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.

A power tool is provided including an electric universal motor. 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 higher than the operating voltage of the motor, or Direct Current (DC) power from a DC power supply having a second nominal voltage that falls approximately within the operating voltage range of the motor. The power supply interface outputs 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, and reduces a supply of power from the AC power line to a level corresponding to the operating voltage of the operating voltage range of the motor.

A power tool is provided including an electric universal motor. 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 higher than the operating voltage of the motor, or Direct Current (DC) power from a DC power supply having a second nominal voltage that falls approximately within the operating voltage range of the motor. The power supply interface outputs 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, and reduces a supply of power from the AC power line to a level corresponding to the operating voltage of the operating voltage range of the motor.

An arc-free phase control circuit for an AC motor that brings about an energy saving effect according to a load change and operates efficiently in terms of cost reduction while securing electrical stability by virtue of an overload protection function. The circuit includes a first relay, a TRIAC, a second relay, a voltage sensing unit, a current sensing unit, a speed voltage sensing unit, a zero-cross point detection unit, and a controller.

A power tool is provided including a brushless motor having a rotor and a stator. A power supply interface is arranged to selectively receive a first power input from a first power supply having a first nominal voltage and a second power input from a second power supply having a second nominal voltage, where at least the first nominal voltage does not fall within approximately the operating voltage range of the motor. A motor control circuit is provided including a power switch circuit having power switches that supply electric power from at least one of the first power input or the second power input to the motor, and a controller that controls a switching operation of the power switches to optimize the supply of electric power from the first power input at a level corresponding to the operating voltage range of the motor.

A power tool is provided including a brushless motor having a rotor and a stator. A power supply interface is arranged to selectively receive a first power input from a first power supply having a first nominal voltage and a second power input from a second power supply having a second nominal voltage, where at least the first nominal voltage does not fall within approximately the operating voltage range of the motor. A motor control circuit is provided including a power switch circuit having power switches that supply electric power from at least one of the first power input or the second power input to the motor, and a controller that controls a switching operation of the power switches to optimize the supply of electric power from the first power input at a level corresponding to the operating voltage range of the motor.

A system is disclosed comprising a DC power supply for supplying DC power to a device having a universal electric motor configured to operate on AC power. The system is configured to have a first authorization component associated with the device and second authorization component associated with the DC power supply so that DC power is supplied to device, or is continued to be supplied to the device, only when the first and second authorization components operatively engage.

A system is disclosed comprising a DC power supply for supplying DC power to a device having a universal electric motor configured to operate on AC power. The system is configured to have a first authorization component associated with the device and second authorization component associated with the DC power supply so that DC power is supplied to device, or is continued to be supplied to the device, only when the first and second authorization components operatively engage.

A cordless power tool system including (a) a multi-voltage battery pack for use with tools of different operating voltages including a housing, a first string of battery cells arranged in electrical series and disposed inside the housing, a second string of battery cells arranged in electrical series and disposed inside the 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 (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 (b) a battery pack charger configured to charge the multi-voltage battery pack.

A cordless power tool system including (a) a multi-voltage battery pack for use with tools of different operating voltages including a housing, a first string of battery cells arranged in electrical series and disposed inside the housing, a second string of battery cells arranged in electrical series and disposed inside the 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 (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 (b) a battery pack charger configured to charge the multi-voltage battery pack.