TERMINAL MARKINGS AND CONNECTIONS
PART WINDING START
NEMA NOMENCLATURE—6 LEADS
1
1
7
3
2
9
7
3
8
2
Delta
OPER.
MODE
START
RUN
9
8
Wye
1
9
L1
1
1,7
L2 L3 OPEN
2
3
7,8,9
T1
T2
T3
2,8 3,9 —
MOTOR LEADS
1
2
3
7
T7
3
7
T8
8
2T9
8 Delta 9
Double
(Extended Delta)
NEMA NOMENCLATURE—9 LEADS
WYE CONNECTED (LOW VOLTAGE ONLY)
MOTOR LEADS
T1
1
T2
2
T3
3
T7
7
T8
8
T9 Together
9 4&5&6
NEMA AND IEC NOMENCLATURE—12 LEADS
SINGLE VOLTAGE OR LOW VOLTAGE OF
DUAL-VOLTAGE MOTORS
12
NEMA
1
4
9
T1
NEMA
IEC
10
85
T2
U1
W5
W2
7
6
3
11
W6
IEC
U2
U5
2
W1
V6
V5 V2
T3
T7
T8
U6
V1
T9
1,6
2,4
3,5
7,12
8,10
9,11
U1,W2 V1,U2 W1,V2 U5,W6 V5,U6 W5,V6
1
TERMINAL MARKINGS AND CONNECTIONS
THREE-PHASE MOTORS–SINGLE SPEED
NEMA NOMENCLATURE—6 LEADS
SINGLE VOLTAGE
EXTERNAL WYE CONNECTION
L1
L2
L3
JOIN
1
2
3
4&5&6
1
4
6
3
6
SINGLE VOLTAGE
EXTERNAL DELTA CONNECTION
L1
L2
L3
1,6
2,4
3,5
5
2
1
3
4
5
2
SINGLE AND DUAL VOLTAGE
WYE-DELTA CONNECTIONS
6
1
4
3
5
6
1
4
3
2
5
2
SINGLE VOLTAGE
OPERATING
MODE
START
RUN
CONNECTION
L1
L2
L3
JOIN
WYE
DELTA
1
1,6
2
2,4
3
3,5
4&5&6
—
DUAL VOLTAGE*
VOLTAGE
CONNECTION L1
L2
L3
JOIN
HIGH
WYE
1
2
3
4&5&6
LOW
DELTA
1,6
2,4
3,5
—
*Voltage ratio: 1.732 to 1.
2
TERMINAL MARKINGS AND CONNECTIONS
THREE-PHASE MOTORS–SINGLE SPEED
NEMA NOMENCLATURE—9 LEADS
1
4
7
6
3
DUAL VOLTAGE
WYE-CONNECTED
9
85
2
VOLTAGE
L1
L2
L3
JOIN
HIGH
LOW
1
1,7
2
2,8
3
3,9
4&7,5&8,6&9
4&5&6
1
4
9
6
3
7
8
5
2
DUAL VOLTAGE
DELTA-CONNECTED
VOLTAGE
L1
L2
L3
JOIN
HIGH
LOW
1
1,6,7
2
2,4,8
3
3,5,9
4&7,5&8,6&9
—
3
TERMINAL MARKINGS AND CONNECTIONS
THREE-PHASE MOTORS–SINGLE SPEED
NEMA NOMENCLATURE–12 LEADS
1
4
7
DUAL VOLTAGE
EXTERNAL WYE CONNECTION
6
L2
2
L3
3
LOW
1,7
2,8
3,9
1
9
JOIN
4&7,5&8,6&9,
10&11&12
4&5&6,
10&11&12
12
4
7
6
1
4
9
6
7
3
85
2
5
2
L1
1
10
12 11
8
3
VOLTAGE
HIGH
3
9
10
12
11
11
8 5
10
2
DUAL VOLTAGE
WYE-CONNECTED START
DELTA-CONNECTED RUN
VOLTAGE
CONN. L1
L2
L3
HIGH
WYE
2
3
LOW
4
1
JOIN
4&7,5&8,6&9,
10&11&12
DELTA 1,12 2,10 3,11 4&7,5&8,6&9
WYE
1,7
2,8
3,9
4&5&6,
10&11&12
DELTA 1,6,7, 2,4,8, 3,5,9, —
12
10
11
TERMINAL MARKINGS AND CONNECTIONS
THREE-PHASE MOTORS–SINGLE SPEED
IEC NOMENCLATURE–6 AND 12 LEADS
SINGLE AND DUAL
VOLTAGE WYE-DELTA
CONNECTIONS
W2
U1
W2
U2
V2
W1
SINGLE VOLTAGE
CONN.
L1
L2
START
WYE
U1
RUN
DELTA
U1,W2
U2
W1
V1
OPER.
MODE
U1
V2
V1
L3
JOIN
V1
W1
U2&V2&W2
V1,U2
W1,V2
—
DUAL VOLTAGE*
VOLT.
CONN.
L1
L2
L3
JOIN
HIGH
WYE
U1
V1
W1
U2&V2&W2
LOW
DELTA
U1,W2
V1,U2
W1,V2
—
*Voltage ratio: 1.732 to 1.
U1
W6
U2
U5
W6
W1
W5
W2
U6
V6
U1
U2
U5
W5
W2
W1
V5
V2
V1
V6
V5 V2
U6
V1
DUAL VOLTAGE WYE-CONNECTED START
DELTA-CONNECTED RUN
VOLT.
CONN. L1
L2
L3
JOIN
HIGH
WYE
V1
W1
U2&U5,V2&V5,
W2&W5,U6&V6&W6
DELTA U1,W6
V1,U6
W1,V6
U2&U5,V2&V5,
W2&W5
WYE
V1,V5
W1,W5 U2&V2&W2,
U6&V6&W6
LOW
U1
U1,U5
DELTA U1,U5,
W2,W6
V1,V5, W1,W5, —
U2,U6 V2,V6
5
TERMINAL MARKINGS AND CONNECTIONS
THREE-PHASE MOTORS–TWO SPEED,
SINGLE WINDING
NEMA NOMENCLATURE–6 LEADS
4
3
CONSTANT TORQUE CONNECTION
Low-speed horsepower is half
of high-speed horsepower.*
SPEED
HIGH
LOW
L1
6
1
L2
4
2
L3
5
3
2
5
1&2&3 JOIN
4-5-6 OPEN
1
6
TYPICAL
CONNECTION
2 WYE
1 DELTA
4
VARIABLE TORQUE CONNECTION
Low-speed horsepower is
one-fourth of high-speed
horsepower.*
1
3
2
5
6
TYPICAL
CONNECTION
SPEED
L1
L2
L3
HIGH
6
4
5
1&2&3 JOIN
2 WYE
LOW
1
2
3
4-5-6 OPEN
1 WYE
4
3
CONSTANT HORSEPOWER CONNECTION
Horsepower is the same
at both speeds.
