Operation Check
- Make all power connections. Put the load controller in the MANUAL position. This will power the next stage (control handle or control valve) regardless of engine RPM.
Note: If the hydrostatic transmission fails to operate after having previously run properly, any one of the system components could be the problem source. All load controllers tests should be run on HIGH output setting.
- Attach a volt-ohmmeter across the valve terminals of the controller. If the volt-ohmmeter reads less than 11 volts, the problem is in the electrical power supply.
- If the normal electrical output is displayed, the handle, the valve and the transmission should function properly. If the normal electrical output is not displayed, the handle, the valve or the transmission is the source of the problem.
- If the voltage across the load controller output is full in the MANUAL position but low in the AUTO position, unscrew the front plug for the set point for the RPM. Observe the set point on the LCD. In the unloaded conditions (high RPM), the light should be out.
- If the LCD is on, put the volt-ohmmeter across the alternator connection. The volt-ohmmeter will read approximately 7 volts. This indicates that the alternator is actually connected.
- If the alternator voltage is low, check the alternator belt. A loose belt or a broken belt should be replaced.
- If the above problems are not the cause, the load controller is not serviceable in the field. Replace the unit.
Sensitivity Adjustment
- Set sensitivity knob (1) to the fifth mark toward MAX.
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| Illustration 1 | g00762295 |
Load Controller (1) Sensitivity knob (2) Screws | |
- Begin normal operation.
- If you feel lurching in the machine, reduce the sensitivity.
- If necessary, Repeat Step 3.
Adjustment of the Set Point for the RPM
The set point is adjusted through a 25 turn potentiometer that is accessed through an opening in the front panel of the controller. Adjusting the set point requires a digital multimeter.
When you adjust the load controller, the output must be against a load. Therefore when you measure voltage of the controller output, the propel control must be in the full FORWARD position or the full REVERSE position.
- Place the propel transmission in the NEUTRAL position. Apply the parking brake.
- Make sure that the ignition switch is in the OFF position.
- Remove two screws (2) and the load controller.
- Remove pipe plug (3) from the face of the load sensor in order to access the engine load sensing potentiometer.
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| Illustration 2 | g00762312 |
Load Controller (3) Plug (4) AUTOMATIC/MANUAL switch | |
- Connect the positive lead of a digital multimeter to "Valve Positive +" terminal (6) .
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| Illustration 3 | g00762314 |
Output Terminals (5) "Valve Negative -" terminal (6) "Valve Positive +" terminal | |
- Connect the negative lead of a digital multimeter to "Valve -" terminal (5) .
- Set AUTOMATIC/MANUAL switch (4) to the AUTOMATIC position.
- Adjust the sensitivity dial to the midpoint. When the sensitivity knob is set slightly above the midpoint or below the midpoint, adjusting the controller will have very little impact on the starting of the controlling cycle. Shifting the sensitivity knob from the midpoint will noticeably affect the relationship between the engine RPM and the minimum voltage output of the controller.
When you set the sensitivity adjustment close to the maximum setting, the engine RPM is higher at the minimum voltage output.
- Place speed selector switch (7) in the HIGH range.
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| Illustration 4 | g00762317 |
Load Controller (7) Speed selector switch | |
- Start the engine. Allow adequate time for the engine to warm up.
- Use a phototach to adjust the engine speed to 2100 rpm.
- Adjust the potentiometer for 22 volts. Move the propel control to the NEUTRAL position and then move the propel control back to the TRAVEL position. If necessary, readjust the potentiometer to 22 volts.
Leave the engine at 2100 RPM and the propel transmission in neutral. Move the propel control to the NEUTRAL position. Select the medium range of the range control. Move the propel control to the full stroke. Voltage out of the controller should read 60% of 22 volts or 13.2 ± 1 volt.
With the engine at 2100 RPM and the propel transmission in neutral, select the low range on the range control and stroke the propel control to the full stroke. Voltage out of the controller should read 30% of 22 volts or 6.6 ± .5 volts.
Note: Stroke the propel control at each shift. False voltage readings are encountered if the propel control is not stroked during the shift cycle.
Note: Engine RPM must be maintained at 2100 RPM. Any loss or gain of RPM could result in incorrect voltage reading in the medium or low ranges.
Note: If adjusting the potentiometer does not bring the voltage up to the specified 22 volts, verify that 24 volts are being supplied to the battery positive terminal on the load controller. If adjusting the potentiometer does not bring the voltage up to 22 volts, the load controller should be replaced.
- Reduce the engine RPM.
- Turn the engine off.
- Disconnect the multimeter.
- Install the pipe plug into the load controller after applying a thread sealant. Tighten the plug until the plug is tight. Do not tighten until the plug bottoms out.
- Install the load controller and two screws.
- After adjusting the set point for the RPM, the sensitivity dial may need to be readjusted until the desired operating characteristics are attained.
Note: The engine load sensing system is preset. The system should only be adjusted when you replace a worn unit or a damaged unit.