|
Electrical
motors present special electrical startup considerations. They can require
up to three times their rated running wattage to start. Motor nameplates
generally will show starting watts, some as high as nine times the running
wattage. Check the nameplate to be sure.
Be certain to use the starting watts when
figuring the correct electrical load requirements.
If you don't have enough power to start you won't have enough to run.
Motor
load requirements are listed below:
|
Motor Rating
HP
|
Approximate Running
Watts
|
Universal Motors
Small Appliance
|
Reduction Induction
Motors
|
Capacitor Motors
|
|
1/8
|
275
|
400
|
600
|
850
|
|
1/4
|
400
|
500
|
850
|
1050
|
|
1/3
|
450
|
600
|
975
|
1350
|
|
1/2
|
600
|
750
|
1300
|
1800
|
|
3/4
|
850
|
1000
|
1900
|
2600
|
|
1
|
1000
|
1250
|
2300
|
3000
|
|
1-1/2
|
1600
|
1750
|
3200
|
4200
|
|
2
|
2000
|
2350
|
3900
|
5100
|
|
3**
|
3000
|
3550
|
5200
|
6800
|
|
** Motors of higher
HP are not generally used.
|
WATER WELL
PUMP kW / kVA REQUIREMENTS
|
Pump Rating
|
Externally Regulated
Generator
|
Internally Regulated
Generator
|
|
HP
|
Min.
kW
|
Min.
kVA
|
Min.
kW
|
Min.
kVA
|
|
1/3
|
1.5
|
1.9
|
1.2
|
1.5
|
|
1/2
|
2.0
|
2.5
|
1.5
|
1.9
|
|
3/4
|
3.0
|
3.8
|
2.0
|
2.5
|
|
1
|
4.0
|
5.0
|
2.5
|
3.125
|
|
1-1/2
|
5.0
|
6.25
|
3.0
|
3.8
|
|
2
|
7.5
|
9.4
|
4.0
|
5.0
|
|
3
|
10.0
|
12.5
|
5.0
|
6.25
|
|
5
|
15.0
|
18.75
|
7.5
|
9.4
|
|
7 1/2
|
20.0
|
25.0
|
10.5
|
12.5
|
|
10
|
30.0
|
37.5
|
15.0
|
18.8
|
NOTES:
To avoid damage to your motor or pump, it is recommended
that the generator be started and permitted to come up to voltage before
the pump or motor is turned on.
- A majority of industrial
generators are externally regulated. Generators must be sized to deliver
at least 65% of the rated voltage during motor starting to ensure adequate
motor starting torque.
- Industrial generators
typically produce 300+ percent of rated capacity for 15-20 seconds during
electrical surges.
- To convert KW into watts
multiply KW (x) 1000
NEMA
CODES FOR STARTING KVA/hp THREE PHASE MOTORS
|
CODE
|
STARTING KVA / HP
|
TYPICAL SIZE RANGE
|
CODE
|
STARTING KVA / HP
|
TYPICAL RANGE
|
|
A
|
0 - 3.15
|
--
|
L
|
9.0 -10.0
|
1 HP
|
|
B
|
3.15 - 3.55
|
--
|
M
|
10.0 - 11.2
|
Less than 1
HP
|
|
C
|
3.55 - 4.0
|
--
|
N
|
11.2 - 12.5
|
--
|
|
D
|
4.0 - 4.5
|
--
|
P
|
12.5 - 14.0
|
--
|
|
E
|
4.5 - 5.0
|
--
|
R
|
14.0 - 16.0
|
--
|
|
F
|
5.0 -5.6
|
15 HP and up
|
S
|
16.0 - 18.0
|
--
|
|
G
|
5.6 - 6.3
|
10 HP
|
T
|
18.0 - 20.0
|
--
|
|
H
|
6.3 - 7.1
|
7.5 and 5 HP
|
U
|
20.0 - 22.4
|
--
|
|
J
|
7.1 - 8.0
|
3 HP
|
V
|
22.4 and up
|
--
|
|
K
|
8.0 - 9.0
|
2 and 1-1/2
|
|
|
|
|
