ABB REG316 4 Series Operating Instructions Manual page 221

REG 316*4 1MRB520049-Uen / Rev. F
E. Setting instructions
Settings:
Reference current
Enabling current
Multiplier
Minimum operating time
Time inverse characteristic effective
Maximum delay
Resetting time
The stator overload function protects stator windings against ex-
cessive temperature rise as a result of overcurrents. The func-
tion is applicable to turbo-alternators designed according to the
American standard ASA-C50.13 or a similar standard defining
overload capability.
Providing compensation using the reference value of the A/D
channel has not been made, the reference current IB for the
protection is calculated from the generator load current I
which is usually the same as the generator rated current, and the
c.t. rated currents I
N1
I
N2
=
IB I
B 1
I
N 1
The setting is the ratio IB/I
protection, otherwise "IB-Setting" would be 1.0 IN.
The multiplier k1 is 41.4 s for units designed according to ASA.
For units with a similar overload capacity:
D J - D J
m n
= t
k
1
D J
n
where:
t
: thermal time constant of the stator
DJ
: maximum permissible temperature rise of the stator
m
winding
DJ
: rated temperature rise of the stator winding.
n
IB-Setting
I-Start
k1-Setting
t-min
tg
t-max
t-Reset
and I as follows:
N2
, where I is the rated current of the
N N
[s; s; K]
ABB Switzerland Ltd
,
B1
3-183