Atlas Copco XAHS 37 DD Instruction Manual page 19

Instruction Manual
Fig. 2.5 Location of relais K1-K4
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.
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