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Murphymatic Engine Micro-Controller Less Case A91-12-LC

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Murphymatic Engine Micro-Controller 12 VDC - Less Case - A91-12-LC

Product Condition: NEW
Murphymatic Engine Micro-Controller 12 VDC A91-12-LC
Estimated ship date: for orders by 3pm PT/6pm ET today Available for back order.

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The Murphymatic Engine Micro-Controller 12 VDC Less Case A91-12-LC is a state-of-the-art, automatic engine controller. It is used to automatically start and stop internal combustion engine driven equipment. This user friendly, compact, state-of-the-art microprocessor based controller, covers all basic start stop operations plus other features only found on more sophisticated and expensive controllers. The A91-12-LC is designed to operate from a 12 volt battery and requires a magnetic sensor (pickup) for speed detection. It includes features, such as crank and rest cycles, time delay lockouts, sensing circuit for crank disconnect and overspeed, time delays before start and stop.

Four LED’s indicate shutdown for: low lube oil, high temperature, over crank and overspeed and are reset by turning the power off. A fifth LED for engine running indicates when crank disconnect occurs. The micro-controller is available in several configurations and is factory programmed. Certain parameters can be field adjusted without altering the basic control program.

A variety of applications can be covered with the micro-controller such as: Air/Gas Compressors • Standby Generator Sets • Fire/Pipeline/Emergency Flood Pumps • Booster/Transfer Pumps • Municipal Fresh/Waste Water Treatment • Sewage Lift Stations


  • Less Case (enclosure)
  • For less than 5 amp current draw up to
  • 24 VDC electric run output
  • Microprocessor Based Automatic Controller
  • Field Programmable Trip Points
  • Five LED Signal Indicators
  • Startup Lockout Timer
  • Applicable to All Types of Engines
  • Quality 16 point Terminal Block
  • Relays are plug-in type with LED indicator for fast service and maintenance
  • Either start from remote contact close to start, open to stop, or N.O. contacts close to start, close to stop
  • Three-position Selector Switch allows for “Automatic”, “Off” or “Test” mode
  • Built-in Speed Sensing Circuit with Adjustable Crank Disconnect RPM and Adjustable Over speed RPM


  • Part No.: A91-12-LC
  • Power Input: 12 VDC nominal
  • Standby Power Consumption: <50mA
  • Magnetic Pickup Input: Requires 2 V rms minimum
  • Sensor Input Polarity: Negative (-)
  • Outputs: Five (5) open collector transistor 500 mA sink. Two (2) relay, 5 Amp maximum at 12 or 24 VDC (sourcing)
  • Reverse Polarity Protection: 200 volt peak reverse voltage
  • On-board Memory: 8k PROM (programmable, read only memory); data retention 10 years
  • Operating Temperature Range: -20 to 140°F (-25 to 60°C)
  • Operating Humidity Range: 0-95% Non-Condensing
  • User Trip point Adjustments: Five (5) on-board potentiometers (320° turn)
  • Test-Off-Automatic Toggle Switch: Three position switch for: Test: Starts engine in automatic mode and runs until switched “off” or
  • emergency shutdown occurs ● Off: Disconnects all power to control circuits, Stop/disables engine from starting and resets shutdown indicators ● Auto: Automatic start/stop sequencing is initiated by external switches and signals
  • Cycle Crank Timer: 5 crank attempts 7 seconds each; 4 rest periods 15 seconds each, before overcrank
  • Overspeed Trip Point Setting: From 2500-9000 Hz
  • Crank Disconnect Speed Setting: From 400-2500 Hz
  • Shutdown Time Delay: 15 seconds after engine start; locks out low lube oil and high temperature
  • Engine Run LED: Turns“on”when crank disconnect occurs
  • Shutdown Output: Removes DC output or operates dry relay contacts for engine shutdown (depending on model used)
  • Start/Stop: SPDT momentary; or SPST maintained switches
  • Shipping Weight: 17 lb. (8 kg); subpanel: 7 lb (3.2 kg)
  • Shipping Dimensions: 12 x 12 x 9 in. (305 x 305 x 229 mm)

Additional Information

Product Condition NEW
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