Fuses and fuse systems, Introduction – Siemens AC-21A User Manual
Page 29
Siemens LV 10 · 2004
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Fuses and Fuse Systems
Introduction
7
■
Benefits
For the 3KL switch disconnectors with fuse, a UL approval has
been granted in combination with the new 3NE1 ...–2 fuse
series.
■
Area of application
When SITOR semiconductor protection fuses are used in
SENTRIC NP, SENTRIC KL and 3KM switch disconnectors, a
partial reduction of the rated current of the fuse is necessary due
to the higher power loss in comparison with LV HRC fuses for line
protection. The use of SITOR semiconductor protection fuses in
switch disconnectors may at times result in current values above
the rated currents of the switches. These increased currents oc-
cur only when the switch is used with SITOR semiconductor pro-
tection fuses; they cannot be utilized when the switch is used
with standard LV HRC fuses. Details are given in the table below.
When SITOR semiconductor protection fuses of series 3NC24,
3NC84, 3NE33 and 3NE43 are used, the switching capacity of
the switch disconnectors as specified in the catalog must not be
fully utilized, as the blades of these fuses (in contrast to LV HRC
line-protection fuses) are slotted. Occasional switching of cur-
rents up to the rated currents of the fuses is permissible.
Due to the mechanical stress on the relatively long fuse blades,
3NE41 SITOR semiconductor protection fuses should be
switched only occasionally and only at zero current. If it is only
permissible to switch at zero current, the switch must be marked
accordingly.
The use of SITOR semiconductor protection fuses rated above
63 A for overload protection is also not permitted when gR fuses
(except 3NE1) are used.
The operating voltage is limited by the rated voltage of the
switch disconnector or the fuses. During current-free switching,
the limit value is the rated insulation voltage of the switch discon-
nector.
The 3NE1 “double protection fuses” can be used both as all-
range fuses (gR/gS) as well as for semiconductor and line pro-
tection.
Due to the dimensions of SITOR semiconductor protection
fuses, only the fuses shown in the Selection and ordering data
below can be used in the SENTRIC NP, SENTRIC KL and 3KM
switch disconnectors.
■
Selection and ordering data
1) If a cyclic load is applied, it may be necessary to further reduce the cur-
rents (please inquire about precise values).
2) Values in brackets apply to the SENTRIC 3NP4 fuse switch disconnector.
For switch disconnectors
SITOR semiconductor protection fuse
Type
Type
Permissible load cur-
rent of the SITOR
semiconductor protec-
tion fuse in the switch
disconnector
1)
Required conductor
cross-section
Cu
Size
Opera-
tional
class
Rated
current
Rated
voltage
DT
Order No.
PS*
Weight
per PU
approx.
A
mm
2
A
V
kg
For SENTRIC 3NP fuse switch disconnectors
3NP35,
3NP40 1,
16
1.5
000
gR/gS
16
690
}
3NE1 813-0
9 units
0.127
3NP50
3NP40 7
20
2.5
gR/gS
20
}
3NE1 814-0
9 units
0.128
25
4
gR/gS
25
}
3NE1 815-0
9 units
0.127
35
6
gR/gS
35
}
3NE1 803-0
9 units
0.128
40
10
gR/gS
40
690
}
3NE1 802-0
9 units
0.127
50
10
gR/gS
50
}
3NE1 817-0
9 units
0.128
63
16
gR/gS
63
}
3NE1 818-0
9 units
0.128
80
25
gR/gS
80
}
3NE1 820-0
9 units
0.129
3NP50
3NP40 7
100
35
00
gR/gS
100
690
}
3NE1 021-0
3 units
0.202
125
50
gR/gS
125
}
3NE1 022-0
3 units
0.202
125 (105)
2)
50
gR
125
}
3NE1 022-2
3 units
0.203
3NP52
3NP42 7
160
70
1
gR/gS
160
690
}
3NE1 224-0
3 units
0.580
160
70
gR
160
}
3NE1 224-2
3 units
0.613
200
95
gR/gS
200
}
3NE1 225-0
3 units
0.582
200 (190)
2)
95
gR
200
}
3NE1 225-2
3 units
0.612
250
120
gR/gS
250
}
3NE1 227-0
3 units
0.580
250 (235)
2)
120
gR
250
}
3NE1 227-2
3 units
0.626
3NP53
3NP43 7
315
2 × 70
2
gR/gS
315
}
3NE1 230-0
3 units
0.581
315
2 × 70
gR
315
}
3NE1 230-2
3 units
0.615
3NP53
3NP43 7
350
2 × 95
2
gR/gS
350
690
}
3NE1 331-0
3 units
0.766
350
2 × 95
2
gR
350
}
3NE1 331-2
3 units
0.754
400
2 × 95
gR/gS
400
}
3NE1 332-0
3 units
0.743
3NP54
3NP44 7,
450
2 × 120
gR/gS
450
}
3NE1 333-0
3 units
0.760
3NP44 76
450 (425)
2)
2 × 120
gR
450
}
3NE1 333-2
3 units
0.768
500 (480)
2)
2 × 120
gR/gS
500
}
3NE1 334-0
3 units
0.766
500 (465)
2)
2 × 120
gR
500
}
3NE1 334-2
3 units
0.768
* This quantity or a multiple thereof can be ordered.