ABB REG316 4 Series Operating Instructions Manual page 136

ABB Switzerland Ltd
E. Setting instructions
Settings:
Base current
Characteristic enabling current
Type of characteristic
Multiplier
Characteristic angle
Delay
Time allowed for receipt of signal
Response at the end of the
memorised power direction time
Time during which the memorised
direction is valid
Base current "IB-Setting"
A tripping current is not set on an IDMT overcurrent function as it
is on a definite time overcurrent function. Instead the position of
the characteristic is chosen such that it is above the load current.
The function, however, has a "base current" setting which is set
to the full load current I
setting determines the position of the basic characteristic. The
characteristic is enabled when the base current is exceeded by a
preset amount (I-Start). The adjustment of the base current IB to
the load current I
B1
current enables for
I < rated current of prot. unit : more sensitive protection
B1
I > rated current of prot. unit : maximum utilisation of the
B1
Example:
Load current of the protected unit
C.t rated current
Protection rated current
Protection base current
I
N 2
= =
IB I 800
B 1
I
N 1
Setting
IB 4 A
= =
0 8 . A
I 5 A
N
3-98
REG 316*4 1MRB520049-Uen / Rev. F
of the protected unit. The base current
B1
of the protected unit instead of its rated
thermal capability of the
protected unit.
5 A
=
A 4 A
1000 A
IB-Setting
I-Start
c-Setting
k1-Setting
Angle
Delay
tWait
MemDirMode
MemDuration
I = 800 A
B1
I = 1000 A
N1
I = 5 A
N2
I = 5 A
N