Murphy Portable Generator MC 900 Series User Manual

MC-9142N  
Revised 12-00  
Section 40  
(00-02-0202)  
®
SERIES MC-900 MURPHYMATIC  
MANUAL GENERATOR  
ENGINE CONTROL SYSTEM  
DESIGN, INSTALLATION  
AND OPERATING MANUAL  
 
Section 1: Introduction  
1-1 System.  
Section 2: Specifications  
2-1 Enclosure Type.  
®
1-1.1 The MURPHYMATIC Manual Generator Engine 2-1.1 The MC-900 Series enclosure is designed to be mounted  
Control System, Series MC-900 is designed to meet the in a standard electrical enclosure for indoor use.  
requirements of the engine control and shutdown for manual 2-1.2 The MC-900 Series shares the same enclosure as the A-  
start generator engines. 900 automatic start controller so they can be used  
By combining one of the MC-900 series controls with generator interchangeably in a generator control panel.  
instruments, a complete engine generator control panel can be  
2-2 Power Requirements.  
provided.  
2-2.1 The engine controls, shutdown circuits and shut-down  
indicators are powered from the engine starting battery. The  
1-2.1 The Series MC-900 is available in two basic MC-900 series is available in either 12 or 24 volt, negative  
configurations: ground.  
1-2 Models.  
1-2.1.1 Model MC-900 for manual start and stop generator sets 2-2.2 The MC-900 is fused for 3 amp. maximum current.  
with four cycle engines which includes the minimum normal  
2-3 Input Ratings.  
2-3.1 All input switches should be dry contact type, maximum  
current is 2 ma, 8 VDC or less.  
2-3.2 Frequency signal for the speed sensing circuit requires a  
minimum input of 2 volts RMS from a magnetic pickup  
(preferred) or from the tachometer terminal of the battery  
charging alternator.  
2-3.2.1 Frequency range of the speed sensing circuit is 300 Hz  
to 10,000 Hz.  
shutdowns.  
1-2.1.2 Model MC-900-2 for manual start and stop generator  
sets with two cycle engines which includes the minimum normal  
shutdowns and an “Overspeed Relay” to operate the air shutoff  
solenoid for overspeed shutdown.  
1-2.2 Both models are available for 12 or 24 volt operation.  
1-2.3 Both models include four unlabeled shutdown circuits for  
additional customer specified shutdowns.  
1-2.4 Each model is made up of two parts, a Control/Display  
module and a Relay module.  
2-4 Output Ratings.  
2-4.1 The MC-900 Control / Display Module has outputs for  
remote indication of shutdowns. These outputs are transistors  
that close to the negative supply (sink) and are rated at 1 amp,  
30 VDC maximum.  
2-4.2 The Control / Display Module also has an output for an  
auxiliary starter contactor which is rated 1 amp, 30 VDC  
maximum. This is a transistor that closes to the positive supply  
1-3 Purpose.  
1-3.1 This manual is directed to the installation, maintenance  
and operating personnel who will be in day to day contact with  
the MC-900 system.  
1-3.2 No manual can cover all aspects of a product. However  
the basic knowledge gained with this material will allow those  
personnel to easily adjust to special circumstances.  
(source).  
1-4 Definitions. 2-4.3 The Relay Module includes 3 engine control relays with  
1-4.1 Throughout this manual, reference is made to contact ratings of 7 amp, 30 VDC inductive. These powered  
organizations, trade names and trademarks which may not be contacts must be suppied from an 8 amp. fuse or circuit breaker  
(customer supplied).  
familiar to the reader. Some of these are:  
1-4.1.1 NFPA: National Fire Protection Association.  
1-4.1.2 NFPA-70: The National Electrical Code.  
1-4.1.3 Several terms used in this manual are registered  
trademarks of Frank W. Murphy Mfr.  
2-5 Field Wiring Connections.  
2-5.1 All field wiring connections are barrier terminal blocks,  
UL rated for 15 amp, 300 volt.  
2-6 Operating Temperature.  
2-6.1 The operating temperature range of the MC-900 is -4°F to  
158°F / -20°C to 70°C.  
(a) MURPHYMATIC®: Refers to all Murphy automatic  
controls.  
(b) SELECTRONIC®: A name that is applied to all electronic  
controls manufactured by Murphy.  
Section 3: Model Identification  
3-1 Model Numbers.  
(c) SWICHGAGE®: A combination indicating gauge and  
switch.  
3-1.1 MC-900-12 and MC-900-24: These models are designed  
for a manual start four cycle engine driven generator, and  
include the minimum shutdown points normally supplied on  
such installations. The suffix numbers -12 and -24 indicate the  
engine starting battery voltage.  
3-1.2 MC-900-2-12 and MC-900-2-24: These models are  
designed for a manual start two cycle engine driven generator,  
and include the minimum shutdown points normally supplied on  
such installations. The suffix numbers -12 and -24 indicate the  
engine starting battery voltage.  
