SEAL 1850883 - Caterpillar

Introduction
The 4C6534 Speed Switch Calibration Harness (1) is now available, and is a replacement for the former 9W6370 Harness. This new harness is for use with the 8T5200 Signal Generator/Counter Group to perform a functional check, and a calibrated check, for an engine electronic speed switch that has two, three, or four elements. The former 9W6370 Harness can still be used with two and three element speed switches, but, it does not provide enough voltage to operate four element speed switches. When using the 9W6370 Harness, it may be necessary to also use the 8T5197 Calibrator Cable.The calibration check and the functional check can not be used on electronic speed switches that provide reverse protection. They require the use of a tachometer drive low mounted speed sensor.Do not perform any procedure, outlined in this publication, or order any parts until you read and understand the information contained within.Reference: Special Instruction form SEHS8579.Using the 4C6534 Speed Switch Calibration Harness to Connect the 8T5201 Signal Generator/Counter to an Electronic Speed Switch
1. Connect 4C6534 Speed Switch Calibration Harness (1) to the OUTPUT connection (2) on 8T5201 Signal Generator/Counter (3). 2. Disconnect magnetic speed sensor wires (4) and (5) at the COM and SIG terminals on electronic speed switch (6). (COM and SIG are terminals 3 and 4 on the electronic speed switch.)Disconnect any other wires that are connected to terminals 3 and 4. The above procedure includes disconnection of electrical wires. Always identify each wire in some manner before it is disconnected. This will aid in the correct connection of all wires after the checks and calibrations are completed.
If the engine is equipped with a Woodward 2301 Governor, and its wiring connects to the same electronic speed switch terminals as the magnetic speed sensor, connect the magnetic speed sensor wires to the Woodward 2301 Governor wires. This will provide additional engine speed control, should it be needed.
3. Connect 4C6534 Speed Switch Calibration Harness (1) to the COM and SIG terminals on electronic speed switch (6).One connecting terminal of harness (1) has a (+) symbol. This terminal must be connected to the SIG terminal. 4. If the engine is equipped with an electrical fuel shutoff solenoid, disconnect the positive (power) wire at fuel shutoff solenoid (7). Use electrical tape, or some other type of insulation, to cover the terminal of the disconnected wire. This will insulate it from the engine so it will not cause an electrical short. 5. Use a voltmeter to measure the DC Voltage supplied to terminals 5 and 6 (8) on electronic speed switch (6). With correct polarity, voltage for all electronic speed switches should be 8 Volts DC minimum, and 40 Volts DC maximum. The engine should NOT be running during the functional check or the calibration check. Take the necessary precautions to make sure the engine will not start.Conversion of Set Point rpm to Hz
1. Before doing any of the checking procedures given in this instruction, refer to the SPEED SPECIFICATION CHART in this instruction for