GE AKD-10 Application Manual page 28

Table 27.1 Transformer forced cooled ratings
Self-cooled
Transformer type
Liquid filled: 65° C rise 750-2000
2500-5000
Liquid filled: 55/65° C rise 750-2000
2500-5000
Ventilated dry 750-2500
Cast coil 500-2500
3000-5000
Table 27.2 480 volts, three phase
Transformer
rating 3-phase Max short-circuit
kVA and MVA available continuous
impedance from primary
(amperes) Œ Ž
percent system
50
100
150
4.5% 
500
250
500
750
Unlimited
50
100
150
750
250
5.75%
500
750
Unlimited
50
100
150 Ž (1684)
1000
250
5.75%
500
750
Unlimited
50
100
150
1000
250
8%
500
750
Unlimited
50
100
150
1500
250
5.75%
500
750
Unlimited
50
100
150
2000
250
5.75%
500
750
Unlimited
50
100
150
2500
250
5.75%
500
750
Unlimited
50
100
150
3000
250
5.75%
500
750
Unlimited
50
100
150
3750
250
5.75%
500
750
Unlimited
ΠWith transformer operating on base temperature rise, without fans. Larger frame size main
breaker may be required when dual temperature rise for forced cooled transformers are used.
 Minimum impedance.
Ž Maximum forced cooled rating indicated in parentheses.
L = Long-time delay trip (overload tripping)
S = Short-time delay trip (selective fault tripping)
I = Instantaneous trip (high fault current fast tripping)
kVA % increase with fans
15%
25%
15% (fans) + 12% (65° C)
25% (fans) + 12% (65° C)
33%
40%
25%
Short-circuit rating sym current (A)
Full load
current Transformer 100%
alone Motor load
10900
12000
12400
601 12800 2400
13100
13200
13400
12400
13900
Ž (1263) 902 14400
14900 3600
15300
15400
15700
15500
17800
1203 18700
19600 4800
20200
20400
20900
12000
13400
Ž (1684) 1203 13900
14300 4800
14700
14800
15000
20600
24900
Ž (2526) 1804 26700
28400 7200
29800
30300
31400
24700
31000
Ž (3368) 2406 34000
36700 9600
39100
40000
41800
28000
36400
Ž (4210) 3007 40500
44500 12000
48100
49400
52300
30700
41200
Ž (5052) 3608 46600
51900 14400
56800
58700
62800
34000
47500
54700
4511 62200 18000
Ž (6315) 69400
72200
78400
Main
Fully rated or
selective Selective
Fully rated
arrangement
LI
LS
Selectively
coordinated
arrangements
Distribution or motor control center
Long-time inst.
or long-time Long-time
Combined short-time ¿ short-time
13300
14400
14800
15200 WPS-08
15500
15600
15800
16000
17500
18000
18500 WPS-16 WPS-08
18900
19000
19300
20300
22600
23500
24400 WPS-16 WPS-08
25000
25200
25700
16800
18200
18700
19100 WPS-16 WPS-08
19500
19600
19800
27800 WPS-08
32100
33900
35600 WPS-20 WPH-08
37000
37500
38600
34300
WPH-08
40600
43600
46300 WPS-32
48700 WPX-08
49600
51400
40000 WPH-08
48400
52500
56500 WPS-32
WPX-08
60100
61400
64300
45100
WPX-08
55600
61000
66300 WPS-40
71200 WPH-32
73100
77200
52000 WPX-08
65500
72700
WPH-32
80200 WPS-50
87400
90200 WPX-32
96400
Feeder circuit breakers
Zone
selective Fully rated
LS LSI LI
Long-time
short-time Long-time
inst. inst.
WPS-08 WPS-08 WPS-08
WPS-08 WPS-08
WPS-08 WPS-08
WPS-08 WPS-08
WPS-08 WPS-08
WPH-08 WPH-08
WPH-08 WPH-08
WPX-08 WPX-08
WPH-08 WPH-08
WPX-08 WPX-08
WPX-08 WPX-08
WPH-32 WPH-32
WPX-08 WPX-08
WPH-32 WPH-32
WPX-32 WPX-32
LI
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