Siemens E382 EH81E 061 01 03 02 Service Manual page 17

Compressor Compact
3.9 Pressure regulator
The compressed air supply is tapped off at a
three-port coupling at the thermoelectric
cooler-inlet and applied to the PRESSURE
REGULATOR. This device is actually a relief
valve.
Pressure in excess of the set level, normally
approx. 400 kPa (4.0 bar), opens this relief
valve. The excess compressed air flow is
returned to the inlet of the 1.6 COMPRES-
SOR via the 1.2 SILENCER. This arrange-
ment effectively silences the outlet of this
relief valve.
For pressure adjustment, see the chapter
Adjustments.
The pressure regulator must be overhauled
at the 8000 hour overhaul.
3.10 Electric power supply
The ELECTRIC POWER SUPPLY is a
collective name for some of the parts
included in the power supply to the different
electrical components in the compressor.
Mains power (115 or 230 V AC) is connected
to the on/off switch (via the mains power
fuses) and from here distributed to the:
• Operating time meter
• Fan
• Compressor motor
• Transformer.
All other electrical components are supplied
with 12 V DC.
The main parts in the ELECTRIC POWER
SUPPLY block are the:
• Transformer
• Rectifier with capacitor
• Start relay (compressors with standby
function).
E382 EH81E 061 01 03 02
The transformer used in the compressor is a
toroid transformer. There are two different
versions of the transformer, one for 115 V
mains power supply and one for 230 V
mains power supply. The output is 12 V and
max power consumption is 100 VA for both
transformers.
Transformers with serial number extention
-0017 are fitted with a self-resetting thermal
switch that will disconnect the current through
the transformer if it is overheated. When the
transformer cools down, the thermal switch
will automatically reconnect the current
through the transformer.
As transformers fitted with termal switch
can reconnect automatically, all personnel
must exercise extreme caution when in
the vicinity of this equipment if fault tracing
is performed with mains power supply
connected and with the compressor cover
opened or removed.
The compressor is equipped with a rectifier
that is supplied with 12 V AC from the
transformer. The rectifier consists of a
rectifier bridge assembled as a complete,
exchangable unit.
The rectifer smoothing capacitor used is
rated 24 V, 22 000 µF.
3.11 Electrical interconnection
The different electrical components are
connected to the ELECTRICAL INTER-
CONNECTION terminal. The three fuses
mentioned in the description of 3.12 FUSES
are located in this terminal block.
Siemens-Elema AB
Description of functions
17