(d) TATTLETALE®: A term that refers to a shutdown  
indicating device or circuit in the control panel.  
1-5 How to use this manual.  
1-5.1 Section 1, 2, 4, 5, 6 and 7 contain general information that  
applies to all MC-900 models.  
1-5.2 Section 3, Model Identification, is broken into three sub  
sections. Section 3-1 allows you to chose the model that best  
fits your requirements and Section 3-2 and 3-3 explain each  
models features in detail.  
3-1.2.1 The MC-900-2 series control includes an “Overspeed  
Relay” to trip the air shut-off solenoid on overspeed of a two  
cycle engine.  
1
 
3-2 MC-900.  
position. This same delay can also lock out all other  
shutdown circuits except Overspeed and Overcrank.  
The user may select which circuits are locked out by the  
time delay bypass.  
3-2.1 Control / Display Module. The Control / Display  
Module, figure 3-2.1, includes the control and test switches,  
the solid state logic elements and shutdown TATTLETALE®  
lights that make up the generator engine control for a four  
cycle engine.  
(c) Overspeed Speed Switch;  
1. Provides a signal to the overspeed shutdown circuit  
if the engine exceeds the preset speed. The factory  
setting is approximately 3894 Hz, or 1980 RPM on  
an engine with 118 teeth on the flywheel ring gear.  
The adjustment range is 300 Hz to 10,000 Hz.  
6-15/32 in.  
(164 mm)  
2. A push to test switch is provided to allow testing of  
the overspeed circuit without overspeeding the  
engine. When switch is depressed, the set point of  
the speed switch is lowered approximately 10%.  
3. The push to test switch can also be used to set the  
overspeed switch at approximately 110% of running  
speed. Hold the switch depressed while adjusting the  
setting until the overspeed trips. When switch is  
released, the set point will be 10% above normal  
running speed. This is the method used to make the  
factory setting. With engine speed at 1800 RPM or  
3540 Hz.  
Oil Pressure  
Overcrank  
Overspeed  
Lamp Test  
Water  
Temperature  
OFF  
RUN  
9-3/4 in.  
(248 mm)  
START  
3-2.1.4 Eight (8) First-out Shutdown Circuits; provide first-  
out indication of cause of shutdown. These circuits deactivate  
the fuel relay and lockout the MC-900 until reset. Shutdown  
circuits are activated by the Mode Selector Switch and or  
Shutdown Time Delay Bypass. Eight (8) Red Shutdown  
Indicating Lights are provided.  
(a) Overcrank; tripped by the overcrank timing circuit  
which times as long as the START switch is closed.  
(b) Overspeed; tripped by overspeed switch when engine  
exceeds a preset speed.  
(c) Oil Pressure; tripped by the oil pressure SWICHGAGE®  
if pressure drops below preset point while the engine is  
running.  
(d) Water Temperature; tripped by the water temperature  
SWICHGAGE® if engine coolant temperature exceeds  
the switch setting.  
(e) Spare Shutdowns; tripped by an external switch. These  
circuits are provided for additional shutdowns that may  
be recommended by the engine supplier or required by  
the user.  
3-2.2 Relay Module. The Relay Module, figure 3-2.2,  
includes all of the control and shutdown relays that are  
required to make up the generator engine control. Relays are  
available for operation on either 12 or 24 volt battery systems.  
Two (2) relays are included for:  
3-2.2.1 Fuel Relay; this relay provides two outputs, one to  
energize the engine fuel solenoid and a separate circuit to  
energize the battery charging alternator field.  
3-2.2.2 Shutdown Relay; this relay is operated by the  
shutdown circuits of the Control / Display Module and  
provides an output that can be used to trip the generator circuit  
breaker on an emergency shutdown.  
3-2.3 Status Signal; The relay module also includes an output  
that can be used with external circuits for signaling or control  
functions.  
Figure 3-2.1  
3-2.1.1 Mode Selector Switch, OFF-RUN-START:  
(a) OFF; turns off the control system and resets any  
shutdown circuits.  
(b) RUN; turns on the engine controls and shutdown  
circuits. System is on, waiting for the engine to start.  
Switch returns to run position from START after starting  
engine.  
(c) START; turns on the engine start circuit. A start signal is  
applied to the auxiliary start solenoid and the engine  
starter engages. Releasing the start switch disconnects  
cranking.  
3-2.1.2 Lamp Test Pushbutton: Tests the lights on the MC-900  
module when the Mode Selector Switch is in the RUN  
position.  
3-2.1.3 The MC-900 SELECTRONIC® Control Module  
includes the following engine control features:  
(a) Overcrank circuit; will stop manual cranking and  
indicate overcrank if start switch remains closed longer  
than the overcrank time setting. The crank time is  
selectable for 10, 15, 20, 25 or 30 seconds before  
shutdown.  
