ABB GFD212A inverter control cabinet logic board
Fig. 4. Signal diagram of the combined overcurrent and earth-fault relay type SPAJ 140 C
The functions of the blocking and start signals
are selected with the switches of switchgroups
SGF, SGB and SGR. The checksums of the
switchgroups, are found in the setting menu of
the protection relay module. The functions of
the different switches are explained in detail in
the user´s manual of the protection relay mod ule SPCJ 4D29.
Signal diagram The figure below schematically illustrates how
the start, trip, control and blocking signals can
IL1, IL2, IL3 Energizing current of phase L1, L2 and L3
I0 Neutral current (Residual current)
BS Blocking or control signal
SS1 Start signal 1
SS2 Start signal 2
SS3 Start signal 3
TS1 Operate signal 1 (Trip signal 1)
TS2 Operate signal 2 (Trip signal 2)
BS Blocking signal
AR1...3 Auto-reclose start signals (not in use in relay SPAJ 140 C)
IRF Internal relay failure
SGF Switchgroup for functions
SGB Switchgroup for blockings
SGR Switchgroup for relay configuration

The indicator TRIP is lit when one of the
protection stages operates. When the protec tion stage resets, the red indicator remains lit.
B) If the display is dark when one of the protec tion stages I>, I>>, I0> or I0>> operates, the
faulty phase or the neutral circuit is indicated
with a yellow LED. If, for instance, the TRIP
indicator glows red, and the indicators IL1
and IL2 at the same time are lit, overcurrent
has occurred on phase L1 and L2.
C) Besides being a code number at data presen tation, the leftmost red digit in the display
serves as a visual operation indicator. An
operation indicator is recognized by the fact
that the red digit alone is switched on. The
following table named OPERATION IND.
on the relay front panel is a key to the
function code numbers used.