Work machine

A work machine, comprising:

• a motor having a plurality of windings;
• a drive unit driving the motor;
• a connection switching unit configured to be capable of switching between a high rotational speed connection state in which the plurality of windings are connected to each other to have a high rotational speed characteristic, and a high torque connection state in which the plurality of windings are connected to each other to have a high torque characteristic;
• an operation unit operating start and stop of the motor;
• and
• a controller controlling the drive unit and the connection switching unit,
• wherein the controller is capable of executing connection switching control for switching from the high rotational speed connection state to the high torque connection state, and is configured to start the connection switching control in a state where a rotational speed of the motor is higher than an idling rotational speed of the high torque connection state, and
• wherein the controller is configured to stop driving of the motor when executing the connection switching control, and resume driving of the motor immediately after executing the connection switching control.

A work machine, comprising:

• a motor having a plurality of windings;
• a drive unit driving the motor;
• a connection switching unit configured to be capable of switching from one connection state to the other connection state of a high rotational speed connection state in which the plurality of windings are connected to each other to have a high rotational speed characteristic, and a high torque connection state in which the plurality of windings are connected to each other to have a high torque characteristic;
• an operation unit operating start and stop of the motor;
• and
• a controller controlling the drive unit and the connection switching unit,
• wherein the controller is capable of executing connection switching control for switching from the one connection state to the other connection state, and is configured to switch the drive unit to a drive stop state in which supply of drive power to the motor is stopped, and to switch the connection switching unit from the one connection state to a connection terminated state in which the plurality of windings are cut off from each other, in the connection switching control, and
• wherein the controller is configured to stop driving of the motor when executing the connection switching control, and resume driving of the motor immediately after executing the connection switching control.

A work machine, comprising:

• a motor having a plurality of windings;
• a drive unit driving the motor;
• a connection switching unit configured to be capable of switching between a high rotational speed connection state in which the plurality of windings are connected to each other to have a high rotational speed characteristic, and a high torque connection state in which the plurality of windings are connected to each other to have a high torque characteristic;
• an operation unit operating start and stop of the motor;
• and
• a controller controlling the drive unit and the connection switching unit,
• wherein the controller is capable of executing connection switching control for switching from the high rotational speed connection state to the high torque connection state, and is configured to start the connection switching control in a state where a rotational speed of the motor is higher than an idling rotational speed of the high torque connection state, and
• wherein the controller is configured to
• switch the connection state to the high torque connection state when the work load increases and becomes equal to or greater than a first winding switching threshold value while setting the connection state as the high rotational speed connection state, and
• switch the connection state to the high rotational speed connection state when the work load decreases and becomes equal to or smaller than a second winding switching threshold value while setting the connection state as the high torque connection state, and the first winding switching threshold value is greater than the second winding switching threshold value.