(b) Shutdown Time Delay Bypass; this delay prevents the  
oil pressure and water temperature shutdown circuits  
from operating for 30 seconds after the engine starts as  
detected by the Mode Selector Switch returning to RUN  
3-2.3.1 The Run signal at terminal 17 is on (closed to  
negative) as long as the Mode Selector Switch is in either Run  
2
 
shutdown. This relay provides an output to trip an air shut off  
solenoid to close the air damper on a two cycle engine.  
3-2.3 Status Signal; The relay module also includes an output  
that can be used with external circuits for signaling or control  
functions.  
J1  
J2  
WARNING  
For continued protection against  
fire & shock hazard, replace only  
with same type fuse & rating.  
TB1  
TB2  
1
4
15  
4
3AMP Fuse  
5
16  
17  
18  
19  
20  
21  
22  
3-2.3.1 The Run signal at terminal 17 is on (closed to  
negative) as long as the Mode Selector Switch is in either Run  
or Start and no shutdown TATTLETALE® circuit is latched on.  
This can be used to signal that the generator engine is ready to  
start or is running.  
6
RH2V2  
-U  
RH2V2  
-U  
7
DC12V  
DC12V  
6-1/4 in.  
(159 mm)  
8
9
10  
11  
12  
23  
24  
13  
14  
Section 4: Installation  
4-1 Location.  
25  
Torque  
Terminal  
12 lbs  
Torque  
Terminal  
12 lbs  
4-1.1 The MC-900 series is designed to mount in a  
MURPHYMATIC® Generator Control panel with the Control /  
Display module on the front panel and the Relay module on  
the inside bottom surface. Other types of installation is  
possible as long as the relationship of the two modules are  
maintained.  
4-1.2 Clearance for Installation and Service; The modules  
must be accessible for wiring to the terminal blocks and  
adjustment of the user controls on the back of the Control /  
Display module. Figure 4-1.2 shows the mounting dimensions  
and the minimum clearances recommended for installation.  
4-1.3 Wiring Terminals; Terminal blocks are provided on  
both sides of the Control / Display enclosure and the Relay  
Module. Torque all terminal screws to 12 inch pound  
maximum.  
4-1/2 in.  
(114 mm)  
Figure 3-2.2  
or Start and no shutdown TATTLETALE® circuit is latched on.  
This can be used to signal that the generator engine is ready to  
start or is running.  
3-3 MC-900-2.  
3-3.1 Control / Display Module. The Control / Display  
Module, figure 3-2.1, is also used as on the Model MC-900-2.  
3-3.2 Relay Module. The Relay Module, figure 3-3.2,  
includes all of the control and shutdown relays that are  
required to make up the generator engine control. Relays are  
available for operation on either 12 or 24 volt battery systems.  
4-2 Wiring.  
4-2.1 After the MC-900 has been located and installed, the  
wiring connections can be made. This work should be done  
with all electrical power disconnected from the engine. BE  
SURE THAT THE BATTERY IS DISCONNECTED.  
4-2.2 All electrical installation work should be done in  
accordance with the National Electrical Code, NFPA-70, and  
all applicable local codes.  
J1  
J2  
WARNING  
For continued protection against  
fire & shock hazard, replace only  
with same type fuse & rating.  
TB1  
TB2  
1
4
15  
4
3AMP Fuse  
5
16  
17  
18  
19  
20  
21  
22  
6
RH2V2  
-U  
DC12V  
RH2V2  
-U  
DC12V  
4-2.3 In general, the following connections will be made:  
(a) Battery positive and negative.  
7
6-1/4 in.  
(159 mm)  
8
9
(b) Engine run device, such as a fuel shutoff solenoid.  
(c) Engine speed sensor, such as a magnetic pickup or the  
tachometer output of a battery charging alternator.  
(d) Engine starter circuit; an auxiliary starter solenoid is  
required to handle most starter solenoid requirements.  
(e) Shutdown sensing switches as required.  
10  
RH2V2  
11  
12  
-U  
DC12V  
23  
24  
13  
14  
25  
Torque  
Terminal  
12 lbs  
Torque  
Terminal  
12 lbs  
4-2.3.1 The complete wiring of a Model MC-900 control is  
shown in figure 4-2.3.1. Provision is made in the MC-900  
series to operate remote lights for all of the shutdown circuits  
however these circuits do not have to be wired for the MC-900  
to function.  
4-1/2 in.  
(114 mm)  
Figure 3-3.2  
4-2.3.2 Figure 4-2.3.2 is for wiring of the MC-900-2 control.  
The same provisions as for the MC-900 are made.  
4-2.3.3 Wire Termination; the terminal blocks that are  
supplied requires that all wires be terminated with #6 stud size  
forked spade solderless wire connectors or stripped and  
inserted under the captive terminal plates. Torque all terminal  
screws to 12 inch pound maximum.  
Three (3) relays are included for:  
3-3.2.1 Fuel Relay; this relay provides two outputs, one to  
energize the engine fuel solenoid and a separate circuit to  
energize the battery charging alternator field.  
3-3.2.2 Shutdown Relay; this relay is operated by the  
shutdown circuits of the Control / Display Module and  
provides an output that can be used to trip the generator circuit  
breaker on an emergency shutdown.  
