Murphy MC-900 User Manual
SERIES MC-900 MURPHYMATIC
®
MANUAL GENERATOR
ENGINE CONTROL SYSTEM
DESIGN, INSTALLATION
AND OPERATING MANUAL
MC-9142N
Revised 12-00
Section 40
(00-02-0202)
Table of Contents
Section 1: Introduction page 1
1-1 System ............................................................................................................................................... 1
1-2 Models ............................................................................................................................................... 1
1-3 Purpose .............................................................................................................................................. 1
1-4 Definitions ......................................................................................................................................... 1
1-5 How To Use This Manual ............................................................................................................... 1
Section 2: Specifications 1
2-1 Enclosure Type ................................................................................................................................. 1
2-2 Power Requirements ........................................................................................................................ 1
2-3 Input Ratings .................................................................................................................................... 1
2-4 Output Ratings ................................................................................................................................. 1
2-5 Field Wiring Connections ................................................................................................................ 1
2-6 Operating Temperature ................................................................................................................... 1
Section 3: Model Identification 1
3-1 Model Numbers ................................................................................................................................ 1
3-2 MC-900 .............................................................................................................................................. 2
3-3 MC-900-2 .......................................................................................................................................... 3
Section 4: Installation 3
4-1 Location ............................................................................................................................................ 3
4-2 Wiring ............................................................................................................................................... 3
4-3 Overspeed Switch ............................................................................................................................. 7
4-4 Pre-Operational Check-Out ............................................................................................................ 7
Section 5: Operation 8
5-1 Operator Controls ............................................................................................................................ 8
5-2 Operating Modes .............................................................................................................................. 8
Section 6: Routine Maintenance and Operational Tests 8
6-1 Routine Maintenance ....................................................................................................................... 8
6-2 Operational Tests ............................................................................................................................ 8
Section 7: Troubleshooting and Repair ...................................................................................... 8
7-1 Tools Required .................................................................................................................................. 8
7-2 MC-900 SELECTRONIC®Control Operation and Shutdown ................................................... 9
Section 8: Replacement Parts 11
8-1 Replacement Parts ........................................................................................................................... 11
8-2 Replacement Parts Detroit Diesel Modules ................................................................................... 11
Section 1: Introduction
1-1 System.
1-1.1 The MURPHYMATIC®Manual Generator Engine
Control System, Series MC-900 is designed to meet the
requirements of the engine control and shutdown for manual
start generator engines.
By combining one of the MC-900 series controls with generator
instruments, a complete engine generator control panel can be
provided.
1-2 Models.
1-2.1 The Series MC-900 is available in two basic
configurations:
1-2.1.1 Model MC-900 for manual start and stop generator sets
with four cycle engines which includes the minimum normal
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.
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.
1-4 Definitions.
1-4.1 Throughout this manual, reference is made to
organizations, trade names and trademarks which may not be
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.
(a) MURPHYMATIC®: Refers to all Murphy automatic
controls.
(b) SELECTRONIC®: A name that is applied to all electronic
controls manufactured by Murphy.
(c) SWICHGAGE®: A combination indicating gauge and
switch.
(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.
Section 2: Specifications
2-1 Enclosure Type.
2-1.1 The MC-900 Series enclosure is designed to be mounted
in a standard electrical enclosure for indoor use.
2-1.2 The MC-900 Series shares the same enclosure as the A900 automatic start controller so they can be used
interchangeably in a generator control panel.
2-2 Power Requirements.
2-2.1 The engine controls, shutdown circuits and shut-down
indicators are powered from the engine starting battery. The
MC-900 series is available in either 12 or 24 volt, negative
ground.
2-2.2 The MC-900 is fused for 3 amp. maximum current.
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.
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
(source).
2-4.3 The Relay Module includes 3 engine control relays with
contact ratings of 7 amp, 30 VDC inductive. These powered
contacts must be suppied from an 8 amp. fuse or circuit breaker
(customer supplied).
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.
Section 3: Model Identification
3-1 Model Numbers.
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.
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.
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.
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
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.
(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.
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.
3-2.1.4 Eight (8) First-out Shutdown Circuits; provide firstout 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.
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
Figure 3-2.1
6-15/32 in.
(164 mm)
Oil Pressure
Water
Temperature
9-3/4 in.
(248 mm)
Overcrank
Overspeed
Lamp Test
OFF
RUN
START
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