Section 1: Introduction
1-1 System.
1-1.1The 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.
1-2.1The Series MC-900 is available in two basic configurations:
1-2.1.1Model MC-900 for manual start and stop generator sets with four cycle engines which includes the minimum normal shutdowns.
1-2.1.2Model 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.
1-2.2Both models are available for 12 or 24 volt operation.
1-2.3Both models include four unlabeled shutdown circuits for additional customer specified shutdowns.
1-2.4Each model is made up of two parts, a Control/Display module and a Relay module.
1-3 Purpose.
1-3.1This manual is directed to the installation, maintenance and operating personnel who will be in day to day contact with the MC-900 system.
1-3.2No 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.
1-4.1Throughout this manual, reference is made to organizations, trade names and trademarks which may not be familiar to the reader. Some of these are:
1-4.1.1NFPA: National Fire Protection Association.
1-4.1.2NFPA-70: The National Electrical Code.
1-4.1.3Several 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.
1-5.1Section 1, 2, 4, 5, 6 and 7 contain general information that applies to all MC-900 models.
1-5.2Section 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.
2-1.1The MC-900 Series enclosure is designed to be mounted in a standard electrical enclosure for indoor use.
2-1.2The MC-900 Series shares the same enclosure as the A- 900 automatic start controller so they can be used interchangeably in a generator control panel.
2-2 Power Requirements.
2-2.1The 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.
2-2.2The MC-900 is fused for 3 amp. maximum current.
2-3 Input Ratings.
2-3.1All input switches should be dry contact type, maximum current is 2 ma, 8 VDC or less.
2-3.2Frequency 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.
2-3.2.1Frequency range of the speed sensing circuit is 300 Hz to 10,000 Hz.
2-4 Output Ratings.
2-4.1The 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.
2-4.2The 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).
2-4.3The 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.
2-5.1All field wiring connections are barrier terminal blocks, UL rated for 15 amp, 300 volt.
2-6 Operating Temperature.
2-6.1The 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.
3-1.1MC-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.
3-1.2MC-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.
3-1.2.1The MC-900-2 series control includes an “Overspeed Relay” to trip the air shut-off solenoid on overspeed of a two cycle engine.
