Pump Rental Booklet - Catalog - Page 133
Generator Sizing
Common methods of starting AC motors mean that if they are to be supplied
from a Generator supply, then this has to be sized to accommodate the high
starting currents. A typical example of this is as follows:
55kW motor, 400 volts, 3 phase, 50 Hz with a full load current of 113 Amps
using VSD control panel would be 89Kva. This would then be rounded up to
the next size generator, ie. 100KVA. This figure is reached using the following
calculation:Full load current (including starting current)
1.4
This would give the perfect KVA which would have to be divided by 0.9, the
factor for an older generator.
Power
Rating
(kW)
2.0
3.1
4.2
5.2
7.4
8
13.5
22
30
37
45
55
125
Full Load
Current
(amps)
4.8
6.8
8.2
12
14
18
28
43
54
77
93
113
234
VSD
DOL
Soft Start
Generator Generator Generator
(KVA)
(KVA)
(KVA)
7.5
20
7.5
30
10
45
15
50
15
75
20
75
30
100
75
45
100
75
125
75
200
100
225
100
250
200
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Motor Starter Types
Direct Online
Star / Delta
Soft Start
Variable Speed Drive
Typical Starting Current
5 x Full Load Current
4 x Full Load Current
3 x Full Load Current
1 x Full Load Current
Typicle Motor
Full Load Current
415 VOLT
kW
(amps)
2.0
4.8
2.2
4.5
2.4
4.7
3.1
6.8
4.2
8.2
5.2
12.0
8.0
18.0
10.0
19.0
13.5
28.0
15.0
28.0
18.0
32.0
20.0
35.0
22.0
43.0
30.0
54.0
37.0
77.0
45.0
93.0
55.0
113.0
125.0
234.0