SPEED
HIGH
LOW
L1
6
1
L2
4
2
5
L3
5
3
1-2-3 OPEN
4&5&6 JOIN
1
2
6
TYPICAL
CONNECTION
1 DELTA
2 WYE
* CAUTION: On European motors horsepower variance with speed
may not be the same as shown above.
6
TERMINAL MARKINGS AND CONNECTIONS
THREE-PHASE MOTORS–TWO SPEED,
SINGLE WINDING
2U
IEC NOMENCLATURE–6 LEADS
1V
CONSTANT TORQUE CONNECTION
1U
2V
SPEED
HIGH
LOW
L1
2W
1U
L2
2U
1V
L3
2V 1U&1V&1W JOIN
1W 2U-2V-2W OPEN
VARIABLE TORQUE CONNECTION
2V
L1
2W
1U
L2
2U
1V
2W
TYPICAL
CONN.
2 WYE
1 DELTA
2U
1V
SPEED
HIGH
LOW
1W
1W
1U
2W
TYPICAL
L3
CONN.
2V 1U&1V&1W JOIN 2 WYE
1W 2U-2V-2W OPEN 1 WYE
7
TERMINAL MARKINGS AND CONNECTIONS
SINGLE-PHASE MOTORS–CAPACITOR-START
NEMA NOMENCLATURE
THERMAL
PROTECTOR
SINGLE VOLTAGE
MAIN (RUN) WINDING
P1
P2
1
4
8
AUXILIARY (START)
WINDING
5
CAP SWITCH
ROTATION
L1
L2
CCW
CW
1,8
1,5
4,5
4,8
DUAL VOLTAGE
(MAIN WINDING ONLY)
Auxiliary winding is always
at low voltage rating;
capacitor should be
rated accordingly.
THERMAL
PROTECTOR
P1
P2
1
MAIN (RUN) WINDING
2
3
4
8
AUXILIARY (START)
WINDING
5
CAP SWITCH
VOLTAGE
HIGH
LOW
8
ROTATION
CCW
CW
CCW
CW
L1
1
1
1,3,8
1,3,5
L2
4,5
4,8
2,4,5
2,4,8
JOIN
2&3&8
2&3&5
—
—
TERMINAL MARKINGS AND CONNECTIONS
SINGLE-PHASE MOTORS–CAPACITOR-START
NEMA NOMENCLATURE
DUAL VOLTAGE
(MAIN AND AUXILIARY WINDING)
Capacitors in auxiliary
windings are rated for
lower voltage.
THERMAL
PROTECTOR
P1
P2
1
MAIN (RUN) WINDING
CAP
CAP
AUXILIARY (START) WINDING
2
3
4
8
7
6
5
VOLTAGE
ROTATION
L1
L2
JOIN
HIGH
CCW
1,8
4,5
2&3,6&7
CW
1,5
4,8
2&3,6&7
CCW
1,3,6,8
2,4,5,7
—
CW
1,3,5,7
2,4,6,8
—
LOW
The switch in the auxiliary winding circuit has been omitted from
this diagram. The connections to the switch must be made so
that both auxiliary windings become de-energized when the
switch is open.
ROTATION:
CCW – Counter-clockwise
CW – Clockwise
The direction of shaft rotation can be determined by facing the
end of the motor opposite the drive.
TERMINAL MARKINGS IDENTIFIED BY COLOR
1-Blue
5-Black
P1-No color assigned
2-White
6-No color assigned
P2-Brown
3-Orange
7-No color assigned
4-Yellow
8-Red
NEMA MG 1-1998 (Rev. 3), 2.41. Note: May not apply for some
definite-purpose motors.
9
TERMINAL MARKINGS AND CONNECTIONS
FOR DC MOTORS (NEMA NOMENCLATURE)
SHUNT MOTOR
SHUNT FIELD
INTERPOLES
+
F1
A1
ARMATURE
-
A2
LINE
F2
LINE
COMPOUND MOTOR
SHUNT FIELD
INTERPOLES
F1
+
A1
ARMATURE
A2
SERIES
FIELD
S1
S2
LINE
-
F2
LINE
SERIES MOTOR
INTERPOLES
+
A1
LINE
ARMATURE
SERIES
FIELD
A2
S1
S2
-
LINE
All connections are for counterclockwise rotation facing the end
opposite the drive. For clockwise rotation, interchange A1 and A2.
Some manufacturers connect the interpole winding on the A2 side
of the armature.
When the shunt field is separately excited, the same polarities
must be observed for a given rotation.
10
TERMINAL MARKINGS AND CONNECTIONS
FOR DC GENERATORS (NEMA NOMENCLATURE)
SHUNT GENERATOR
SHUNT FIELD
INTERPOLES
F1
+
A1
ARMATURE
LINE
-
A2
F2
LINE
COMPOUND GENERATOR
SHUNT FIELD
INTERPOLES
F1
+ A1
ARMATURE
A2
LINE
SERIES
FIELD
S1
S2
-
F2
LINE
All connections are for counterclockwise rotation facing the end
opposite the drive. For clockwise rotation, interchange A1 and
A2.
Some manufacturers connect the interpole winding on the A2
side of the armature.
For the above generators, the shunt field may be either selfexcited or separately excited. When it is self-excited, connections
should be made as shown by the dotted lines. When the shunt
field is separately excited, it is usually isolated from the other
windings of the machine, but the polarity or the voltage applied
to the shunt field should be as shown for the particular rotation
and armature polarity.
NEMA MG 1-1998 (Rev. 3), 2.14, Note 5.
11
FULL-LOAD CURRENTS OF DC MOTORS*
(RUNNING AT BASE SPEED)
*For conductor slzlng only.