4-2.3.4 All inductive loads (relays-soleniods-coils-etc.) that  
are connected to the MC-900 must have reverse diodes wired  
3-3.2.3 Overspeed Relay; operates only on an Overspeed  
3
 
Figure 4-1.2: Dimensions  
6 in.  
(152 mm)  
3 in.  
(76 mm)  
2-13/16 in.  
(71 mm)  
5-5/8 in.  
(143 mm)  
1-1/2 in.  
(38 mm)  
clearance  
Mounting  
Holes  
1/8 in.  
(3 mm)  
diameter  
1-1/2 in.  
(38 mm)  
clearance  
6-3/4 in.  
(171 mm)  
3-3/8 in.  
(86 mm)  
4-15/32 in.  
(114 mm)  
9-3/8 in.  
(238 mm)  
5 in. (127 mm) maximum  
between MC-900 and relay module  
3/16 in.  
(5 mm) dia.  
4 places  
NOTE:  
Clearance  
required for  
wire run.  
5-1/2 in.  
(140 mm)  
1-7/8 in.  
(48 mm)  
clearance  
3-3/4 in.  
(95 mm)  
1-7/8 in.  
(48 mm)  
clearance  
4
 
Figure 4-2.3.1: MC-900 wiring  
Hourmeter  
+
Voltmeter  
B+  
Input  
Output  
Barrier  
Terminal  
Blocks  
+
Barrier  
Terminal  
Blocks  
MANUAL START  
MODULE  
15 FUSE B+ OUT  
OVERCRANK LIGHT OUTPUT 35  
OVERSPEED LIGHT OUTPUT  
B– TO HOURMETER  
B GROUND  
26  
4
36  
LOW OIL PRESS. LIGHT OUTPUT 37  
38  
27  
MAGNETIC PICKUP  
HIGH WATER TEMP. LIGHT O/P  
28 LOW OIL PRESS.  
GROUND  
SPARE #1 LIGHT OUTPUT 39  
SPARE #2 LIGHT OUTPUT 40  
4
29 HIGH WATER TEMP.  
30 SPARE #1 SHUTDOWN INPUT  
41  
42  
31 SPARE #2 SHUTDOWN INPUT SPARE #3 LIGHT OUTPUT 43  
32 SPARE #3 SHUTDOWN INPUT SPARE #4 LIGHT OUTPUT 44  
33 SPARE #4 SHUTDOWN INPUT  
34  
45  
46  
Battery  
Auxiliary Starter  
Solenoid  
Starter  
J1 A B  
A B C D E J2  
Lamp  
TB1  
1
4
5
6
7
8
9
10  
11  
12  
13  
14  
TB2  
15  
4
B+  
3A Fuse  
B– Ground  
(FR) Energize to Stop solenoid  
(FR) Energize to Run solenoid  
B+ to aux. starter solenoid  
16  
17  
18  
19  
20  
21  
22  
23  
24  
25  
Run signal switched B–  
Fuel relay N.C. dry contact  
Fuel relay Com. dry contact  
Shutdown relay N.C. dry contact  
Shutdown relay COM. dry contact  
Shutdown relay N.O. dry contact  
Overspeed relay N.C. dry contact  
Overspeed relay COM. dry contact  
Overspeed relay N.O. dry contact  
Shut  
Fuel  
Relay  
J2  
B
J2  
A
Down  
Relay  
Fuel relay N.O. dry contact  
(SDR) Circuit breaker shunt trip  
Over  
Speed  
Relay  
J2  
C
5
 
