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Murphy Electronic Speed Switch with Low Frequency SS300-LF-12

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Murphy Electronic Speed Switch 12V with Low Frequency - SS300-LF-12

Product Condition: NEW
Murphy Electronic Speed Switch 12V with SPDT Relay Dry Contact Output SS300-LF-12
Estimated ship date: for orders by 3pm PT/6pm ET today Available for back order.

SSL Cerficate

The Murphy 12V with Low Frequency SS300-LF-12 is a single set point speed switch with SPDT relay dry contact output. The trip point is set by a potentiometer. An LED indicates when the signal source is present. A second LED turns on when the trip point is reached. An optional time delay is on board to delay operation of the relay for 2-6 seconds after the set point has been reached. The SS300-LF-12 is intended for installation within a weatherproof enclosure to protect it from rain, dust, etc.

Application: Overspeed shutdown. Shuts down the engine if RPM exceeds the pre-set limit. Speed sensitive pull-in/drop-out. Engage or disengage PTO’s, 4-wheel drives, other switch points, etc. according to speed of engine being monitored. The SS300-LF-12 can select between two pressure switch set points according to speed of the engine or transmission and thus give maximum protection to the equipment while at operating RPM and eliminate nuisance alarms when at idle.



  • Low frequency
  • Single set point
  • Magnetic Pickup
  • Compact design
  • Field adjustable set points
  • High noise immunity



  • Part No.: SS300-LF-12
  • Power Requirements: 12 VDC (9-16 VDC)
  • Frequency Signal: Minimum Input Voltage Signal: 4.5 Vrms • Maximum Input Voltage Signal: 50 Vrms
  • Maximum Current Pull In: 46 mA; Pickup only: 10.5 mA
  • Frequency Range in Hz: 25-2000
  • Reset Differential Alternator (Low Frequency): 2 Hz Differential
  • Output: Relay contact, SPDT, resistive load, 6 A, 30 VDC
  • Time Delay: When terminal 7 is grounded, the relay operation is delayed for 2-6 seconds after rpm set point is reached
  • Adjustment: 20–turn potentiometer(s)
  • Temperature Range: -4° to 185°F (-20° to 85°C)
  • Relative Humidity: 0 to 95% Non-condensing
  • Case: Black, ABS plastic
  • Shipping Weight: 0.24 lb. (108 g)
  • Shipping Dimensions: 8 x 4 x 4-1/2 in. (203 x 102 x 114 mm)

Additional Information

Product Condition NEW
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