Abstract: An electrical method for centering telehandler rear wheels preferably includes an electronic control module (ECM), a rear steering cylinder, a pair of rear centering valves, a front steering cylinder, a steer mode valve, at least one steering position sensor, a steering control unit and a mode selection switch. The front and rear steering cylinders are connected to the steer mode valve. The steering control unit directs hydraulic fluid from a hydraulic pump to flow into the front and rear steering cylinders to turn the wheels. A 2W steering mode requires that the rear wheels be straight before going from a 4W steering mode into the 2W steering mode. The ECM monitors a position of the rear wheels through the at least one steering position sensor. If the wheels are not straight, the ECM will open a centering valve to straighten the rear wheels, before going into the 2W steering mode.

Abstract: An electrical method for centering telehandler rear wheels preferably includes an electronic control module (ECM), a rear steering cylinder, a pair of rear centering valves, a front steering cylinder, a steer mode valve, at least one steering position sensor, a steering control unit and a mode selection switch. The front and rear steering cylinders are connected to the steer mode valve. The steering control unit directs hydraulic fluid from a hydraulic pump to flow into the front and rear steering cylinders to turn the wheels. A 2W steering mode requires that the rear wheels be straight before going from a 4W steering mode into the 2W steering mode. The ECM monitors a position of the rear wheels through the at least one steering position sensor. If the wheels are not straight, the ECM will open a centering valve to straighten the rear wheels, before going into the 2W steering mode.

Abstract: A hydraulic lockout lever failure detection system preferably includes a first analog sensor, a second analog sensor, at least one electronic control module (ECU) and a solenoid valve. The voltage output level of the first and second analog sensors is monitored by the ECU. The solenoid valve controls the flow of hydraulic fluid to operate an excavator or other equipment. The operation of the solenoid valve is controlled by the ECU. However, a second ECU may be used to control the operation of the solenoid valve. A hydraulic lockout lever causes the first and second analog sensors to output either a low voltage to indicate a closed position, or to indicate an open position to the ECU. If the first and second analog sensors output a voltage that is above a low set value or above a high set value, a fault is detected.

Abstract: A hydraulic lockout lever failure detection system preferably includes a first analog sensor, a second analog sensor, at least one electronic control module (ECU) and a solenoid valve. The voltage output level of the first and second analog sensors is monitored by the ECU. The solenoid valve controls the flow of hydraulic fluid to operate an excavator or other equipment. The operation of the solenoid valve is controlled by the ECU. However, a second ECU may be used to control the operation of the solenoid valve. A hydraulic lockout lever causes the first and second analog sensors to output either a low voltage to indicate a closed position, or to indicate an open position to the ECU. If the first and second analog sensors output a voltage that is above a low set value or above a high set value, a fault is detected.

Abstract: A method for controlling the starting, stopping and operation of an AC motor is provided. Each winding of the AC motor is interconnected to an AC source by a thyristor switch and a bypass contactor for providing voltage and current to the AC motor. The method includes a steps of sequently firing a pair of tyristor switches to bring the AC motor to full operating speed. Once at operating speed, the bypass contactors are closed. Upon detection of a voltage drop across a thyristor switch, the thyristor switch is fired immediately to transfer motor current from the bypass contactor to the thyristor switch in order to maintain voltage and current to the AC motor.