Figure 4-2.3.2: MC-900-2 wiring  
Hourmeter  
+
Voltmeter  
B+  
Input  
Output  
Barrier  
Terminal  
Blocks  
+
Barrier  
Terminal  
Blocks  
MANUAL START  
MODULE  
15 FUSE B+ OUT  
OVERCRANK LIGHT OUTPUT 35  
OVERSPEED LIGHT OUTPUT  
B– TO HOURMETER  
B GROUND  
26  
4
36  
LOW OIL PRESS. LIGHT OUTPUT 37  
38  
27  
MAGNETIC PICKUP  
HIGH WATER TEMP. LIGHT O/P  
28 LOW OIL PRESS.  
GROUND  
SPARE #1 LIGHT OUTPUT 39  
SPARE #2 LIGHT OUTPUT 40  
4
29 HIGH WATER TEMP.  
30 SPARE #1 SHUTDOWN INPUT  
41  
42  
31 SPARE #2 SHUTDOWN INPUT SPARE #3 LIGHT OUTPUT 43  
32 SPARE #3 SHUTDOWN INPUT SPARE #4 LIGHT OUTPUT 44  
33 SPARE #4 SHUTDOWN INPUT  
34  
45  
46  
Battery  
Auxiliary Starter  
Solenoid  
Starter  
J1 A B  
A B C D E J2  
Lamp  
TB1  
1
4
5
6
7
8
9
10  
11  
12  
13  
14  
TB2  
15  
4
B+  
3A Fuse  
B– Ground  
(FR) Energize to Stop solenoid  
(FR) Energize to Run solenoid  
B+ to aux. starter solenoid  
16  
17  
18  
19  
20  
21  
22  
23  
24  
25  
Run signal switched B–  
Fuel relay N.C. dry contact  
Fuel relay Com. dry contact  
Shutdown relay N.C. dry contact  
Shutdown relay COM. dry contact  
Shutdown relay N.O. dry contact  
Overspeed relay N.C. dry contact  
Overspeed relay COM. dry contact  
Overspeed relay N.O. dry contact  
Shut  
Fuel  
Relay  
J2  
B
J2  
A
Down  
Relay  
Fuel relay N.O. dry contact  
(SDR) Circuit breaker shunt trip  
Over  
Speed  
Relay  
(OSR) Air damper solenoid  
J2  
C
Fuel  
Pressure  
6
 
across the coil to suppress reverse voltage that is generated 4-4.1.2 All of the adjustments and controls shown in Table 4-  
whenever the inductive load is de-energized. This will protect 4.1 are located on the rear of the control/display module. See  
the electronic components in the MC-900 and should prevent Figure 4-4.1.2. Each light and switch is labeled for ease of  
operating malfunction due to noise. The “rule of thumb” for identification. The LED’s are supplied as an aid in installation  
sizing the reverse diode is to use one with a PIV (Peak Inverse and troubleshooting of the MC-900.  
Voltage) rating equal to the operating voltage or at least 100  
volts and a current rating that is equal to or greater than the  
Figure 4-4.1.2  
forward current that the coil draws to operate. For example, a  
relay less than 1 A, use a 1 A diode since they are readily  
available. The wiring shown in figures 4-2.3.1 and 4-2.3.2 have  
examples of the places that a reverse diode is required.  
Fuel Relay  
Torque  
Scews to  
12 In./lb.  
Torque  
Scews to  
12 In./lb.  
15  
35  
Crank Relay  
4-3 Overspeed Switch.  
4-3.1 A magnetic pickup is recommended to supply the speed  
signal for the MC-900 series overspeed switch. This pickup  
will be mounted in the flywheel housing in line with the ring  
gear on the flywheel and wired to the MC-900 using either a  
twisted pair or a shielded cable to reduce the possibility of  
electrical noise pickup in the wiring.  
4-3.2 The tachometer terminal, of the battery charging  
alternator, may be used for the speed signal but a broken drive  
belt will disable this source and some alternators have  
electrical noise which will cause the speed switches to operate  
at speeds well below the desired RPM.  
26  
04  
27  
28  
04  
29  
30  
31  
32  
33  
34  
36  
37  
38  
39  
40  
41  
42  
43  
44  
45  
46  
Crank  
Time  
Lockout  
for start T.D.  
SW1 = 10 s.  
SW2 = 15 s.  
SW3 = 20 s.  
SW4 = 25 s.  
SW5 = 30 s.  
CLOSE  
PUSH  
OPEN  
SW1 = Oil Pr  
SW2 = Wt Tem  
SW3 = Spare #1  
SW4 = Spare #2  
SW5 = Spare #3  
SW6 = Spare #4  
1
0
2
N
3
4
5
1
0
2
N
3
4
5
6
7
Close Only One  
Pickup  
Present  
4-4 Pre-operational Check-out.  
4-4.1 After installation is complete, it is necessary to make  
some adjustments to the MC-900 SELECTRONIC® Control  
before the system is operational. All shutdown circuits also  
should be tested. Table 4-4.1 lists the standard factory setting  
of the adjustable functions on the MC-900 series control. To  
determine if the frequency of the speed switch must be  
changed, calculate the required setting using the following  
formulas:  
Overspeed Overspeed Overspeed Overspeed  
Test Set Relay  
Shutdown  
Relay  
No. of Gear Teeth x RPM set points  
60  
Set point  
frequency in HZ  
=
OR  
Pulley ratio x No. of Alternator Poles x RPM set points  
60  
Set point  
frequency in HZ  
=
Refer to Table 4-4.1 to determine if the speed switch setting is  
below the factory setting listed. If required frequency will be  
higher than the standard, increase the setting before  
proceeding. Turn the Overspeed Set pot clockwise to increase  
setting. The adjustment is a 20 turn control without stops at  
either end.  
Table 4-4.1  
Standard  
Setting  
Adjustment  
Range  
Adjustment  
Type  
Function  
Crank Time  
Overspeed  
15  
seconds  
10, 15, 20, 25  
and 30 Seconds  
Switch  
Pot. 500 Hz per  
turn CW to increase  
3894 Hz  
300 to 10 KHz  
SW1, SW2  
Closed  
SW3, 4, 5, 6  
Open  
4-4.2 Start and Stop Engine; to test the start and stop function,  
proceed as follows:  
Lockout  
for Start  
Switch  
(a) Double check all wiring to be sure it is connected.  