FULL-LOAD CURRENT IN AMPERES†
HP
.25
.33
.5
.75
1
1.5
2
3
5
7.5
10
15
20
25
30
40
50
60
75
100
125
150
200
90V
4.0
5.2
6.8
9.6
12.2
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
RATED ARMATURE VOLTAGE
120V
180V
240V
500V
3.1
2.0
1.6
—
4.1
2.6
2.0
—
5.4
3.4
2.7
—
7.6
4.8
3.8
—
9.5
6.1
4.7
—
13.2
8.3
6.6
—
17
10.8
8.5
—
25
16
12.2
—
40
27
20
—
58
—
29
13.6
76
—
38
18
—
—
55
27
—
—
72
34
—
—
89
43
—
—
106
51
—
—
140
67
—
—
173
83
—
—
206
99
—
—
255
123
—
—
341
164
—
—
425
205
—
—
506
246
—
—
675
330
550V
—
—
—
—
—
—
—
—
—
12.2
16
24
31
38
46
61
75
90
111
148
185
222
294
OVER 200 HP
Approx.
Amps/hp
—
—
—
3.4
1.7
1.5
†These are average direct-current quantities.
Branch-circuit conductors supplying a single motor shall have an ampacity
not less than 125 percent of the motor full-load current rating.
Armature current varies inversely as applied voltage.
Example: 40 hp motor, 300 volt armature
240
Armature current =140 x ––– = 112 amps
300
The above table is based on Table 430.147 of the National Electrical
®
Code , 2002. National Electrical Code® and NEC® are registered trade
marks of the National Fire Protection Association, Inc. Quincy, MA 02269.
13
FULL-LOAD CURRENTS
THREE-PHASE SQUIRREL CAGE
AND WOUND-ROTOR MOTORS*
*For conductor sizing only
FULL-LOAD CURRENT IN AMPERES
HP
.5
.75
1
1.5
2
3
5
7.5
10
15
20
25
30
40
50
60
75
100
125
150
200
250
300
350
400
450
500
200V
2.5
3.7
4.8
6.9
7.8
11.0
17.5
25.3
32.2
48.3
62.1
78.2
92
120
150
177
221
285
359
414
552
—
—
—
—
—
—
208V
2.4
3.5
4.6
6.6
7.5
10.6
16.7
24.2
30.8
46.2
59.4
74.8
88
114
143
169
211
273
343
396
528
—
—
—
—
—
—
230V
2.2
3.2
4.2
6.0
6.8
9.6
15.2
22
28
42
54
68
80
104
130
154
192
248
312
360
480
—
—
—
—
—
—
460V
1.1
1.6
2.1
3.0
3.4
4.8
7.6
11
14
21
27
34
40
52
65
77
96
124
156
180
240
302
361
414
477
515
590
575V
0.9
1.3
1.7
2.4
2.7
3.9
6.1
9
11
17
22
27
32
41
52
62
77
99
125
144
192
242
289
336
382
412
472
2.64
2.4
1.2
.96
2300V 4000V
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
16
9
20
11
26
14
31
18
37
21
49
28
60
35
72
41
83
48
95
55
103
59
118
68
OVER 200 HP
Approx.
Amps/hp
2.75
.24
.14
Branch-circuit conductors supplying a single motor shall have an
ampacity not less than 125 percent of the motor full-load current rating.
Based on Table 430.150 of the National Electrical Code,® 2002.
14
FULL-LOAD CURRENTS
THREE-PHASE SYNCHRONOUS MOTORS (UNITY
POWER FACTOR) AND SINGLE-PHASE MOTORS*
*For conductor sizing only
THREE-PHASE SYNCHRONOUS MOTORS
FULL-LOAD CURRENT IN AMPERES
HP
100
125
150
200
250
300
460V
100
125
150
200
250
300
RATED VOLTAGE
575V
2300V
80
20
100
25
120
30
160
40
200
50
240
60
350
400
500
600
700
800
900
1000
353
403
500
600
705
805
905
960
282
322
400
480
564
644
724
768
71
80
100
120
141
161
181
192
4000V
12
14
17
23
29
35
41
46
58
69
81
93
104
110
SINGLE-PHASE MOTORS
FULL-LOAD CURRENT IN AMPERES
RATED VOLTAGE
HP
.167
.25
.34
.5
.75
1
1.5
2
3
5
7.5
10
115V
4.4
5.8
7.2
9.8
13.8
16
20
24
34
56
80
100
200V
2.5
3.3
4.1
5.6
7.9
9.2
11.5
13.8
19.6
32.2
46
57.5
208V
2.4
3.2
4.0
5.4
7.6
8.8
11
13.2
18.7
30.8
44
55
230V
2.2
2.9
3.6
4.9
6.9
8
10
12
17
28
40
50
Branch-circuit conductors supplying a single motor shall have an ampacity
not less than 125 percent of the motor full-load current rating.
Based on Table 430.148 of the National Electrical Code®, 2002.
15
MAXIMUM LOCKED-ROTOR CURRENTS
THREE-PHASE SQUIRREL CAGE MOTORS
NEMA DESIGNS B, C AND D
LOCKED-ROTOR CURRENT IN AMPERES
RATED VOLTAGE, 60 Hz
HP
200V
230V
1
23
29
34
20
25
30
10
12
15
8
10
12
1.5
2
3
46
57
74
40
50
64
20
25
32
16
20
26
5
7.5
10
106
146
186
92
127
162
46
63
81
37
51
65
15
20
25
267
333
420
232
290
365
116
145
182
93
116
146
30
40
50
500
667
834
435
580
725
217
290
362
174
232
290
60
75
100
1000
1250
1665
870
1085
1450
435
542
725
348
434
580
87
108
145
50
62
83
125
150
200
2085
2500
3335
1815
2170
2900
907
1085
1450
726
868
1160
181
217
290
104
125
167
250
300
350
4200
5060
5860
3650
4400
5100
1825
2200
2550
1460
1760
2040
365
440
510
210
253
293
400
450
500
6670
7470
8340
5800
6500
7250
2900
3250
3625
2320
2600
2900
580
650
725
333
374
417
.5
.75
460V
575V
2300V 4000V
The locked-rotor current of Design B, C and D constant-speed induction
motors, when measured with rated voltage and frequency impressed
and with rotor locked, shall not exceed the above values.
Reference: NEMA MG 1-1998 (Rev. 3), 12.35.1. See NEMA MG 1-1998
(Rev. 3), 12.35.3 for 50 Hz, 380 volts.
