Brochure
Table Of Contents
- Introduction
- Motor Failure and Protection
- Trip Class Designation
- Withstand Ratings
- Thermal Overload Relay
- Melting Alloy
- Non-Compensated Bimetallic
- Automatic Reset
- Ambient Temperature Compensated Bimetallic
- Thermal Overload Relay Trip Characteristics
- Solid State Overload Relay
- Additional Standard Features
- Optional Features
- Additional Standard Features
- Optional Features
- General
- Nameplate Versus NEC Full-load Current
- Service Factor
- Motor Branch Circuit Design
- Overload Relays
- Hand Reset Melting Alloy
- Accessories
- Isolated Auxiliary Contacts for Motor Logic Overload Relays
- DIN Adapter
- Lug-Lug/Lug-Extender Kits
- Remote Reset Module
- 4 – 20 ma DC Communication Module
- Contact Units for Melting Alloy Type Overload Relays
- Melting Alloy Overload Relay Jumper Strap Kits
- Bimetallic Overload Relays
- Motor Logic™ – Solid State Overload Relay
© 1998 Square D All Rights Reserved
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Thermal Unit Selection
Tables 78 thru 83
T
a
bl
e 81
Motor Full-Load
Current (Amp)
Thermal Unit
Number
52.2-55.6
55.7-58.8
58.9-62.5
FB 50.5
FB 52.5
FB 55.5
62.6-66.0
66.1-70.1
70.2-78.6
FB 58
FB 60
FB 63.5
78.7-92.0
92.1-102
103-114
FB 69
FB 77
FB 84
115-123
124-133
FB 92
FB 105
Table 83
Motor Full-Load
Current (Amp)
Thermal Unit
Number
2.30-2.60
2.61-2.87
2.88-3.17
FB 3.33
FB 3.71
FB 4.1
3.18-3.37
3.38-3.76
3.77-4.29
FB 4.5
FB 4.75
FB 5.3
4.30-4.75
4.76-5.26
5.27-5.51
FB 6.1
FB 6.75
FB 7.45
5.52-5.78
5.79-6.13
6.14-6.41
FB 7.8
FB 8.21
FB 8.6
6.42-6.75
6.76-7.09
7.10-7.57
FB 9.0
FB 9.5
FB 10.0
7.58-7.90
7.91-8.81
8.82-9.47
FB 10.6
FB 11.2
FB 12.1
9.48-10.0
10.1-10.7
10.8-11.4
FB 13.1
FB 13.9
FB 14.8
11.5-12.1
12.2-13.1
13.2-13.7
FB 15.6
FB 16.4
FB 17.6
13.8-14.7
14.8-16.0
16.1-17.3
FB 18.4
FB 19.4
FB 21.1
17.4-18.2
18.3-19.4
19.5-20.7
FB 22.6
FB 23.6
FB 24.8
20.8-22.3
22.4-23.5
23.6-24.2
FB 26.7
FB 28.3
FB 29.6
24.3-26.0 FB 30.5
T
a
bl
e 80
Motor Full-Load
Current (Amp)
Thermal Unit
Number
20.5-21.7
21.8-23.1
23.2-24.8
FB 26.7
FB 28.3
FB 29.6
24.9-26.5
26.6-28.4
28.5-30.4
FB 30.5
FB 32.6
FB 34.1
30.5-32.8
32.9-34.9
35.0-37.3
FB 38.3
FB 40.2
FB 42
37.4-39.8
39.9-42.5
42.6-45.8
FB 44
FB 46
FB 48
45.9-48.2
48.3-50.6
50.7-53.1
FB 50.5
FB 52.5
FB 55.5
53.2-56.5
56.6-59.4
59.5-63.4
FB 58
FB 60
FB 63.5
63.5-71.0
71.1-78.8
78.9-86.0
FB 69
FB 77
FB 84
Table 82
Motor Full-Load
Current (Amp)
Thermal Unit
Number
2.36-2.63
2.64-2.96
2.97-3.23
FB 3.33
FB 3.71
FB 4.1
3.24-3.45
3.46-3.86
3.87-4.44
FB 4.5
FB 4.75