(b) Turn Mode Selector switch to the START position.  
(c) Engine should crank and start. Return switch to RUN  
position.  
4-4.1.1 Be sure to have a fully charged battery to do these  
tests. Low battery voltage can cause improper results during  
the tests.  
(d) When engine has come up to speed and governor has  
7
 
been adjusted for proper running speed, turn Mode  
Selector switch OFF.  
the engine by turning the Mode Selector switch to RUN  
position.  
(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.  
(c) To test other shutdowns, a jumper wire can be used to short  
the input terminal for that circuit, to ground, terminal 4.  
4-4.3 Overspeed Switch Setting; To set the speed switch, Section 5: Operation  
proceed as follows:  
(a) Turn Mode Selector switch to the START position.  
5-1 Operator Controls.  
5-1.1 Mode Selector Switch; allows the operator to start the  
(b) Engine should crank and start. Return switch to RUN engine (START), run the engine (RUN), or stop the engine  
position. (OFF).  
(c) With engine running, adjust governor to bring engine 5-1.2 The OFF position on the mode selector also provides a  
speed to normal RPM.  
(d) Depress and hold the Overspeed Test pushbutton.  
reset function for the shutdown circuits. If the engine is shut  
down by the automatic control, the operator must turn selector  
(e) Slowly turn the Overspeed Set adjustment counter- off and back on to reactivate the system.  
clockwise until the “Overspeed” and “Overspeed Relay” 5-1.3 Push to Test Lamps; this pushbutton tests the shutdown  
lights on the MC-900 come on and the engine shuts indicator lights.  
down.  
(f) Release pushbutton; check “Overspeed” light on front  
panel to be sure it is on.  
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  
(g) Turn Mode Selector switch OFF to reset shutdown  
sensed failure of one of the monitored inputs.  
circuits.  
5-2.2 Manual electric start is provided for operation of the  
(h) Restart engine, when engine starts, increase governor  
generator set.  
speed setting slowly until engine shuts down on  
overspeed. This should occur about 10% above  
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  
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  
engine, turn selector switch OFF.  
Relay Module.  
5-2.3.1 The OFF position is used as a reset for any automatic  
(b) Check time set on the “Crank Time” switch on MC-900  
shutdown that occurs.  
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  
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.  
8
 
7-1.2 Other tools which may be required are:  
7-2.3 With the Mode Selector switch in the RUN position, six of  
7-1.2.l AC/DC Voltmeter for taking voltage readings and an the eight shutdown TATTLETALE® circuits are activated and  
Ohmmeter for testing resistance of wires and connections.  
7-1.2.2 Jumper wires with alligator clips to bypass or simulate  
circuit closures.  
DO NOT USE THESE JUMPER WIRES TO CHECK IF  
VOLTAGE IS PRESENT AT A TERMINAL BY DRAWING  
AN ARC TO GROUND. THIS WILL DAMAGE OR  
DESTROY EQUIPMENT IN THE MC-900 CONTROL  
PANEL.  
will operate anytime a switch closes from ground to their inputs.  
Circuit  
Input  
Output  
(a) Oil Pressure  
(b) Water Temp  
(c) Overspeed*  
(d) Overcrank**  
(e) Spare Shutdown #1  
(f) Spare Shutdown #2  
(g) Spare Shutdown #3  
(h) Spare Shutdown #4  
Terminal 28  
Terminal 29  
Int. Speed Switch  
Int. Circuit  
Terminal 30  
Terminal 31  
Terminal 32  
Terminal 30  
Terminal 37  
Terminal 38  
Terminal 36  
Terminal 35  
Terminal 39  
Terminal 40  
Terminal 43  
Terminal 44  
7-2 MC-900 SELECTRONIC® Control Operation and  
Shutdown.  
7-2.1 The first step in troubleshooting any equipment is to  
understand its normal operation. Table 7-2.1 contains normal  
voltage readings taken at the terminals of the MC-900 with all  
equipment shown on the standard drawing, connected.  
(a) All voltage readings are DC, except at terminal 27, and  
were taken with the negative lead of the meter connected  
to ground at terminal 4. Voltage reading at terminal 27  
was taken with negative lead grounded and the meter on  
AC scale.  
(b) The battery voltage, at the time readings were recorded,  
was 13.8V and 27.6V. All readings will vary depending  
on battery voltage, equipment supplied in the panel and  
external devices connected to the MC-900 control. See  
notes to the table for examples.  
(c) Voltages less than battery also may vary due to  
tolerances of the electronic components in the MC-900.  
Minor variations, 1 or 2 volts, normally will have no  
effect on the MC-900 operation.  
(d) The AC voltage at terminal 27 must be a minimum of 2  
VAC to drive the speed sensing circuits of the MC-900.  
7-2.2 With power applied and the Mode Selector switch in  
OFF, the following occurs when the switch is moved to the  
START position.  
