Murphy MC-900 Series - Manual (Page 10)

8
been adjusted for proper running speed, turn Mode
Selector switch OFF.
(e) All lights on the back of the MC-900 should go off and
the engine stop. If engine does not stop, check run
solenoid to be sure it has returned to the stop position.
4-4.3 Overspeed Switch Setting; To set the speed switch,
proceed as follows:
(a) Turn Mode Selector switch to the START position.
(b) Engine should crank and start. Return switch to RUN
position.
(c) With engine running, adjust governor to bring engine
speed to normal RPM.
(d) Depress and hold the Overspeed Test pushbutton.
(e) Slowly turn the Overspeed Set adjustment counter-
clockwise until the “Overspeed” and “Overspeed Relay”
lights on the MC-900 come on and the engine shuts
down.
(f) Release pushbutton; check “Overspeed” light on front
panel to be sure it is on.
(g) Turn Mode Selector switch OFF to reset shutdown
circuits.
(h) Restart engine, when engine starts, increase governor
speed setting slowly until engine shuts down on
overspeed. This should occur about 10% above
governor speed.
(i) Turn Mode Selector switch OFF.
4-4.4 Overcrank setting; to test the time before system shuts
down on overcrank;
(a) Disconnect the run solenoid wire from terminal 6 of the
Relay Module.
(b) Check time set on the “Crank Time” switch on MC-900
back panel. It is factory set at 15.
(c) Turn Mode Selector switch to START.
1. Engine will crank for 15 seconds.
2. After 15 seconds the “Overcrank” light on the MC-
900 will come on and engine will stop cranking.
(d) Turn Mode Selector switch OFF.
(e) Reconnect the run solenoid wire at terminal 6 of the
Relay Module.
4-4.5 Oil Pressure; to test oil pressure shutdown circuit:
(a) Turn Mode Selector switch to START. When engine
starts, wait 30 seconds then,
(b) Use a jumper wire and short from terminal 28 to 4.
(c) ”Oil Pressure” light will come on and engine will stop.
(d) Turn Mode Selector switch OFF.
4-4.6 Water Temperature; to test the water temperature
shutdown circuit:
(a) Turn Mode Selector switch to START. When engine
starts, wait 30 seconds then,
(b) Use a jumper wire and short from terminal 29 to 4.
(c) “Water Temperature” light will come on and engine will
stop.
(d) Turn Mode Selector switch OFF.
4-4.7 All other Shutdowns; all other shutdowns would be
tested in the same manner.
(a) For shutdown circuits which are locked out by the
Shutdown Time Delay Bypass, you must wait 30
seconds before running the test.
(b) Circuits that are not locked out may be tested as soon as
the engine is running or may be tested without starting
the engine by turning the Mode Selector switch to RUN
position.
(c) To test other shutdowns, a jumper wire can be used to short
the input terminal for that circuit, to ground, terminal 4.
Section 5: Operation
5-1 Operator Controls.
5-1.1 Mode Selector Switch; allows the operator to start the
engine (START), run the engine (RUN), or stop the engine
(OFF).
5-1.2 The OFF position on the mode selector also provides a
reset function for the shutdown circuits. If the engine is shut
down by the automatic control, the operator must turn selector
off and back on to reactivate the system.
5-1.3 Push to Test Lamps; this pushbutton tests the shutdown
indicator lights.
5-2 Operating Modes.
5-2.1 The MC-900 Generator Engine Control has only one
operating mode: manual start and automatic shutdown on a
sensed failure of one of the monitored inputs.
5-2.2 Manual electric start is provided for operation of the
generator set.
5-2.2.1 To initiate Manual start, place the Mode Selector
switch in the START position. This provides a start signal to
the engine starter.
5-2.2.2 When engine starts, return selector switch to RUN.
This removes start signal and the engine will run.
5-2.3 OFF or Not Operating; to prevent operation of the
engine, turn selector switch OFF.
5-2.3.1 The OFF position is used as a reset for any automatic
shutdown that occurs.
Section 6: Routine Maintenance
and Operational Tests
6-1 Routine Maintenance.
6-1.1 Due to the design and types of components used, very
little maintenance is required to the MC-900 Control.
6-1.2 Visual inspection of the internal wiring of the control
panel, along with checking wire connections for tightness,
should be done on a semiannual schedule for stand- by systems
or quarterly for prime power. Check wire bundles for chafing
and wear to the insulation of the wires where they contact the
panel or engine.
6-1.4 Shutdown Circuits should be tested on a monthly basis
for prime power and quarterly for stand-by sets. The same
tests run during pre-operation check out, Section 4-4, should
be included.
6-2 Operational Tests.
6-2.1 No special operational tests are required. The routine
operational tests for the generator set will exercise the control.
Section 7: Troubleshooting and Repair
7-1 Tools Required.
7-1.1 Some of the tools necessary for troubleshooting are built
into the MC-900 Series controls.
7-1.1.1 By observing the lights on the front and rear of the
control panel, clues to a problem and the possible source can
be seen.
DISCONTINUED