21. Internal Fuse
The thyristor unit have internal fuse extrarapid at low I²t for the thyristor protection of against the short-circuits.
The Fuses must have I²t 20% less than thyristor’s I²t. The warranty of thyristor is null if no proper fuses are used.
Type
Fuse Code Spa-
re Part
Current (ARMS)
Vac
FUSE I2T value
Suggested A2s
(at500V)*
FUSE I2T value
Suggested A2s
(at660V)
060
20 559 20.160
160
660
10780
15400
090
20 559 20.160
160
660
10780
15400
120
20 559 20.180
180
660
14280
20400
150
20 559 20.200
200
660
17500
25000
180
20 559 20.250
250
660
30800
44000
210
20 559 20.315
315
660
53900
77000
Caution: High speed fuses are used only for the thyristor protection and can not be used to
protect the installation.
Caution: The warranty of thyristor is null if no proper fuses are used. See tab.
Warning: When it is supply, the Thyristor unit is subject to dangerous voltage, don’t open the
Fuse-holder module and don’t touch the electric equipments.
1.2
1.0
0.8
0.6
0.4
0.2
200 400 600 800
0.7
500
Vca
K
(Line Voltage)
*I2T are multiplied for K value in function of Vac at 500V K is
equal to 0,7 (ex:15400 X 0,7 = 10780).
At 660Vsc K is equal to 1.
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