9
To be able to operate the relay needs a secured
auxiliary voltage supply. The power supply
module forms the voltages required by the meas-
uring relay module and the auxiliary relays. The
withdrawable power supply and output relay
module is located behind the system front panel,
which is fixed by means of four cross-slotted
screws. The power supply and output relay
module contains the power supply unit, all
output relays, the control circuits of the output
relays and the electronic circuitry of the external
control inputs.
The power supply and output relay module can
be withdrawn after removing the system front
panel. The primary side of the power supply
module is protected with a fuse, F1, located on
the PCB of the module. The fuse size is 1 A
(slow).
The power supply unit is a transformer con-
nected, i.e. galvanically isolated primary and
secondary side, flyback-type dc/dc converter. It
forms the dc secondary voltages required by the
measuring relay module; that is +24 V,
±
12 V
and +8 V. The output voltages
±
12 V and +24
V are stabilized in the power supply module,
while the +5 V logic voltage required by the
measuring relay module is formed by the stabi-
lizer of the relay module.
1 A slow
+8V
+12V
-12V
+24V
Uaux
80...265 V ac & dc
18...80 V dc
Unstabilized logics
voltage
Operation amplifier
voltage
Output relay coil
voltage
Fig. 5.Voltage levels of the power supply module.
A green LED indicator U
aux
on the system front
panel is illuminated when the power supply
module is in operation. The supervision of the
voltages supplying the electronics is placed in
the measuring module. If a secondary voltage
deviates from its rated too much, a self-supervi-
sion alarm will be established. An alarm is also
established when the power supply module is
withdrawn from the relay case, or when the
auxiliary power supply to the relay is inter-
rupted.
There are two versions of power supply and
output relay modules available. For both types,
the secondary sides and the relay configur-
ations are identical, but the input voltage ranges
differ.
Voltage ranges of the power supply modules:
- SPTU 240R2 or
SPTU 240R3
U
aux
= 80...265 V dc/ac
- SPTU 48R2 or
SPTU 48R3
U
aux
= 18...80 V dc
The modules SPTU 240 R2 or SPTU 240 R3
can be used with both ac and dc voltages.
Modules SPTU 48 R2 and SPTU 48 R3 are
designed for dc supply only. The auxiliary volt-
age range of the power supply module of the
relay assembly is indicated on the system front
panel.
The module SPTU 240R2 and SPTU 48R2
have a normally open trip contact whereas the
modules SPTU 240R3 and SPTU 48R3 have a
normally closed trip contact.
Power supply
and output relay
module
