Electric Motor Control Basics - Book - Page 82
NEMA vs IEC Motor Controls
NEMA Rating
The NEMA ratings of a starter depends largely on the maximum horsepower ratings
given in the National Electrical Manufacturers Association ISCS2 standard. The
selection of the NEMA starters is done on the basis of their NEMA size, which varies
from Size 00 to Size 9.
NEMA Contactor and Starter Sizes
NEMA Size
Continuous AMP Rating
HP at 230 VAC
HP at 460 VAC
00
9
1
2
0
18
3
5
1
27
5
10
2
45
15
25
3
90
30
50
4
135
50
100
5
270
100
200
6
540
200
400
7
810
300
600
8
1215
450
900
9
2250
800
1600
The NEMA starter, at its stated rating, can be used for a wide range of applications,
ranging from simple on and off applications to plugging and jogging applications,
which are more demanding. It is necessary to know the voltage and horsepower of
the motor when selecting the proper NEMA motor starter. In the case where there is
a considerable amount of plugging and jogging involved, then derating a NEMA-rated
device will be required.
Industrial Control
Basics:
Part 1, Contactors
Industrial Control
Basics: Part 2,
Overload Relays
Industrial Control
Basics: Part 3,
Starters
The Benefits of Type E/F
Motor Protection
Circuit Breakers
Basic Pump Control:
Three Phase DOL Starter
Control of an Electric Pump
Applying Motor Control
in a Wastewater
Application
NEMA vs IEC Motor
Controls
Understanding
IP Ratings
82
