WEG SSW-08 User Manual - page 20
3
Installation and Connection
SSW-08 | 15
3.2.4.1 Power Supply Capacity
The Soft-Starter SSW-08 is suitable to be used in a circuit capable of supplying not more than
X (according to table 3.6) symmetrical rms amperes, Y maximum volts when protected by ultra-
rapid fuses.
Table 3.6: Maximum current capacity of the Power supply
SSW-08
Model
Y = 220-575 V
X (kA)
17 A
5
24 A
5
30 A
5
45 A
5
61 A
5
85 A
10
130 A
10
171 A
10
200 A
10
255 A
25
312 A
25
365 A
25
412 A
25
The SSW-08 can be installed on power supplies with a higher fault level, if it is protected by
ultra-rapid fuses with an adequate interrupting current and an I
2
t according to item 3.2.4.2.
3.2.4.2 Recommended Fuses
High speed fuses must be used at the input, wich will protect the SSW-08 against short circuit.
It is possible to use other protection devices that will protect the installation; however, in that
case the SSW-08 will remain unprotected.
The fuse rated current should preferably be equal or greater the motor starting current to avoid
cyclic overloads and fuse opening in the forbidden region of the Time x Current curve.
Table 3.7: Recommended fuses
SSW-08
Model
Nominal
Current
(A)
Maximum
I
2
t
(10
3
x A
2
s)
UL Fuses
WEG
Fuses
Control
Fuses
Ferraz Shawmunt/
Mersen
Cooper
Bussmann
17 A
50
0.72
6.6URD30TTF0050
170M2611
10806688
2 A
(D Type)
or
2 A
Circuit
Breakers
(C Type)
24 A
80
4
6.6URD30TTF0080
170M1366
10705995
30 A
80
4
6.6URD30TTF0080
170M1366
10707110
45 A
100
8
6.6URD30TTF0100
170M1367
10701724
61 A
125
10.5
6.6URD30TTF0125
170M1368
10809489
85 A
200
51.2
6.6URD30TTF0200
170M1370
10711445
130 A
315
97
6.6URD31TTF0325
170M1372
10824053
171 A
450
168
6.6URD32TTF0450
170M3170
10824109
200 A
500
245
6.6URD33TTF0500
170M3171
10824110
255 A
500
90
6.6URD33TTF0500
170M3171
10833056
312 A
630
238
6.6URD33TTF0630
170M3173
10833591
365 A
630
238
6.6URD33TTF0630
170M3173
-
412 A
700
320
6.6URD33TTF0700
170M6161
-
NOTE!
The maximum I
2
t of the SSW-08 255A fuse is smaller than 200A because of the
thyristor constructive type used on this soft-starter.