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| Illustration 1 | g02309274 |
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(1) Air inlet motor
(2) Air outlet motor (3) Air blend motor | |
The air conditioner unit contains three motor assemblies which control the position of air dampers.
When the related switch is operated from the control panel, power is supplied to terminal 1 or 2 of the motor. The direction of rotation varies according to the terminal that receives power. Each motor has a potentiometer. The amount of potentiometer resistance varies according to the speed of the motor. The control panel supplies 5 VDC to the potentiometer. The control panel detects the position of the damper by measuring the voltage difference. The control panel then stops the power supply to the motor when the designated position is detected. The designated position is set at the control panel.
Note: If power is supplied directly to the motor, do not drive the motor. The output shaft of the motor could be damaged. The winding of the motor could break.
Air inlet motor (1) is located on the air inlet end of the air conditioner unit. The air inlet motor is connected to a damper by linkage and opens or closes the damper to direct recirculated air or fresh air into the cab. The air inlet motor has a potentiometer that connects with the shaft of the motor.
The target position of the air inlet damper is determined by the setting of the air inlet select switch on the control panel. The potentiometer sends data to the control panel. The control panel will determine the direction that the shaft of the motor will rotate. When the shaft starts to rotate, data from the potentiometer, in response to the rotation angle of the shaft, is sent to the control panel. When the target position is reached, the control module will send a signal to turn the air inlet motor OFF.
Air outlet motor (2) is located at the air discharge outlet of the air conditioner unit. The air outlet motor is connected to a damper by linkage and opens or closes the damper to direct air to the selected air outlet. The air outlet motor has a potentiometer that connects with the shaft of the motor.
The target position of the air outlet damper is determined by the setting of the air outlet select switch on the control panel. The potentiometer sends data to the control panel. The control panel will determine the direction that the shaft of the motor will rotate. When the shaft starts to rotate, data from the potentiometer, in response to the rotation angle of the shaft, is sent to the control panel. When the target position is reached, the control module will send a signal to turn the air outlet motor OFF.
Air blend motor (3) is located in the center of the air conditioning unit. The air blend motor is connected to a damper by linkage and opens or closes the damper to control air temperature. The air blend motor has a potentiometer that connects with the shaft of the motor.
The target position of the air blend damper is determined by the setting of the temperature switch on the control panel. The potentiometer sends data to the control panel. The control panel will determine the direction that the shaft of the motor will rotate. When the shaft starts to rotate, data from the potentiometer, in response to the rotation angle of the shaft, is sent to the control panel. When the target position is reached, the control module will send a signal to turn the air blend motor OFF.