An excavator comprising: an electric motor having a commercial power supply and a battery as the drive power sources therefor; and a hydraulic actuator having a hydraulic pump driven by the electric motor, as the hydraulic source therefor. The excavator has: a first power supply mode in which the electric motor is driven while the battery is being charged by the commercial power supply; and a second power supply mode in which the electric motor is driven only by the battery. A power supply cable for supplying power from the commercial power supply is connected to a power supply port and, if the electric motor has stopped operating, the excavator moves from the second power supply mode to the first power supply mode.

An excavator comprising: a battery; an electric motor having the battery as the drive power source therefor; a hydraulic actuator having a hydraulic pump driven by the electric motor as the oil pressure source therefor; a cut-off lever that limits operation of the hydraulic actuator by cutting off pilot pressure that operates the hydraulic actuator; an electric cooling pump that circulates cooling water through a cooling water path for cooling electrical equipment including the battery and the electric motor; an electric cooling fan that blows cooling air on to a radiator provided on the cooling water path; and a system controller that, if the cut-off lever is rotated upwards and a command to limit the hydraulic actuator is received, stops the electric motor, the cooling pump, and the cooling fan.

Systems and methods are disclosed for managing task assignments for a plurality of work machines at a site. An assignment engine may: receive first state data for a work machine including historical data, operating condition, and location data, and second state data for the site including characteristic data for materials and a plurality of available tasks; predict performance data and energy consumption data of the work machine for a task; select a task for the work machine by inputting first state data and second state data into a trained reinforcement-learning model, wherein: the model has been trained to learn an assignment policy that optimizes a reward function such that the learned policy selects a task for at least one work machine from the plurality of tasks available at the site; and cause the at least one work machine to be operated according to the at least one task assignment.

A drive for a work machine includes a computer configured to control a first electric motor for driving vehicle wheels and a second electric motor for driving a work attachment. The computer is configured to process signals which correspond to control of a movement of a lifting mechanism of the work attachment or a bucket of the work attachment. The computer is further configured to process a signal which corresponds to a position of an accelerator pedal. The first electric motor and the second electric motor are configured to be controlled separately from each another, and control of the second electric motor takes place according to the control of the movement of the work attachment.

A drive for a machine includes a computer configured to control a first electric motor for driving vehicle wheels and a second electric motor for driving a work attachment. The second electric motor is configured to drive at least one hydraulic pump with an adjustable stroke volume. A sensor is configured to detect the stroke volume of the pump. The computer processes the stroke volume to control the second electric motor.

A management server (52) receives a maximum value and a minimum value of the respective voltages (cell voltages) in a plurality of battery cells (19A, 19A) configuring an electricity storage device (19) of a hydraulic excavator (1) from the hydraulic excavator (1), and stores the maximum value and the minimum value in a storage device (52A). Discharge characteristics of the electricity storage device (19) are stored in the storage device (52A) in the management server (52). A battery state estimation calculating unit (52D) in the management server (52) calculates an estimation maximum value and an estimation minimum value of cell voltages in the present or in the future by adding the discharge characteristics stored in the storage device (52A) to the latest maximum value and the latest minimum value of the cell voltages stored in the storage device (52A). A management information producing unit (52C) outputs information based upon the estimation maximum value and the estimation minimum value of the cell voltages calculated in the battery state estimation calculating unit (52D).

An electric drive work machine may include a body frame, a first electric power storage device mounted on the body frame, a second electric power storage device mounted on the body frame, and a junction box mounted on the body frame. The junction box may be operatively connected to the first electric power storage device by a first electric connection having a first inductance, and operatively connected to the second electric power storage device by a second electric connection having a second inductance. The first inductance may be equal to the second inductance such that power source charging power from the junction box is distributed equally to the first electric power storage device and the second electric power storage device, and power source output power to the junction box is drawn equally from the first electric power storage device and the second electric power storage device.

An electric drive work machine may include a body frame, a first electric power storage device mounted on the body frame, a second electric power storage device mounted on the body frame, and a junction box mounted on the body frame. The junction box may be operatively connected to the first electric power storage device by a first electric connection having a first inductance, and operatively connected to the second electric power storage device by a second electric connection having a second inductance. The first inductance may be equal to the second inductance such that power source charging power from the junction box is distributed equally to the first electric power storage device and the second electric power storage device, and power source output power to the junction box is drawn equally from the first electric power storage device and the second electric power storage device.

A hybrid construction machine includes: a motor generator system connected to an internal combustion engine and performing a motor generator operation; an electric power accumulation system connected to the motor generator system; a load drive system connected to the electric power accumulation system and being driven electrically; an abnormality detection part equipped to the motor generator system, the electric power accumulation system and the load drive system; and a main control part determining whether an abnormality has occurred based on a detection value of the abnormality detection part. When the abnormality determination part determines that an abnormality has occurred, the main control part stops a drive of a drive system in which the abnormality is detected in the load drive system.

A plus-side main connection line (17) connects electrical equipment (11), (12) to a plus terminal (16A) of a battery (16). A plus-side isolating switch (18) is provided in the plus-side main connection line (17) to connect or disconnect the electrical equipment (11), (12) and or from the plus terminal (16A) of the battery (16). A plus-side auxiliary connection line (20) connects a communication terminal (15) to the plus terminal (16A) of the battery (16) in a position upstream of the plus-side isolating switch (18). A minus-side main connection line (22) connects a minus terminal (16B) of the battery (16) to ground. A minus-side isolating switch (23) is provided in the minus-side main connection line (22) to connect or disconnect the minus terminal (16B) of the battery (16) and or from the ground.