7-2.2.1 The fuel relay is energized, which opens the circuits at  
terminal 5 and 7, and closes the circuits at terminal 6 and 9.  
This applies battery power to the run solenoid and to the  
exciter terminal of the alternator (if used).  
7-2.2.2 At the same time, the crank relay driver provides  
battery voltage at terminal 16 to the auxiliary starter solenoid.  
This output is controlled by the Mode Selector switch and the  
Overcrank timer. The output will remain on until the Mode  
Selector switch is returned to RUN or the Overcrank time  
expires.  
*Engine must be running to operate speed switch  
**Circuit operates only while cranking  
7-2.3.1 Each circuit has a indicating light and a transistor  
output that closes to ground to operate an individual remote  
indicating light.  
7-2.3.2 When any of the eight shutdown functions trip, the  
shutdown relay K-2, pulls in and applies battery power to  
terminal 10. At the same time, the fuel relay, K-1 drops out  
and if the shutdown was due to overspeed, the overspeed relay,  
K-3 pulls in to signal an air shut off solenoid, terminal 11 to  
close.  
7-2.3.3 The eight shutdown circuits, paragraph 7-2.3, are first  
out latching type TATTLETALES®. That is, only one of the  
eight may trip at one time and it must be reset before the MC-  
900 will operate again.  
7-2.3.4 If one of the TATTLETALE® circuits trip, the  
following occurs to shutdown the engine and generator.  
(a) The TATTLETALE® light for that function turns on.  
(b) Shutdown relay K-2 is energized, closing its contacts at  
terminal 10. These contacts can be wired to a shunt trip  
solenoid in the generator circuit breaker if required.  
(c) The fuel relay drops out, removing battery voltage from  
the run solenoid, terminal 6. The circuit at terminal 5  
will close to reconnect the battery positive to this  
terminal.  
(d) The run signal, terminal 17 turns off.  
(e) If the shutdown is due to overspeed, the overspeed relay  
operates and applies battery positive to terminal 11 to  
close an air shutoff solenoid if the engine is so equipped.  
7-2.3.5 The dry contacts of relay K-1, at terminals 7, 8 and 9;  
relay K-2, at terminals 18, 19 and 20; and relay K-3, at  
terminals 20, 21 and 22; change state when the relays operate.  
7-2.3.6 To reset the circuits, the Mode Selector switch must be  
turned OFF.  
7-2.2.3 If the engine does not start during the Overcrank time,  
the overcrank shutdown circuit trips and removes the output to  
the starter solenoid. The Mode Selector switch must be turned  
OFF to reset the shutdown circuit.  
7-2.4 Normally, the engine will run until the Mode Selector  
switch is turned OFF.  
7-2.4.1 When this happens, the following occurs to stop the  
engine;  
(a) The fuel relay drops out, removing battery voltage from  
the run solenoid. The circuit at terminal 5 will close to  
reconnect the battery positive to this terminal.  
(b) The run signal, terminal 17 turns off.  
(c) The TATTLETALE® circuits are locked out as soon as  
the switch is turned OFF. This prevents any  
TATTLETALE® from tripping while the engine coasts to  
a stop.  
7-2.2.4 When the engine starts and the Mode Selector switch  
is returned to the RUN position,  
(a) Cranking is terminated.  
(b) A time delay starts timing during which the oil pressure  
and water temperature shutdown circuits are locked out.  
(c) The overcrank timer is reset to zero.  
(d) The overspeed shutdown circuit is activated.  
7-2.2.5 An engine run signal closes to ground at terminal 17  
when the Mode Selector switch is in the RUN position and the  
engine is not shutdown by the MC-900 shutdown circuits.  