16
GENERAL SPEED-TORQUE
CHARACTERISTICS
THREE-PHASE INDUCTION MOTORS
100
Speed (% of synchronous speed)
Design D
(5 % slip)
80
60
Design A
40
Design C
Design B
20
0
0
50
100
150
200
250
300
Torque (% of full-load torque)
NEMA
DESIGN
LOCKED
ROTOR
TORQUE
LOCKED
BREAKDOWN ROTOR
TORQUE
CURRENT
SLIP
RELATIVE
EFFICIENCY
B
70 - 275%*
175 - 300%*
600 - 800% 0.5-5% Medium
or High
Applications: Fans, blowers, centrifugal pumps and compressors,
motor-generator sets, etc., where starting torque requirements are
relatively low.
C
200 - 250%*
190 - 225%*
600 - 800% 1-5%
Medium
Applications: Conveyors, crushers, stirring machines, agitators,
reciprocating pumps and compressors, etc., where starting under
load is required.
D
275%
275%
600 - 800% ≥5%
Medium
Applications: High peak loads with or without flywheels, such as
punch presses, shears,elevators, extractors, winches, hoists, oil-well
pumping, and wire-drawing machines.
Based on NEMA MG 10-2001, Table 1. NEMA Design A is a variation of Design B
having higher locked-rotor current.
*Higher values are for motors having lower horsepower ratings.
17
FULL-LOAD EFFICIENCIES
THREE-PHASE, SQUIRREL CAGE, ENERGY
EFFICIENT OPEN MOTORS (NEMA DESIGNS A AND B)
2 POLE
HP
1.0
1.5
2.0
3.0
5.0
7.5
10.0
15.0
20.0
25.0
30.0
40.0
50.0
60.0
75.0
100.0
125.0
150.0
200.0
250.0
300.0
350.0
400.0
450.0
500.0
NOMINAL
EFFICIENCY
82.5
84.0
84.0
85.5
87.5
88.5
89.5
90.2
91.0
91.0
91.7
92.4
93.0
93.0
93.0
93.6
93.6
94.5
94.5
95.0
95.0
95.4
95.8
95.8
4 POLE
6 POLE
MINIMUM
NOMINAL
MINIMUM
NOMINAL
EFFICIENCY EFFICIENCY EFFICIENCY EFFICIENCY
80.0
81.5
81.5
82.5
85.5
86.5
87.5
88.5
89.5
89.5
90.2
91.0
91.7
91.7
91.7
92.4
92.4
93.6
93.6
94.1
94.1
94.5
95.0
95.0
82.5
84.0
84.0
86.5
87.5
88.5
89.5
91.0
91.0
91.7
92.4
93.0
93.0
93.6
94.1
94.1
94.5
95.0
95.0
95.4
95.4
95.4
95.4
95.8
95.8
80.0
81.5
81.5
84.0
85.5
86.5
87.5
89.5
89.5
90.2
91.0
91.7
91.7
92.4
93.0
93.0
93.6
94.1
94.1
94.5
94.5
94.5
94.5
95.0
95.0
80.0
84.0
85.5
86.5
87.5
88.5
90.2
90.2
91.0
91.7
92.4
93.0
93.0
93.6
93.6
94.1
94.1
94.5
94.5
95.4
95.4
95.4
MINIMUM
EFFICIENCY
77.0
81.5
82.5
84.0
85.5
86.5
88.5
88.5
89.5
90.2
91.0
91.7
91.7
92.4
92.4
93.0
93.0
93.6
93.6
94.5
94.5
94.5
The full load efficiency of Design A and B motors rated 600 volts or less,
when operating at rated voltage and frequency, shall not be less than the
minimum efficiency listed in the table above for the motor to be classified
as “energy efficient.” Nominal efficiency represents a value which should
be used to compute the energy consumption of a motor or group of motors.
Reference: NEMA MG 1-1998 (Rev. 3), 12.60, Table 12-11.
The Energy Policy Act of 1992 (USA): The nominal full-load efficiency of
electric motors as specified in the Energy Policy Act of 1992 is the same
as that listed in the table for 1.0 to 200.0 hp motors.
18
FULL-LOAD EFFICIENCIES
THREE-PHASE, SQUIRREL CAGE, ENERGY EFFICIENT
ENCLOSED MOTORS (NEMA DESIGNS A AND B)
2 POLE
HP
4 POLE
NOMINAL
MINIMUM
NOMINAL
EFFICIENCY EFFICIENCY EFFICIENCY
6 POLE
MINIMUM
NOMINAL
MINIMUM
EFFICIENCY EFFICIENCY EFFICIENCY
1.0
1.5
2.0
75.5
82.5
84.0
72.0
80.0
81.5
82.5
84.0
84.0
80.0
81.5
81.5
80.0
85.5
86.5
77.0
82.5
84.0
3.0
5.0
7.5
85.5
87.5
88.5
82.5
85.5
86.5
87.5
87.5
89.5
85.5
85.5
87.5
87.5
87.5
89.5
85.5
85.5
87.5
10.0
15.0
20.0
89.5
90.2
90.2
87.5
88.5
88.5
89.5
91.0
91.0
87.5
89.5
89.5
89.5
90.2
90.2
87.5
88.5
88.5
25.0
30.0
40.0
91.0
91.0
91.7
89.5
89.5
90.2
92.4
92.4
93.0
91.0
91.0
91.7
91.7
91.7
93.0
90.2
90.2
91.7
50.0
60.0
75.0
92.4
93.0
93.0
91.0
91.7
91.7
93.0
93.6
94.1
91.7
92.4
93.0
93.0
93.6
93.6
91.7
92.4
92.4
100.0
125.0
150.0
93.6
94.5
94.5
92.4
93.6
93.6
94.5
94.5
95.0
93.6
93.6
94.1
94.1
94.1
95.0
93.0
93.0
94.1
200.0
250.0
300.0
95.0
95.4
95.4
94.1
94.5
94.5
95.0
95.0
95.4
94.1
94.1
94.5
95.0
95.0
95.0
94.1
94.1
94.1
350.0
400.0
450.0
500.0
95.4
95.4
95.4
95.4
94.5
94.5
94.5
94.5
95.4
95.4
95.4
95.8
94.5
94.5
94.5
95.0
95.0
94.1
The full load efficiency of Design A and B motors rated 600 volts or less,
when operating at rated voltage and frequency, shall not be less than the
minimum efficiency listed in the table above for the motor to be classified
as “energy efficient.” Nominal efficiency represents a value which should
be used to compute the energy consumption of a motor or group of motors.
