14
Power supply
and output
relay module
To be able to operate the relay needs a secured
auxiliary voltage supply. The power supply mod-
ule forms the voltages required by the measur-
ing 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 out-
put relays, the control circuits of the output re-
lays and the electronic circuitry of the external
control signals.
The power supply and output relay unit 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withdrawn after removing the system front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 ±12V and +24 V
are stabilized in the power supply module, while
the +5 V logic voltage required by the measur-
ing relay module is formed by the stabilizer 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. 11. Voltage levels of the power supply module.
A green LED indicator Uaux 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 value by more than 25 %,
a selfsupervision alarm will be established. An
alarm is also received when the power supply
module is withdrawn from the relay case, or
when the auxiliary power supply to the relay is
interrupted.
There are two versions of the power supply and
output relay modules available. For both types,
the secondary sides and the relay configurations
are identical, but the input voltage ranges dif-
fer.
Insulation test voltage between the primary and
the secondary side and the protective earth.
2 kV, 50 Hz, 1min
Rated power P
n
5 W
Voltage ranges of the power supply modules:
- SPTU 240 R2 U
aux
= 80 ... 265 V ac/dc
- SPTU 48 R2 U
aux
= 18 ... 80 V dc
(on request)
The module SPTU 240 R2 can be used with
both ac and dc voltages. Module SPTU 48 R2
is designed for dc supply only. The auxiliary
voltage range of the power supply module of
the relay assembly is indicated on the system
front panel.
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