9
 
Table 7-2.1  
Mode  
Selector  
OFF  
Mode Selector Mode Selector Mode Selector  
START  
RUN  
RUN  
Cranking  
Running  
Shutdown  
Input Voltage Input Voltage Input Voltage Input Voltage  
27.6  
Terminal  
Number  
13.8  
27.6  
13.8  
27.6  
13.8  
27.6  
13.8  
1
4
5
6
13.8  
0
13.8  
0
0
27.6  
0
27.6  
0
0
13.8  
0
0
13.8  
0
27.6  
0
0
27.6  
0
13.8  
0
0
13.8  
0
27.6  
0
0
27.6  
0
13.8  
0
13.8  
0
27.6  
0
27.6  
0
7
0
0
8
0
0
0
0
0
0
0
0
9
0
0
0
0
0
0
0
0
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
22  
23  
24  
25  
26  
27 (1)  
28 (2)  
29  
30  
31  
32  
33  
34  
35  
36  
37 (2)  
38  
39  
40  
41  
42  
43  
44  
45  
46  
0
0
0
0
0
13.8  
0
0
0
0
0
0
0
0
0
0
13.8  
0
0
0
0
0
0
0
0
13.8  
13.8  
13.8  
13.8  
13.8  
13.8  
0
0
0
0
0
0
27.6  
0
0
0
0
0
0
0
0
0
0
27.6  
0
0
0
0
0
0
0
0
27.6  
27.6  
27.6  
27.6  
27.6  
27.6  
0
0
0
0
0
0
0
0
0
0
0
0
0
0
13.8  
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
27.6  
0
0
0
0
0
0
0
0
0
0
0
13.8  
0
0
0
0
13.8  
0
0
0
0
0
0
0
0
0
0
13.8  
0
0
7.5  
7.5  
7.5  
7.5  
7.5  
0
13.8  
13.8  
0
13.8  
13.8  
13.8  
0
27.6  
0
0
0
0
27.6  
0
0
0
0
0
0
0
0
0
0
27.6  
0
0
7.5  
7.5  
7.5  
7.5  
7.5  
0
27.6  
27.6  
0
27.6  
27.6  
27.6  
0
0
0
13.8  
13.8  
0
0
0
0
0
0
0
0
0
0
4
27.6  
27.6  
0
0
0
0
0
0
0
0
0
0
4
4
4
0
0
7.5  
7.5  
7.5  
7.5  
7.5  
7.5  
0
13.8  
13.8  
13.8  
13.8  
13.8  
13.8  
0
7.5  
7.5  
7.5  
7.5  
7.5  
7.5  
0
27.6  
27.6  
27.6  
27.6  
27.6  
27.6  
0
7.5  
7.5  
7.5  
7.5  
7.5  
0
13.8  
13.8  
13.8  
13.8  
13.8  
13.8  
0
7.5  
7.5  
7.5  
7.5  
7.5  
0
27.6  
27.6  
27.6  
27.6  
27.6  
27.6  
0
0
0
0
0
0
0
0
0
13.8  
13.8  
0
27.6  
27.6  
0
13.8  
13.8  
0
27.6  
27.6  
0
13.8  
13.8  
0
27.6  
27.6  
0
13.8  
13.8  
0
27.6  
27.6  
0
0
0
0
0
0
0
0
0
NOTES  
Note 1: AC voltage measured on AC scale of volt-ohmmeter.  
Note 2: Low Oil Pressure shutdown circuit.  
Oil pressure was the cause of shutdown on column 4.  
10  
 
Section 8: Replacement Parts  
8-1 Replacement Parts  
8-1.1 Table 8-1 covers all of the replaceable components of  
the MC-900 Series Generator Engine Controls. The part  
numbers shown are Frank W. Murphy Mfr. part numbers and  
may not appear on the individual parts.  
8-1.2 Each complete control is made up of a Control / Display  
Module, a Relay Module and a number of Relays.  
8-1.3 There are no field replaceable parts in the Control /  
Display Module, the complete module must be replaced if it  
fails. All relays are individually replaceable in the Relay  
Module but the module must be replaced if a failure of the  
circuit board occurs.  
8-2 Replacement Parts Waukesha Modules  
8-2.1 Table 8-2 part numbers are Murphy part numbers for  
MC-900 controls manufactured for Waukesha Corporation.  
These OEM parts are available only to Waukesha and their  
distributors.  
8-2.2 The MC-900 parts are the same as the Murphy MC-900  
series that has been covered through out this manual.  
Table 8-1  
Model Number  
MC-900-12  
MC-900-24  
Part Number  
40-70-0130  
40-70-0177  
40-70-0173  
Control / Display  
Relay Module  
40-00-0091  
40-00-0091  
40-00-0091  
Relay Part  
00-00-2952  
00-00-2953  
00-00-2953  
Relay Qty. Module  
40-00-0023  
40-00-0023  
40-00-0023  
2
2
3
MC-900-2-24  
Table 8-2  
Model Number  
MC-900-2-24  
Waukesha  
Part Number  
40-35-0047  
Control / Display  
40-00-0223  
Relay Module  
40-00-0224  
Relay Part  
00-00-2953  
Relay Qty. Module  
2
CONTROL SYSTEMS & SERVICES DIVISION  
P.O. Box 1819; Rosenberg, Texas 77471; USA  
+1 281 633 4500 fax +1 281 633 4588  
FRANK W. MURPHY, LTD.  
MACQUARRIE CORPORATION  
1620 Hume Highway  
Church Rd.; Laverstock, Salisbury SP1 1QZ; U.K.  
+44 1722 410055 fax +44 1722 410088  
Campbellfield, Vic 3061; Australia  
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FW Murphy  
P.O. Box 470248  
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Blvd. Antonio Rocha Cordero 300, Fracción del Aguaje  
San Luis Potosí, S.L.P.; México 78384  
+52 444 8206264 fax +52 444 8206336  
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MURPHY SWITCH OF CALIFORNIA  
41343 12th Street West  
Palmdale, California 93551-1442; USA  
+1 661 272 4700 fax +1 661 947 7570  
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+1 918 317 4100  
fax +1 918 317 4266  
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In order to consistently bring you the highest quality, full featured products, we reserve the right to change our specifications and designs at any time.  
Printed in U.S.A. 1291185  
11  
 

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