Reference: NEMA MG 1-1998 (Rev. 3), 12.60, Table 12-11.
The Energy Policy Act of 1992 (USA): The nominal full-load efficiency of
electric motors as specified in the Energy Policy Act of 1992 is the same
as that listed in the table for 1.0 to 200.0 hp motors.
19
24
NEMA FRAME ASSIGNMENTS
HP
326
364S
20
25
225
254
5
7.5
284
324
204
224
2
3
10
15
—
203
ORIG.
1
1.5
NEMA
PROGRAM
284U
286U
254U
256U
213
215
184
184
—
182
254T
256T
213T
215T
182T
184T
145T
145T
—
143T
364
364
324
326
254
284
224
225
203
204
286U
324U
256U
284U
215
254U
184
213
182
184
1952
RERATE
1952
RERATE
ORIG.
1800 RPM
3600 RPM
1964
RERATE
256T
284T
215T
254T
184T
213T
145T
182T
143T
145T
1964
RERATE
365
404
326
364
284
324
225
254
204
224
ORIG.
THREE-PHASE OPEN MOTORS—GENERAL PURPOSE
1200 RPM
326U
364U
284U
324U
254U
256U
213
215
184
184
1952
RERATE
286T
324T
256T
284T
215T
254T
184T
213T
145T
182T
1964
RERATE
404
405
364
365
324
326
254
284
225
254
ORIG.
900 RPM
364U
365U
286U
326U
256U
284U
215
254U
213
213
1952
RERATE
324T
326T
284T
286T
254T
256T
213T
215T
182T
184T
1964
RERATE
25
†
404S
405S
444S
445S
504S
505S
—
—
50
60
75
100
125
150
200
250
—
—
444US
445US
404US
405US
364US
365US
324S
326S
444TS
445TS
404TS
405TS
364TS
365TS
324TS
326TS
284TS
286TS
—
—
505S
—
445S
504S
405S
444S
365
404
—
—
445US
—
405US
444US
365US
404US
326U
364U
445
504U
505
—
—
—
—
—
365TS†
404TS†
405TS†
444TS†
445TS†
—
405
444
326T
364TS†
286T
324T
—
—
—
—
445U
—
405U
444U
365U
404U
—
—
445T
—
405T
444T
365T
404T
326T
364T
—
—
—
—
—
—
504U
505
444
445
—
—
—
—
—
—
444U
445U
404U
405U
—
—
—
—
444T
445T
404T
405T
364T
365T
When motors are to be used with V-belts or chain drive, the correct frame size is the one shown but with the suffix letter S
omitted. For the corresponding shaft extension dimensions, see Pages 28-31.
364S
365S
30
40
26
NEMA FRAME ASSIGNMENTS
—
203
204
224
225
254
2
3
5
7.5
ORIG.
1
1.5
254U
256U
286U
326
365S 324U
20
25
284TS
256T
215T
254T
184T
213T
182T
213
215
145T
184
—
143T
184
—
182
3600 RPM
1952
1964
RERATE RERATE
284
324
10
15
HP
NEMA
PROGRAM
365
364
324
326
254
284
225
224
203
204
324U
286U
256U
284U
215
254U
213
184
182
184
284T
256T
215T
254T
184T
213T
182T
145T
143T
145T
1800 RPM
1952
1964
ORIG. RERATE RERATE
THREE-PHASE TEFC MOTORS—GENERAL PURPOSE
404
365
326
364
284
324
254
225
204
224
ORIG.
364U
326U
284U
324U
254U
256U
215
213
184
184
324T
286T
256T
284T
215T
254T
213T
184T
145T
182T
1200 RPM
1952
1964
RERATE RERATE
405
404
364
365
324
326
284
254
225
254
ORIG.
365U
364U
286U
326U
256U
284U
254U
215
213
213
326T
324T
284T
286T
254T
256T
213T
215T
182T
184T
900 RPM
1952
1964
RERATE RERATE
27
365TS
445S 405US
504S 444US
505S 445US
—
—
60
75
100
125
150
445TS
444TS
405TS
326TS
364U
326U
—
—
—
—
505S 445US
504S 444US
445S 405US
444S 365US
405
404
445TS†
444TS†
405TS†
365TS†
364TS†
326T
324T
286T
—
—
—
505
504U
445
444
405
—
—
—
445U
444U
405U
404U
365U
—
445T
444T
405T
404T
365T
364T
326T
—
—
—
—
505
504U
445
444
—
—
—
—
445U
444U
405U
404U
—
—
445T
444T
405T
404T
365T
364T
†When motors are to be used with V-belt or chain drives, the correct frame size is the frame size shown but with the suffix letter
S omitted. For the corresponding shaft extension dimensions, see Pages 28-31.
