9
To be able to operate the relay needs a constant
supply of auxiliary energy. The power supply
module forms the voltages required by the
protection relay modules and the auxiliary relay
module. The module is located behind the
system front plate together with the output
relay module. The power supply module can
be withdrawn after removing the system front
plate .
The power supply module is a transformer
connected, i.e. galvanically isolated primary
and secondary side, flyback-type dc/dc
Power supply
module
converter. The primary side of the power supply
module is protected with a fuse, F1, located on
the PC-board of the module. The fuse size is
1 A (slow).
The power supply module forms the secondary
voltages required by the relay modules; i.e.
+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 relay modules is formed from
the +8 V by the stabilizers of the concerned
relay modules.
Fig. 6. Voltage levels of the power supply 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
A green LED indicator marked U
aux
on the
system front plate is illuminated when the
power supply module is in operation. The
supervision of the voltages supplying the
electronics is placed in the relay modules.
Should the secondary voltage deviate from its
rated value by more than 25 %, a self-
supervision alarm will follow. An alarm is also
received when the power supply module has
been removed from the relay case or when the
auxiliary power supply to the relay has been
interrupted.
There are two versions of power supply
modules available. The secondary sides of
both types have identical ratings, but the input
voltage ranges vary.
Insulation test voltage between primary and
secondary side and the protective earth
2 kV, 50 Hz, 1 min.
Rated power P
n
=15 W
Input voltage ranges of the auxiliary power
modules
- type SPGU 240A1
U
aux
= 80…265 V dc or ac
- type SPGU 48B2
U
aux
= 18…80 V dc
B