|
NEMA Size Starters for
Single-Phase Motors
Size of
Controller |
Continuous
Current
Rating
(Amperes) |
Horsepower |
| at
115V |
at
230V |
00
0
1
1P
2
3 |
9
18
27
36
45
90 |
1/3
1
2
3
3
7½ |
1
2
3
5
7½
15 |
Reference: NEMA ICS2-1993, Table
2-4-2.
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Derating Factors for Conductors
in a Conduit
Number of
Current
Carrying
Conductors |
Percent of Values in
Tables Adjusted
for Temperature
If Necessary |
4-6
7-9
10-20
21-30
31-40
41 & Above |
80
70
50
45
40
35 |
Reprinted with permission from NFPA 70-1996, National
Electrical Code,® copyright © 1996, National Fire Protection
Association, Quincy, Massachusetts 02269.
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Temperature Classification of
Insulation Systems
| Insulation Systems* |
Temperature Classification
|
Class A
Class E**
Class B
Class F
Class H
Class N |
Class 105
Class 120
Class 130
Class 155
Class 180
Class 200 |
105ºC
120ºC
130ºC
155ºC
180ºC
200ºC |
221ºF
248ºF
266ºF
311ºF
356ºF
392ºF |
*IEEE Std. 117.
**Used in European equipment.
Insulation systems are arranged in order of their insulation level and
classified by a letter symbol or by a numerical value.
The numerical value relates to the temperature classification of the
insulation system.
The temperature classification indicates the maximum (hot-spot)
temperature at which the insulation system can be operated for normal
expected service life.
In general, all materials used in a given insulation system should be rated
for temperatures equal to, or exceeding, the temperature classification of the
system.
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Resistance Temperature Detectors (RTDs)
| Metal |
Characteristic |
TRC (W/W/ºC)* |
| Copper |
10.0W @ 25ºC |
.00427 |
| Platinum |
100W @ 0ºC |
.00385 |
| Nickel |
120W @ 0ºC |
.00672 |
*TCR is the Temperature Coefficient of Resistance.
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Thermocouple Junction Types
| Junction Type |
Thermocouple Materials |
| E |
Chromel-Constantan |
| J |
Iron-Constantan |
| K |
Chromel-Alumel |
| T |
Copper-Constantan |
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