Engine Micro-Controller
Engine Micro-Controller


  • Microprocessor based automatic controller
  • Field Programable trip points
  • Five LED signal indicators
  • Startup lockout timer
  • Interfaces with other existing Murphy Products
  • NEMA 3R "Weatherproof" enclosure



A completely unattended startup/shutdown and run controller for 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 is designed to operate from a 12 or 24 volt battery, and requires a magnetic sensor (pick-up) 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. Warm up and cool down are connected only on the WC model. 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. Custom programming of the microchip is available to OEM's and quantity orders.


The A91 is housed in a NEMA 3R enclosure with a hinged and gasketed dead front door. This weatherproof enclosure includes two 1/2 in. conduit holes, [7/8 in. (22 mm) diameter] in the bottom for input and output wiring.


All of the electrical components are installed on a "box" shaped, hinged front sub panel assembly. This working assembly can be purchased and installed in the user's choice of enclosures.



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
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