BLC012-1 Fuji Electric holdings CO.,Ltd, BLC012-1 Datasheet - Page 11

• Manufacturer Part Number: BLC012-1
• Description: Low Voltage Fuses Blc, Cr And Cs Types Super Rapid Fuses
• Manufacturer: Fuji Electric holdings CO.,Ltd

I
BLC, CR and CS-type – Super rapid
fuse
When selecting fuses for
semiconductor rectifier circuit protection
the following conditions must be
satisfied.
For additional details contact FUJI.
I
1. The rated interrupting current of the
2. The let-thru current value of fuse
3. The total clearing I
4. The rated current of the fuse must be
5. The rated current and voltage of the
Method of application
Semiconductor rectifier equipment has
a variety of rectifier circuits. Taking the
3-phase bridge rectifier circuit as an
example – Fig. (a) and (b) as shown in
the following.
Although the number of fuses used in
the line fuse method (a) is half the
number used in the element fuse
method (b), the fuses must have a
larger current capacity.
Fuji Electric FA components & Systems Co., Ltd./D & C Catalog
Information subject to change without notice
fuse must be greater than the
estimated short circuit current of the
circuit.
Available short
circuit current
of rectifier circuit
must be less than the allowable 1/2
cycle surge current value.
Fuse let-thru
current value
fuse requires to complete interruption
must be less than the allowable I
value of semiconductor.
Fuse – total
clearing I
greater than the average forward
current of the semiconductor.
Fuse –
rated current
fuse must be greater than those of
the rectifier circuit.
Fuse – rated
current and
voltage
Application and selection guide
Conditions of application
2
t
< =
< =
>
>
<
Semiconductor – 1/2
cycle allowable surge
current 10ms (at 50Hz)
Semiconductor – I
Semiconductor –
average forward current
Rectifier circuit –
current and voltage
2
t value which the
Rated interrupting
current of fuse
2
t
2
t
Fig. (a)
Line fuse method
In this method the fuses are connected to
the AC line side.
Fig. (b)
Element fuse method
In this method the fuses are connected in
series to the semiconductor element.
Fig. 1 Rated voltage required by fuses
Remarks: The 'a' is a coefficient where the regulation of the AC input voltage is taken into account. This
Fig. 2 Element current and line current
Wire connection
type
Single-phase bridge
3-phase bridge
3-phase, double star
Wire connection
type
Single-phase bridge
3-phase bridge
3-phase, double star
is a=1.1 in case of voltage regulation ±10%.
Wiring diagram
Wiring diagram
E
I
I
E
a
a
I
E
I
a
a
I
I
a
d
I
a
I
d
I
d
I
When selecting fuses various factors
such as protection, coordination and
load, etc. must be considered.
However, in this catalog the main
matters such as voltage, current and I
only are explained.
G
The rated voltage of the fuse indicates
the maximum operational voltage and
this also indicates the root-mean-
square value of the AC sinusoidal wave
voltage. Select fuses having a rated
voltage exceeding the voltage obtained
by the formula shown in the following
table. (Fig. 1)
Do not select current-limiting fuses with
rated voltages drastically exceeding the
rectifier circuit voltage. It is necessary
to consider the arc voltage.
Rated voltage of Fuse (V
For line fuse
V
V
V
Element fuse method
Element current I
Ia =
I = Ia =
Ia =
Rated voltage
FN
FN
FN
Fuse ratings
= 0.577dI
= 0.707d
> =
> =
> =
√
√
BLC, CR and CS types
a · E
a · E
a · 3 · E
Id
_
Id
_
3
= 0.289dI
2
_
_
2
a
a
√
Id
Super Rapid Fuses
_
3
_
Low Voltage Fuses
a
a
I =
For element fuse
V
V
V
Line fuse method
Line current
I = d
FN
FN
FN
FN
= 0.816dI
rms)
> =
> =
> =
a · E
a · E
a · 3 · E
2
3
Id
a
a
08/45
I
a
2
t
08