FB 5.3
4.45-4.95
4.96-5.47
5.48-5.75
FB 6.1
FB 6.75
FB 7.45
5.76-6.09
6.10-6.42
6.43-6.75
FB 7.8
FB 8.21
FB 8.6
6.76-7.16
7.17-7.43
7.44-7.99
FB 9.0
FB 9.5
FB 10
8.00-8.46
8.47-9.19
9.20-9.74
FB 10.6
FB 11.2
FB 12.1
9.75-10.3
10.4-10.8
10.9-11.6
FB 13.1
FB 13.9
FB 14.8
11.7-12.2
12.3-13.1
13.2-13.7
FB 15.6
FB 16.4
FB 17.6
13.8-14.3
14.4-15.5
15.6-16.7
FB 18.4
FB 19.4
FB 21.1
16.8-17.6
17.7-18.6
18.7-19.9
FB 22.6
FB 23.6
FB 24.8
20.0-21.1
21.2-25.0
FB 92
FB 105
T
a
bl
e 79
Motor Full-Load
Current (Amp)
Thermal Unit
Number
3.31-3.67
3.68-4.23
4.24-4.69
FB 4.75
FB 5.3
FB 6.1
4.70-5.21
5.22-5.49
5.50-5.74
FB 6.75
FB 7.45
FB 7.8
5.75-6.07
6.08-6.35
6.36-6.71
FB 8.21
FB 8.6
FB 9.0
6.72-7.03
7.04-7.53
7.54-7.91
FB 9.5
FB 10
FB 10.6
7.92-8.53
8.54-9.14
9.15-9.71
FB 11.2
FB 12.1
FB 13.1
9.72-10.2
10.3-10.8
10.9-11.5
FB 13.9
FB 14.8
FB 15.6
11.6-12.3
12.4-13.0
13.1-13.9
FB 16.4
FB 17.6
FB 18.4
14.0-15.1
15.2-16.1
16.2-16.9
FB 19.4
FB 21.1
FB 22.6
17.0-17.9
18.0-19.4
19.5-20.7
FB 23.6
FB 24.8
FB 26.7
20.8-21.7
21.8-22.3
22.4-23.9
FB 28.3
FB 29.6
FB 30.5
24.0-25.1
25.2-25.9
26.0-27.1
FB 32.6
FB 34.1
FB 35
27.2-28.6
28.7-30.1
30.2-31.7
FB 36.6
FB 38.3
FB 40.2
31.8-33.3
33.4-34.5
34.6-36.5
FB 42
FB 44
FB 46
36.6-38.5
38.6-39.9
40.0-45.0
FB 48
FB 50.5
FB 52.5
T
a
bl
e 78
Motor Full-Load
Current (Amp)
Thermal
Unit
Number
1 T. U.
2 T. U. or
3 T. U.
2.26-2.51
2.52-2.82
2.83-3.09
2.26-2.51
2.52-2.82
2.83-3.09
FB 3.33
FB 3.71
FB 4.1
3.10-3.30
3.31-3.69
3.70-4.27
3.10-3.30
3.31-3.69
3.70-4.27
FB 4.5
FB 4.75
FB 5.3
4.28-4.72
4.73-5.25
5.26-5.53
4.28-4.72
4.73-5.25
5.26-5.53
FB 6.1
FB 6.75
FB 7.45
5.54-5.81
5.82-6.14
6.15-6.44
5.54-5.81
5.82-6.14
6.15-6.44
FB 7.8
FB 8.21
FB 8.6
6.45-6.81
6.82-7.19
7.20-7.59
6.45-6.81
6.82-7.19
7.20-7.59
FB 9.0
FB 9.5
FB 10
7.60-7.99
8.00-8.17
8.18-8.74
7.60-7.99
8.00-8.17
8.18-8.74
FB 10.6
FB 11.2
FB 12.1
8.75-9.31
9.32-9.94
9.95-10.5
8.75-9.31
9.32-9.94
9.95-10.5
FB 13.1
FB 13.9
FB 14.8
10.6-11.1
11.2-11.9
12.0-12.4
10.6-11.1
11.2-12.0
....
FB 15.6
FB 16.4
FB 17.6
12.5-13.1
13.2-14.3
14.4-15.3
....
....
....
FB 18.4
FB 19.4
FB 21.1
15.4-15.9
16.0-18.0
....
....
FB 22.6
FB 23.6
Following Selections for Size 1
Only.
....
....
....
12.0-12.4
12.5-13.1
13.2-14.3
FB 17.6
FB 18.4
FB 19.4
14.4-15.3
15.4-15.9
16.0-16.9
14.4-15.3
15.4-15.9
16.0-16.9
FB 21.1
FB 22.6
FB 23.6
17.0-18.3
18.4-19.5
19.6-20.5
17.0-18.3
18.4-19.5
19.6-20.5
FB 24.8
FB 26.7
FB 28.3
20.6-21.1
21.2-22.6
22.7-23.7
20.6-21.1
21.2-22.6
22.7-23.7
FB 29.6
FB 30.5
FB 32.6
23.8-24.3
24.4-26.0
23.8-24.3
24.4-26.0
FB 35