—
—
364TS
444S 365US
50
324TS
286TS
404S 326S
405S 364US
30
40
NEMA FRAME DIMENSIONS*
FOOT-MOUNTED DC MACHINES
D
2F
B
E
BA
E
H
A
* Dimensions in inches
FRAME
A MAX
D
E
2F
BA
H
6.75
7.25
7.75
8.25
2.62
3.00
3.50
3.50
3.50
3.50
3.50
3.50
1.75
2.12
2.44
2.44
2.75
2.75
2.75
2.75
1.69
2.75
3.00
5.00
3.50
4.00
4.50
5.00
2.06
2.50
2.75
2.75
2.75
2.75
2.75
2.75
0.28
0.34
0.34
0.34
0.34
0.34
0.34
0.34
7.00
7.00
7.00
7.00
8.75
9.50
10.25
11.25
3.50
3.50
3.50
3.50
2.75
2.75
2.75
2.75
5.50
6.25
7.00
8.00
2.75
2.75
2.75
2.75
0.34
0.34
0.34
0.34
1410AT
1411AT
1412AT
162AT
7.00
7.00
7.00
8.00
12.25
13.25
14.25
6.00
3.50
3.50
3.50
4.00
2.75
2.75
2.75
3.12
9.00
10.00
11.00
4.00
2.75
2.75
2.75
2.50
0.34
0.34
0.34
0.41
163AT
164AT
165AT
166AT
8.00
8.00
8.00
8.00
6.50
7.00
7.50
8.20
4.00
4.00
4.00
4.00
3.12
3.12
3.12
3.12
4.50
5.00
5.50
6.25
2.50
2.50
2.50
2.50
0.41
0.41
0.41
0.41
167AT
168AT
169AT
1610AT
8.00
8.00
8.00
8.00
9.00
10.00
11.00
12.00
4.00
4.00
4.00
4.00
3.12
3.12
3.12
3.12
7.00
8.00
9.00
10.00
2.50
2.50
2.50
2.50
0.41
0.41
0.41
0.41
182AT
183AT
184AT
185AT
9.00
9.00
9.00
9.00
6.50
7.00
7.50
8.25
4.50
4.50
4.50
4.50
3.75
3.75
3.75
3.75
4.50
5.00
5.50
6.25
2.75
2.75
2.75
2.75
0.41
0.41
0.41
0.41
186AT
187AT
188AT
189AT
9.00
9.00
9.00
9.00
9.00
10.00
11.00
12.00
4.50
4.50
4.50
4.50
3.75
3.75
3.75
3.75
7.00
8.00
9.00
10.00
2.75
2.75
2.75
2.75
0.41
0.41
0.41
0.41
1810AT
213AT
214AT
215AT
9.00
10.50
10.50
10.50
13.00
7.50
8.25
9.00
4.50
5.25
5.25
5.25
3.75
4.25
4.25
4.25
11.00
5.50
6.25
7.00
2.75
3.50
3.50
3.50
0.41
0.41
0.41
0.41
216AT
217AT
218AT
219AT
10.50
10.50
10.50
10.50
10.00
11.00
12.00
13.00
5.25
5.25
5.25
5.25
4.25
4.25
4.25
4.25
8.00
9.00
10.00
11.00
3.50
3.50
3.50
3.50
0.41
0.41
0.41
0.41
2110AT
253AT
254AT
255AT
10.50
12.50
12.50
12.50
14.50
9.50
10.75
11.50
5.25
6.25
6.25
6.25
4.25
5.00
5.00
5.00
12.50
7.00
8.25
9.00
3.50
4.25
4.25
4.25
0.41
0.53
0.53
0.53
256AT
257AT
258AT
259AT
12.50
12.50
12.50
12.50
12.50
13.50
15.00
16.50
6.25
6.25
6.25
6.25
5.00
5.00
5.00
5.00
10.00
11.00
12.50
14.00
4.25
4.25
4.25
4.25
0.53
0.53
0.53
0.53
42
48
56
56H
142AT
143AT
144AT
145AT
7.00
7.00
7.00
7.00
146AT
147AT
148AT
149AT
44
B MAX
NEMA FRAME DIMENSIONS*
FOOT-MOUNTED DC MACHINES–CONTINUED
* Dimensions in inches
FRAME
283AT
284AT
285AT
286AT
287AT
288AT
289AT
323AT
324AT
325AT
326AT
327AT
328AT
329AT
363AT
364AT
365AT
366AT
367AT
368AT
369AT
403AT
404AT
405AT
406AT
407AT
408AT
409AT
443AT
444AT
445AT
446AT
447AT
448AT
449AT
502AT
503AT
504AT
505AT
506AT
507AT
508AT
509AT
583A
584A
585A
586A
587A
588A
683A
684A
685A
686A
687A
688A
A MAX
14.00
14.00
14.00
14.00
14.00
14.00
14.00
16.00
16.00
16.00
16.00
16.00
16.00
16.00
18.00
18.00
18.00
18.00
18.00
18.00
18.00
20.00
20.00
20.00
20.00
20.00
20.00
20.00
22.00
22.00
22.00
22.00
22.00
22.00
22.00
25.00
25.00
25.00
25.00
25.00
25.00
25.00
25.00
29.00
29.00
29.00
29.00
29.00
29.00
34.00
34.00
34.00
34.00
34.00
34.00
B MAX
11.00
12.50
13.00
14.00
15.50
17.00
19.00
12.50
14.00
14.50
15.50
17.50
19.50
21.50
14.00
15.25
16.25
18.00
20.00
22.00
24.00
15.00
16.25
17.75
20.00
22.00
24.00
26.00
16.50
18.50
20.50
22.00
24.00
26.00
29.00
17.50
19.00
21.00
23.00
25.00
27.00
30.00
33.00
21.00
23.00
25.00
27.00
30.00
33.00
25.00
27.00
30.00
33.00
37.00
41.00
D
7.00
7.00
7.00
7.00
7.00
7.00
7.00
8.00
8.00
8.00
8.00
8.00
8.00
8.00
9.00
9.00
9.00
9.00
9.00
9.00
9.00
10.00
10.00
10.00
10.00
10.00
10.00
10.00
11.00
11.00
11.00
11.00
11.00
11.00
11.00
12.50
12.50
12.50
12.50
12.50
12.50
12.50
12.50
14.50
14.50
14.50
14.50
14.50
14.50
17.00
17.00
17.00
17.00
17.00
17.00
E
5.50
5.50
5.50
5.50
5.50
5.50
5.50
6.25
6.25
6.25
6.25
6.25
6.25
6.25
7.00
7.00
7.00
7.00
7.00
7.00
7.00
8.00
8.00
8.00
8.00
8.00
8.00
8.00
9.00
9.00
9.00
9.00
9.00
9.00
9.00
10.00
10.00
10.00
10.00
10.00
10.00
10.00
10.00
11.50
11.50
11.50
11.50
11.50
11.50
13.50
13.50
13.50
13.50
13.50
13.50
2F
8.00
9.50
10.00
11.00
12.50
14.00
16.00
9.00
10.50
11.00
12.00
14.00
16.00
18.00
10.00
11.25
12.25
14.00
16.00
18.00
20.00
11.00
12.25
13.75
16.00
18.00
20.00
22.00
12.50
15.00
16.50
18.00
20.00
22.00
25.00
12.50
14.00
16.00
18.00
20.00
22.00
25.00
28.00
16.00
18.00
20.00
22.00
25.00
28.00
20.00
22.00
25.00
28.00
32.00
36.00
BA
4.75
4.75
4.75
4.75
4.75
4.75
4.75
5.25
5.25
5.25
5.25
5.25
5.25
5.25
5.88
5.88
5.88
5.88
5.88
5.88
5.88
6.62
6.62
6.62
6.62
6.62
6.62
6.62
7.50
7.50
7.50
7.50
7.50
7.50
7.50
8.50
8.50
8.50
8.50
8.50
8.50
8.50
8.50
10.00
10.00
10.00
10.00
10.00
10.00
11.50
11.50
11.50
11.50
11.50
11.50
H†
0.53
0.53
0.53
0.53
0.53
0.53
0.53
0.66
0.66
0.66
0.66
0.66
0.66
0.66
0.81
0.81
0.81
0.81
0.81
0.81
0.81
0.94
0.94
0.94
0.94
0.94
0.94
0.94
1.06
1.06
1.06
1.06
1.06
1.06
1.06
1.19
1.19
1.19
1.19
1.19
1.19
1.19
1.19
1.19
1.19
1.19
1.19
1.19
1.19
1.19
1.19
1.19
1.19
1.19
1.19
References and tolerances on dimensions: NEMA MG 1-1998 (Rev. 3), 4.5.1, 4.5.2,
4.5.3 and 4.9.
