System Operation
Use this procedure to calibrate the crank terminate of the engine speed switch (ESS). This procedure should be performed when the ESS is replaced or when calibration is necessary. Calibration of the crank termination requires a signal generator and a 4C-6534 Adapter Group to simulate a 400 rpm input.
Crank termination is a adjustable setting that signals that the engine is firing. Crank termination also signals when cranking must be terminated. When the crank termination speed is reached, terminal 10 is energized in order to start the engine hour meter.
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| Illustration 1 | g01633296 |
Engine speed switch | |
Set The Crank Termination
- Remove the lockwire and the seal from the access hole for the adjustment screw for the crank terminate.
- Use a screwdriver to lightly turn the adjustment screw for the crank terminate by twenty turns in the clockwise direction.
- Disconnect the engine speed input at ESS terminal 3 and terminal 4.
- Connect a signal generator to ESS terminal 3 and terminal 4. Use 4C-6534 Adapter Harness for the connection.
- Turn the engine control switch to the ON position.
- Adjust the signal generator frequency to 0 Hz. Next, adjust the signal generator frequency to 900 Hz.
- Connect a voltmeter between terminal 10 and terminal 5.
- Slowly rotate the adjustment screw for the crank terminate in the counterclockwise direction. Monitor the voltage between terminal 10 and terminal 5. Stop rotating the screw when the voltage changes to battery positive voltage.
Note: The voltage between ESS terminal 10 and terminal 5 should increase to battery positive voltage when the approximate setting for the crank terminate is reached.
Adjust the Setting for the Crank Terminate
- Set the frequency generator to 0 Hz.
- Slowly increase the frequency. Monitor the voltage between ESS terminal 5 and terminal 10. Record the frequency that causes the voltage to increase to battery positive voltage.
Note: The voltage between ESS terminal 10 and ESS terminal 5 should increase to battery positive voltage when the frequency reaches 875 Hz to 920 Hz.