A power adapter for use with a power tool having an electric motor, and configured to supply electric power from an alternating current power supply to the power tool, is provided. The adapter includes a housing and an auxiliary capacitor circuit housed within the housing. The auxiliary capacitor circuit includes an auxiliary capacitor, a switch in series with the auxiliary capacitor, and a switch control circuit. A state of the switch creates either a charging path for the auxiliary capacitor or both the charging path and a discharging path for the auxiliary capacitor, and the switch control circuit is configured to detect voltage associated with the power supply or the power tool and to control state of the switch in accordance with magnitude of the detected voltage.

A power adapter for use with a power tool having an electric motor, and configured to supply electric power from an alternating current power supply to the power tool, is provided. The adapter includes a housing and an auxiliary capacitor circuit housed within the housing. The auxiliary capacitor circuit includes an auxiliary capacitor, a switch in series with the auxiliary capacitor, and a switch control circuit. A state of the switch creates either a charging path for the auxiliary capacitor or both the charging path and a discharging path for the auxiliary capacitor, and the switch control circuit is configured to detect voltage associated with the power supply or the power tool and to control state of the switch in accordance with magnitude of the detected voltage.

A method for operating a universal motor, comprising the following steps: establishing a synthetic variable from at least two physical operating parameters of the universal motor; and operating the universal motor using operating parameters of this type so that the synthetic variable remains at a substantially constant level or at least does not exceed a defined permissible upper limit.

A method for operating a universal motor, comprising the following steps: establishing a synthetic variable from at least two physical operating parameters of the universal motor; and operating the universal motor using operating parameters of this type so that the synthetic variable remains at a substantially constant level or at least does not exceed a defined permissible upper limit.

An upright vacuum cleaner includes a cleaning head having a suction opening defined along a bottom thereof, a handle assembly connected to the cleaning head, a motor, and a blower connected to the motor and operable to generate suction through the suction opening upon operation of the motor. The vacuum cleaner further includes an electrical connection interface selectively connectable to a direct current (DC) power source and an alternating current (AC) power source. The electrical connection interface is electrically connectable to the motor via an electrical path such that an AC current is supplied to the motor when the AC power source is connected to the electrical connection interface, and a DC current is supplied to the motor when the DC power source is connected to the electrical connection interface.

A system comprising a multi-voltage battery pack for use with tools of different operating voltages, including a housing and a power tool interface shaped and configured to interchangeably (1) mechanically and electrically couple with a first battery pack interface of a first power tool that is configured to operate at a first operating voltage and that was on sale prior to May 18, 2014 and, and (2) mechanically and electrically couple with a second battery pack interface of a second power tool that is configured to operate at a second operating voltage and that was not on sale prior to May 18, 2014.

A system comprising a multi-voltage battery pack for use with tools of different operating voltages, including a housing and a power tool interface shaped and configured to interchangeably (1) mechanically and electrically couple with a first battery pack interface of a first power tool that is configured to operate at a first operating voltage and that was on sale prior to May 18, 2014 and, and (2) mechanically and electrically couple with a second battery pack interface of a second power tool that is configured to operate at a second operating voltage and that was not on sale prior to May 18, 2014.

An electric working machine comprises a motor, a switch, a drive device, a brake device, and a failure determiner. The switch is configured for operation by a user, has an on-state and an off-state. The drive device is configured to drive the motor in response to the switch being placed in the on-state. The brake device is configured to control deceleration of the motor to a stopped state in response to the switch being placed in the off-state. The failure determiner is configured to monitor deceleration of the motor during controlled deceleration and to determine whether the brake device has failed based on the monitored deceleration.

An electric working machine comprises a motor, a switch, a drive device, a brake device, and a failure determiner. The switch is configured for operation by a user, has an on-state and an off-state. The drive device is configured to drive the motor in response to the switch being placed in the on-state. The brake device is configured to control deceleration of the motor to a stopped state in response to the switch being placed in the off-state. The failure determiner is configured to monitor deceleration of the motor during controlled deceleration and to determine whether the brake device has failed based on the monitored deceleration.

A power tool is provided including an electric universal motor configured to operate within an operating voltage range of approximately 90V to 132V. A power supply interface is arranged to receive at least one of Alternating Current (AC) power from an AC power supply having a first nominal voltage or Direct Current (DC) power from a DC power supply having a second nominal voltage, where the first and second nominal voltages fall approximately within the operating voltage range of the motor. The power supply interface is configured to output the AC power via an AC power line and the DC power via a DC power line. A motor control circuit supplies electric power from one of the AC power line or the DC power line via a common node to the motor such that the motor brushes are electrically coupled to one of the AC or DC power supplies.