† Frames 42 to 56H, inclusive—The H dimension is Width of Slot. Frames 142AT to 688A,
inclusive—The H dimension is Diameter of Hole.
45
66
NEMA SIZE STARTERS
00
0
1
2
3
4
5
6
7
8
9
NEMA
SIZE
1.5
3
7.5
10
25
40
75
150
—
—
—
1.5
2
3
5
7.5
10
15
25
30
50
50
100
100
200
200
400
300
600
450
900
800
1600
—
—
7.5
10
25
40
75
150
—
—
—
—
—
7.5
15
30
50
100
200
300
450
800
230V
—
—
10
25
50
100
200
400
600
900
1600
460V
575V
200V
460V
575V
200V
230V
AUTOTRANSFORMER
STARTING
FULL VOLTAGE
STARTING
—
—
10
20
40
75
150
—
—
—
—
200V
—
—
10
25
50
75
150
300
450
700
1300
230V
—
—
15
40
75
150
350
600
900
1400
2600
460V
575V
PART-WINDING
STARTING
MAXIMUM HORSEPOWER—THREE-PHASE MOTORS
FOR THREE-PHASE MOTORS
—
—
10
20
40
60
150
300
500
750
1500
200V
—
—
10
25
50
75
150
350
500
800
1500
230V
WYE-DELTA
STARTING
—
—
15
40
75
150
300
700
1000
1500
3000
460V
575V
STARTER ENCLOSURES
TYPE
NEMA ENCLOSURE
1
2
3
3R
3S
4
4X
5
6
General Purpose—Indoor
Dripproof—Indoor
Dusttight, Raintight, Sleettight—Outdoor
Raintight, Sleet Resistant—Outdoor
Dusttight, Raintight, Sleettight—Outdoor
Watertight, Dusttight, Sleet Resistant—Indoor & Outdoor
Watertight, Dusttight, Corrosion-Resistant—Indoor & Outdoor
Dusttight, Dripproof—Indoor
Occasionally Submersible, Watertight, Sleet Resistant—
Indoor & Outdoor
Watertight, Sleet Resistant—Prolonged Submersion—
Indoor & Outdoor
Dusttight and Driptight—Indoor
Dusttight and Driptight, with Knockouts—Indoor
Oiltight and Dusttight—Indoor
HAZARDOUS LOCATION STARTERS
Class I, Group A, B, C or D Hazardous
Locations—Indoor
Class I, Group A, B, C or D Hazardous Locations—
Indoor & Outdoor
Class II, Group E, F or G Hazardous Locations—Indoor
Requirements of Mine Safety and Health
Administration
6P
12
12K
13
7
8
9
10
CONVERSION OF NEMA TYPE NUMBERS
TO IEC CLASSIFICATION DESIGNATIONS
(Cannot be used to convert IEC Classification Designations to NEMA Type Numbers)
NEMA ENCLOSURE
TYPE NUMBER
1
2
3
3R
3S
4 and 4X
5
6 and 6P
12 and 12K
13
IEC ENCLOSURE
CLASSIFICATION DESIGNATION
IP10
IP11
IP54
IP14
IP54
IP56
IP52
IP67
IP52
IP54
Note: This comparison is based on tests specified in IEC Publication 60529 (2001-02).
Reference: Information in the above tables is based on NEMA 250-1997.
67
NEMA SIZE STARTERS
FOR SINGLE-PHASE MOTORS
SIZE OF
CONTROLLER
CONTINUOUS
CURRENT
RATING
(AMPERES)
00
0
1
1P
2
3
9
18
27
36
45
90
HORSEPOWER
AT
AT
115V
230V
1
/3
1
2
3
3
71/2
1
2
3
5
71/2
15
Reference: NEMA ICS2-1993, Table 2-4-2.
DERATING FACTORS FOR
CONDUCTORS IN A CONDUIT (PAGES 70 - 72)
NUMBER OF
CURRENT CARRYING
CONDUCTORS
PERCENT OF VALUES IN
TABLES AS 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 70-2002, National Electrical
Code,® copyright © 2002, National Fire Protection Association, Quincy,
Massachusetts 02269.
