —
useful in derating applications such
as jogging.
■ Class 10 or 20 heater packs.
■ Load lugs built into relay base.
■ Bimetallic, ambient compensated
operated. Trip free mechanism.
■ Electrically isolated NO-NC contacts
(pull RESET button to test).
(Electrical Ratings see Table 33-160
on Page 33-114).
■ Overload trip indication.
■ Shrouded or fingerproof terminals
to reduce possibility of electrical
shock.
■ Meets UL 508 single-phasing
requirements.
■ UL listed, CSA certified, NEMA
compliance and CE mark.
Operation
C306 Overload Relay Setting
1.0
Service
Factor
A
Example of 12.0 FLA setting for
heater pack number H2011B showing
position for 1.0 or 1.15
service factor motors.
Figure 33-43. FLA Dial Adjustment
For motors having a 1.15 service factor, rotate the FLA adjustment dial to
correspond to the motor’s FLA rating.
Estimate the dial position when the
motor FLA falls between two letter
values as shown in the example.
For motors having a 1.0 service factor,
rotate the FLA dial one-half position
counterclockwise (CCW).
Example of setting for
Figure 33-44. Manual/Automatic Reset
The overload relay is factory set at M
for manual reset operation. For automatic reset operation, turn the reset
adjustment dial to the A position as
shown in the illustration.
Automatic reset is not intended for
two-wire control devices.
1.15
Service
Factor
BC
A
M
manual reset.
D
Test for Trip Indication
To test overload relay for trip indication when in manual reset, pull out the
blue reset button. An orange flag will
appear indicating that the device has
tripped. Push reset button in to reset.
Warning — To provide continued protection against fire or shock hazard,
the complete overload relay must be
replaced if burnout of the heater
element occurs.
Technical Information
General
“Overload relays are provided to protect motors, motor control apparatus
and motor-branch circuit conductors
against excessive heating due to
motor overloads and failure to start.
This definition does not include:
1) motor circuits over 600V, 2) short
circuits, 3) ground faults and 4) fire
pump control.” (NEC Art. 430-31)
Time Current Characteristics
The time-current characteristics of an
overload relay is an expression of performance which defines its operating
time at various multiples of its current
setting. Tests are run at Underwriters
Laboratories (UL) in accordance with
NEMA Standards and the NEC. UL
requires:
■ When tested at 100 percent of its
current rating, the overload relay
shall trip ultimately.
■ When tested at 200 percent of its
current rating, the overload relay
shall trip in not more than 8
minutes.
■ When tested at 600 percent of the
current rating, the overload relay
shall trip in not more than 10 or 20
seconds, depending on the Class
of the relay.
“Current Rating” is defined as the
minimum current at which the relay
will trip. Per NEC, an overload must
ultimately trip at 125% of FLA current
(heater) setting for a 1.15 service factor
motor and 115% FLA for a 1.0 service
factor motor.
“Current Setting” is defined as the FLA
(Full Load Amperes) of the motor and
thus the overload heater pack setting.
Example: 600% of current rating is
defined as 750% (600 x 1.25) of FLA
current (heater) setting for a 1.15 service factor motor. A 10A heater setting
must trip in 20 seconds or less at 75A
motor current for a Class 20 relay.
33
CA08102001E For more information visit: www.eaton.com
33-114
NEMA Contactors & Starters
Freedom
February 2007
Relays — Thermal Overload
33
10,000
5000
4000
3000
2000
1000
500
Trip Time
(Seconds)
400
300
200
100
50
40
30
20
10
5
4
3
2
1
0
246810
Multiples of Current Setting
Class 10 Overload Relay 25°C Open Rating
From
Cold Start
From
Hot Start
Figure 33-45. Class 10 and Class 20 Trip Curves
Technical Data
Table 33-156. Wire (75°C) Sizes — AWG or kcmil — NEMA Sizes 00 – 2,
IEC A – K — Open
IEC
Size
Power Terminals — Line
A, B, C
D, E, F
G, H, J, K
Power Terminals — Load — Cu Only (Stranded or Solid)
Catalog
Number
C306DN3B 32A 14 – 6 AWG
C306GN3B 75A 14 – 2 AWG
Control Terminals — Cu Only
12 – 16 AWG Stranded, 12 – 14 AWG Solid
Two compartment box lug.
Table 33-157. Wire (75°C) Sizes — AWG or kcmil — NEMA Sizes 3 – 8,
IEC L – N — Open
IEC Size NEMA Size Wire Size
Power Terminals — Line and Load
L
M
N
— 4 Open — 3/0 – 8 Cu
—5
Control Terminals — Cu Only
12 – 16 AWG Stranded, 12 – 14 AWG Solid
NEMA
Cu Only
Size
00
0
1
2
12 – 16 Stranded, 12 – 14 Solid
8 – 16 Stranded, 10 – 14 Solid
8 – 14 Stranded or Solid
3 – 14 (Upper) and/or 6 – 14
Terminal Wire Size
3
—
—
1/0 – 14 Cu/Al
1/0 – 8 Cu/Al
3/0 – 8 Cu/Al
Enclosed — 250 kcmil — 6 Cu/Al
750 kcmil — 2 or
6 – 7
8
(2) 250 kcmil — 3/0 Cu/Al
(2) 750 kcmil — 3/0 Cu/Al
(2) 750 kcmil — 1/0 Cu/Al
(Lower) Stranded or Solid
10,000
5000
4000
3000
2000
1000
500
Trip Time
(Seconds)
400
300
200
100
50
40
30
20
10
5
4
3
2
1
0
246810
Multiples of Current Setting
Class 20 Overload Relay 25°C Open Rating
From
Cold Start
From
Hot Start
Table 33-158. Power Terminal Torque Line and Load Terminals
Terminal Catalog Number Torque in lb-in
32A C306DT3B 20
75A C306GT3B 35 (14 – 10 AWG)
40 (8 AWG)
45 (6 – 4 AWG)
50 (3 – 2 AWG)
105A C306KN3
(Socket Head
Screw)
144A C306NN3
(Socket Head
Screw)
C306NN3
(Slotted Head
Screw)
120 (3/16)
200 (1/4)
250 (5/16)
120 (3/16)
200 (1/4)
250 (5/16)
35 (14 – 10 AWG)
40 (8 AWG)
45 (6 – 4 AWG)
50 (3 – 1/0 AWG)
Table 33-159. Plugging and Jogging Service Horsepower Ratings
NEMA Size 200V 230V 460V 575V
00
0
1
2
3
4
5
6
Maximum horsepower where operation is interrupted more than 5
—
125
15
25
60
1-1/2
3
7-1/2
150
10
20
30
75
1/2
1-1/2
3
150
300
1/2
2
5
15
30
60
1/2
2
5
15
30
60
150
300
times per minute or more than 10 times in a 10 minute period. NEMA
standard ICS 2-1993 table 2-4-3.
Table 33-160. Overload Relay UL/CSA Contact Ratings Control Circuit
AC Volts 120V 240V 480V 600V
NC Contact B600
Make and Break Amps 30 15 7.5 6
Break Amps 3 1.5 .75 .6
Continuous Amps 5 5 5 5
NO Contact C600
Make and Break Amps 15 7.5 3.375 3
Break Amps 1.5 .75 .375 .3
Continuous Amps 2.5 2.5 2.5 2.5
DC ratings cover Freedom Series coils only.
For more information visit: www.eaton.com CA08102001E
Loading...