Atlas Copco XAHS 37 DD Instruction Manual page 23

Instruction Manual
Operation of the electric circuit in detail
Start switch S1 position 1:
Line 2 on 12V contact K3 closed (13-11), lamp H2 is on. K4
excites contact K4 (18-15). Thermocontact element S5 normally
closed, K1 excites contact K1 (1-4).
Use of lamp test:
Start switch S1 position 1 press lamp test S4, across K3 and line
9 lamp H1 and relay K2 are excited. After releasing lamp test
button S4, lamp H1 remains on, S4 taken over by contact K2.
Start switch S1 position 2:
Line 3 on 12V (overwrite function) hourmeter P1 and fuel
solenoid Y1 excited. Thermocontact engine S2 normally closed,
oil pressure contact S3 open.
Start switch S1 position 3:
Start relay K0 is excited and starter motor is running, engine
builds up oil pressure and oil pressure contact S3 closes. K3
excited and contact K3 changes over to (13-10). Relay K2 no
longer excited, contact K2 opens, lamp H1 goes out. Alternator
also commences supplying voltage and K4 is no longer excited
and contact K4 changes over to (18-16). Lamp H2 goes out, one
can release start switch S1 and it returns to position 1. Exciting
the safety devices occurs no longer across line 3 but across line 2
to line 4 and this way to line 3.
Engine is running normally:
Oil pressure contact S3 opens, K3 no longer excited.
K3 changes over (13-11), engine cuts out because fuel solenoid
Y1 no longer excited and lamp H2 goes on simultaneously.
Thermocontact S2 opens, K3 no longer excited.
K3 changes over (13-11), engine cuts out because fuel solenoid
Y1 no longer excited and lamp H2 goes on simultaneously.
Thermocontact S5 opens, K1 no longer excited. Contact K1
changes over (4-2). K3 no longer excited. K3 changes over (13-
11), engine cuts out because fuel solenoid Y1 no longer excited
and lamp H2 and H1 go on simultaneously. Take-over relay K2
is excited simultaneously with H1 and contact K2 closes (8-6).
Thermocontact S5 cools off and closes, K1 excited again and
contact K1 changes over (4-1). However, lamp H1 remains on
across line 9 and contact K2 (6-8).
A fault in the alternator part causes terminal D+ to go to 0V and
K4 to be excited. Contact K4 changes over to (18-15), engine
cuts out because fuel solenoid Y1 no longer excited and lamp H2
goes on simultaneously.
Generator function:
Turn switch S7 to position 1. The solenoid valve Y2 via the speed
regulator SR controls the motor and allows it to reach maximum
speed (the normal control system is switched off). Lamp H3 is
activated. Time relay K7 disconnects the sockets from the
generator during 4 sec, after which the sockets X1, X2, X3 are
under tension.
The generator can be switched off by turning switch S7 to
position 0.
If switch S7 is turned on, lamp H4 and ecologiser E1 are
activated. E1 senses continuously the current to the sockets. If no
current is sensed, time relay K8 is activated. This time relay
deactivates the solenoid valve Y2 so that the speed regulator is
again controlled by the normal compressor control system. When
in this condition E1 senses current to the sockets, the solenoid
valve Y2 is re-activated immediately by K8. Time relay K7
disconnects the sockets from the generator during 4 sec, after
which the sockets X1, X2, X3 are under tension.
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