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Integrator box
Amplifier
Protection relay
Rogowski
coil
I
I>
Figure 251: Rogowski coil measurement arrangement
It is also possible to feed shaft current, measured with CT, directly to the relay
current input. Proper signal levels need to be ensured for reaching acceptable
operation accuracy.
Setting
Alarm start value and Operate start value
The current level that causes damage to bearings depends on the contact surface of
the bearings. Current densities over 0.1 A/mm
2
start to damage the bearings. This
can be generalized so, that currents over 1 A can be considered harmful. Therefore,
the recommended setting for
Operate start value is 0.5 A and for Alarm start value
0.25 A. Both values are set in primary amperes.
4.1.12.7
Signals
GSLPTOC Input signals
Table 496: GSLPTOC Input signals
Name
Type
Default
Description
ISHFT
SIGNAL
-
Analog input
BLOCK
BOOLEAN
0=False
Block signal for all bi-
nary outputs
GSLPTOC Output signals
Table 497: GSLPTOC Output signals
Name
Type
Description
OPERATE
BOOLEAN
Operate
START
BOOLEAN
Start
ALARM
BOOLEAN
Alarm
Protection functions
1MRS759142 F
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REX640
Technical Manual