ENGINEERING MANUAL OF AUTOMATIC CONTROL
GENERAL ENGINEERING DATA
487
Table 26. Conductor Sizes and Overcurrent Protection for Motors.
VOLTAGE CONVERSION
Table 27. Voltage Conversion Multipliers.
Desired Voltage
Existing Voltage EMS Effective Average Peak Peak-to-Peak
EMS Effective — 0.900 1.414 2.828
Average 1.110 — 1.570 3.141
Peak 0.707 0.637 — 2.000
Peak-to-Peak 0.354 0.318 0.500 —
Full Minimum Size of
Running
Protection
of Motors.
Maximum Allowable Rating or Setting (in Amperes) of Branch-Circuit,
Short-Circuit, and Ground-Fault Protective Devices
Load
Copper Wire, AWG
Maximum Note 1 ß Note 3 Note 4
Current
Rating of
Motor
Amperes
60C
TW,
UF
75C
RHW,
THW,
THWN
90C
RHH,
THHN
Setting of
Adjustable
Protective
Devices
Fuses
Inverse
Time
Circuit
Breaker Fuses
Inverse
Time
Circuit
Breaker Fuses
Inverse
Time
Circuit
Breaker Fuses
Inverse
Time
Circuit
Breaker
1
2
3
4
5
14
14
14
14
14
14
14
14
14
14
14
14
14
14
14
1.25
2.50
3.75
5.0
6.25
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
6
7
8
9
10
14
14
14
14
14
14
14
14
14
14
14
14
14
14
14
7.50
8.75
10.00
11.25
12.50
20
25
25
30
30
15
20
20
25
25
15
20
20
25
25
15
15
20
20
20
15
15
20
20
20
15
15
20
20
20
15
15
15
15
15
15
15
15
15
15
11
12
13
14
15
14
14
12
12
12
14
14
12
12
12
14
14
12
12
12
13.75
15.00
16.25
17.50
18.75
35
40
40
45
45
30
30
35
35
40
30
30
35
35
40
25
25
30
30
30
25
25
30
30
30
25
25
30
30
30
20
20
20
25
25
20
20
20
25
25
16
17
18
19
20
12
10
10
10
10
12
10
10
10
10
12
10
10
10
10
20.00
21.25
22.50
23.75
25.00
50
60
60
60
60
40
45
45
50
50
40
45
45
50
50
35
35
40
40
40
35
35
40
40
40
35
35
40
40
40
25
30
30
30
30
25
30
30
30
30
22
24
26
28
32
10
10
8
8
8
10
10
8
8
8
10
10
8
8
8
27.50
30.00
32.50
35.00
40.00
70
80
80
90
100
60
60
70
70
80
60
60
70
70
80
45
50
60
60
70
45
50
60
60
70
45
50
60
60
70
35
40
40
45
50
35
40
40
45
50
34
44
45
56
57
6
6
4
4
3
8
6
6
4
4
8
8
6
6
6
42.50
55.00
56.25
70.00
71.25
110
150
150
175
175
90
110
125
150
150
90
110
125
150
150
70
90
90
125
125
70
90
90
125
125
70
90
90
125
125
60
70
70
90
90
60
70
70
90
90
68
69
76
77
80
3
2
2
1
1
4
3
3
3
3
4
4
4
3
3
85.00
86.25
95.00
96.25
100.00
225
225
250
250
250
175
175
200
200
200
175
175
200
200
200
150
150
175
175
175
150
150
175
175
175
150
150
175
175
175
110
110
125
125
125
110
110
125
125
125
NOTES: 1. Single-phase all types with No Code letters.
All single-phase and polyphase squirrel-cage and synchronous motors with full voltage, resistor, or reactor starting,
no code letters or code letters F to V.
2. Squirrel-cage and synchronous motors:
With full voltage, resistor, or reactor starting, code letters b to e.
With autotransformer starting, not more than 30a with no code letters or more than 30a with code letters F to v.
High reactance squirrel-cage, not more than 30A, no code letters.
3. Squirrel-cage and synchronous motors with autotransformer starting more than 30A, no code letters. High
reactance squirrel-cage more than 30A, code letters B to E.
4. Squirrel-cage and synchronous motors with full voltage, resistor, or reactor starting or autotransformer starting with
more than 30A, code letter A. wound rotor, no code letter.
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