69
COMMON FRACTIONS OF AN INCH
DECIMAL AND METRIC EQUIVALENTS
FRACTION
1/64
1/32
3/64
1/16
5/64
3/32
7/64
1/8
9/64
5/32
11/64
3/16
13/64
7/32
15/64
1/4
17/64
9/32
19/64
5/16
21/64
11/32
23/64
3/8
25/64
13/32
27/64
7/16
29/64
15/32
31/64
1/2
DECIMAL mm
0.01562
0.03125
0.04688
0.397
0.794
1.191
0.06250
0.07812
0.09375
1.588
1.984
2.381
0.10938
0.12500
0.14062
2.778
3.175
3.572
0.15625
0.17188
0.18750
3.969
4.366
4.763
0.20312
0.21875
0.23438
5.159
5.556
5.953
0.25000
0.26562
0.28125
6.350
6.747
7.144
0.29688
0.31250
0.32812
7.541
7.938
8.334
0.34375
0.35938
0.37500
8.731
9.128
9.525
0.39062
0.40625
0.42188
9.922
10.319
10.716
0.43750
0.45312
0.46875
11.113
11.509
11.906
0.48438
0.50000
12.303
12.700
FRACTION
33/64
17/32
35/64
9/16
37/64
19/32
39/64
5/8
41/64
21/32
43/64
11/16
45/64
23/32
47/64
3/4
49/64
25/32
51/64
13/16
53/64
27/32
55/64
7/8
57/64
29/32
59/64
15/16
61/64
31/32
63/64
1/1
DECIMAL mm
0.51562
0.53125
0.54688
13.097
13.494
13.891
0.56250
0.57812
0.59375
14.288
14.684
15.081
0.60938
0.62500
0.64062
15.478
15.875
16.272
0.65625
0.67188
0.68750
16.669
17.066
17.463
0.70312
0.71875
0.73438
17.859
18.256
18.653
0.75000
0.76562
0.78125
19.05
19.447
19.844
0.79688
0.81250
0.82812
20.241
20.638
21.034
0.84375
0.85938
0.87500
21.431
21.828
22.225
0.89062
0.90625
0.92188
22.622
23.019
23.416
0.93750
0.95312
0.96875
23.813
24.209
24.606
0.98438
1.00000
25.003
25.400
97
USEFUL FORMULAS
FORMULAS FOR ELECTRIC MOTORS
TO FIND
Horsepower
DIRECT
CURRENT
SINGLE PHASE
E x I x EFF
746
E x I x EFF x PF
746
Current
Efficiency
THREE PHASE
1.732 x E x I x EFF x PF
746
746 x hp
746 x hp
746 x hp
E x EFF
E x EFF x PF
1.732 x E x EFF x PF
746 x hp
E x I
746 x hp
E x I x PF
746 x hp
1.732 x E x I x PF
Input watts
E x I
Input watts
1.732 x E x I
Power
Factor
E
= Volts
EFF = Efficiency (decimal)
hp
= Horsepower
I
PF
= Amperes
= Power factor (decimal)
FORMULAS FOR ELECTRICAL CIRCUITS
TO FIND
DIRECT
CURRENT
Watts
Volts
Amperes
VoltAmperes
Watts
Volts x Amperes
SINGLE PHASE
Watts
Volts x Power factor
THREE PHASE
Watts
1.732 x Volts x Power factor
Volts x Amperes
1.732 x Volts x Amperes
Volts x Amperes
x Power factor
1.732 x Volts x Amperes
x Power factor
OHMS LAW
Ohms = Volts/Amperes (R = E/I)
CAPACITANCE IN MICROFARADS
AT 60 HZ
Capacitance
=
2650 x Amperes
Volts
Capacitance
=
2.65 x kVAR
(Volts)2
Amperes = Volts/Ohms (I = E/R)
Volts
98
= Amperes x Ohms (E = IR)
USEFUL FORMULAS
TEMPERATURE CORRECTION OF
WINDING RESISTANCE
RC = RH x
RH = RC x
(K + TC)
(K + TH)
RC
VALUE OF K
Material
K
(K + TH)
Aluminum
225
(K + TC)
Copper
234.5
=
Resistance at temperature
TC (Ohms)
RH = Resistance at temperature
TH (Ohms)
TC = Temperature of cold
winding (° C)
TH = Temperature of hot
winding (° C)
MOTOR APPLICATION FORMULAS
OUTPUT
Horsepower =
Torque (lb.ft) x rpm
5252
Kilowatts
Torque (lb.ft) =
Horsepower x 5252
rpm
Torque (N.m) =
=
Torque (N.m) x rpm
9550
Kilowatts x 9550
rpm
For approximation, use:
Full-load torque = 1.5 ft•lb per hp per pole pair at 60 Hz
Full-load torque = 3.2 N•m per kilowatt per pole pair at 50 hZ
TIME FOR MOTOR TO REACH OPERATING SPEED
Seconds =
Wk 2 (lb • ft 2 ) × Speed change (rpm)
308 × Avg. accelerating torque (lb • ft)
Seconds =
1 kg • m2 = 23.73 lb • ft 2
J(kg • m ) × Speed change (rpm)
9.55 × Avg. accelerating torque (N • m)
1 lb • ft 2 = .04214 kg • m2
2
Wk2
J
load × Load rpm
} = Inertia of rotor + Inertia ofMotor
rpm
Average accelerating torque =
Where: BDT =
FLT =
LRT =
2
2
[(FLT + BDT)/2] + BDT + LRT
3
Breakdown torque
Full-load torque
Locked-rotor torque
99
CONVERSION FACTORS
Length
Area
BY
x
x
x
x
x
x
x
x
x
x
x
x
x
Circular mils
Circular mils
Square centimeters
Square feet
Square feet
Square inches
Square meters
Square meters
Square millimeters
Square mils
Square yards
x
x
x
x
x
x
x
x
x
x
x
Volume
MULTIPLY
Centimeters
Feet
Feet
Inches
Inches
Kilometers
Meters
Meters
Meters
Miles
Miles
Millimeters
Yards
Cubic centimeters
Cubic feet
Cubic feet
Cubic inches
Cubic meters
Cubic meters
Cubic meters
Cubic yards
Gallons
Gallons
Liters
Liters
Ounces (fluid)
Quarts (liquid)
x
x
x
x
x
x
x
x
x
x
x
x
x
x
104
.3937
12.0
.3048
2.54
25.4
.6214
3.281
39.37
1.094
5280.0
1.609
.03937
.9144
TO OBTAIN
=
=
=
=
=
=
=
=
=
=
=
=
=
Inches
Inches
Meters
Centimeters
Millimeters
Miles
Feet
Inches
Yards
Feet
Kilometers
Inches
Meters
7.854x10-7
.7854
.155
144.0
.0929
6.452
10.764
1.196
.00155
1.273
.8361
=
=
=
=
=
=
=
=
=
=
=
Square inches
Square mils
Square inches
Square inches
Square meters
Square centimeters
Square feet
Square yards
Square inches
Circular mils
Square meters
.061
.0283
7.481
.5541
35.31
1.308
264.2
.7646
.1337
3.785
.2642
1.057
1.805
.9463
=
=
=
=
=
=
=
=
=
=
=
=
=
=
Cubic inches
Cubic meters
Gallons
Ounces (fluid)
Cubic feet
Cubic yards
Gallons
Cubic meters
Cubic feet
Liters
Gallons
Quarts (liquid)
Cubic inches
Liters