A cart may include a driving wheel, a motor configured to rotate the driving wheel, a motor drive circuit configured to drive the motor, a motor brake circuit configured to electrically brake the motor, a control device configured to control the motor via the motor drive circuit and the motor brake circuit so that a travelling speed of the cart becomes equal to or lower than an upper limit travelling speed, and a temperature sensor configured to detect a temperature of the motor brake circuit. The control device may be configured to change the upper limit travelling speed to a second upper limit travelling speed lower than the first upper limit travelling speed when the upper limit travelling speed is a first upper limit travelling speed and the temperature detected by the temperature sensor exceeds a first predetermined temperature.

A cart may include a driving wheel, a motor configured to rotate the driving wheel, a motor drive circuit configured to drive the motor, a motor brake circuit configured to electrically brake the motor, a control device configured to control the motor via the motor drive circuit and the motor brake circuit so that a travelling speed of the cart becomes equal to or lower than an upper limit travelling speed, and a temperature sensor configured to detect a temperature of the motor brake circuit. The control device may be configured to change the upper limit travelling speed to a second upper limit travelling speed lower than the first upper limit travelling speed when the upper limit travelling speed is a first upper limit travelling speed and the temperature detected by the temperature sensor exceeds a first predetermined temperature.

A robot (100) includes a resistance circuit (60) configured or programmed to perform a control to reduce a braking force of a dynamic brake by changing a resistance value of a resistance component (63) with respect to a power supply path (61) when motors (30) are stopped at an abnormal stop.

A robot (100) includes a resistance circuit (60) configured or programmed to perform a control to reduce a braking force of a dynamic brake by changing a resistance value of a resistance component (63) with respect to a power supply path (61) when motors (30) are stopped at an abnormal stop.

Braking a power tool motor based on a phase voltage of the motor. The power tool includes a motor and a power source providing operating power to the motor. A power switching network is between the power source and the motor to drive the motor. An actuator is operable to provide an input. An electronic controller is connected to the actuator and the power switching network. The electronic controller is configured to receive an indication related to initiating braking of the motor, control the power switching network to allow the motor to coast, monitor a phase voltage of the motor, determine whether the phase voltage of the motor is equal to or less than a phase voltage threshold, and control, in response to the phase voltage of the motor being equal to or less than the phase voltage threshold, the power switching network to brake the motor.

Braking a power tool motor based on a phase voltage of the motor. The power tool includes a motor and a power source providing operating power to the motor. A power switching network is between the power source and the motor to drive the motor. An actuator is operable to provide an input. An electronic controller is connected to the actuator and the power switching network. The electronic controller is configured to receive an indication related to initiating braking of the motor, control the power switching network to allow the motor to coast, monitor a phase voltage of the motor, determine whether the phase voltage of the motor is equal to or less than a phase voltage threshold, and control, in response to the phase voltage of the motor being equal to or less than the phase voltage threshold, the power switching network to brake the motor.

The present disclosure relates to security mechanisms for electric motors and associated systems. For example, the present technology includes a powertrain assembly having (1) a motor having multiple sets of coils; (2) a drive circuitry electrically coupled to the multiple sets of coils; and (3) a security unit electrically coupled to the drive circuitry and the multiple sets of coils. The security unit is configured to short-circuit at least one set of the multiple sets of coils responsive to a signal from a controller. The signal indicates that the motor is, or has been, turned off.

The present disclosure relates to security mechanisms for electric motors and associated systems. For example, the present technology includes a powertrain assembly having (1) a motor having multiple sets of coils; (2) a drive circuitry electrically coupled to the multiple sets of coils; and (3) a security unit electrically coupled to the drive circuitry and the multiple sets of coils. The security unit is configured to short-circuit at least one set of the multiple sets of coils responsive to a signal from a controller. The signal indicates that the motor is, or has been, turned off.

A robot system includes a motor provided at a joint, a regenerative resistor that consumes a back electromotive force generated by rotation of the motor as heat, and a controller configured or programmed to predict a life of the regenerative resistor based on a period of time during which the regenerative resistor is consuming heat.

A method for dissipating power of an automotive electric drive system that includes a traction battery, and an inverter, wherein the inverter includes a DC bus between, and a dissipation circuit between the traction battery and DC bus, wherein the dissipation circuit includes a plurality of resistors connected in series between positive and negative terminals of the DC bus and a dissipation resistor and switch connected in series between the positive and negative terminals, the method includes responsive to a voltage across one of the plurality of resistors being less than a threshold value, deactivating the switch to prevent current flow from the positive terminal to the negative terminal through the dissipation resistor, and responsive to the voltage exceeding the threshold value, activating the switch to permit current flow from the positive terminal to the negative terminal through the dissipation resistor.