723PLUS Digital Speed Control Caterpillar

Perform the following check procedure, when the installation that is described in this manual has been completed. Perform this procedure before you enter set points or before you make the initial start up adjustments.

Note: The actuator lever should be near the minimum position but the actuator lever should not be at the minimum position when the fuel valve or the fuel rack is at the minimum fuel delivery position.

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The engine may overspeed due to incorrect assembly or adjustment. Engine overspeed could result in personal injury, loss of life and/or property damage. Be prepared to stop the engine by activating the engine shutdown system or closing the air inlet lines.

1. Visually inspect the following items:
   • Check the linkage that is between the actuator and the device that is used to meter fuel. Make sure that the linkage is not loose and make sure that the linkage does not bind. Refer to the manual for your actuator.

   • Check with the wiring diagram for the correct wiring. See this Service Manual for the topic "Electrical Connections".

   • Check for broken terminals and loose terminal screws.

   • Check the speed sensor(s) for visible damage. If necessary, check the clearance between the gear and the sensor and adjust the clearance, if the sensor is a magnetic pickup. Clearance should be between 0.75 ± 0.50 mm (0.03 ± 0.02 inch) at the closest point. Make sure that the gear runout does not exceed the gap between the gear and the pickup. The pickup will not produce a signal which will meet the requirement, if the gap is too big. The requirements can be found in the "Electrical Connections" section.

2. Check for grounds

Check for grounds by measuring the resistance from all control terminals to chassis. All terminals should measure infinite resistance. The resistance of terminals 2 and 37 depends on the method that is used to ground the power source. If the resistance is less than infinity, remove the connections from each terminal one at a time until the resistance is infinite. Check the line that was removed last in order to locate the fault.