Abstract: A power tool including a battery pack interface configured to receive a removable and rechargeable battery pack, a motor including a rotor and a stator, the rotor operable to rotate relative to the stator, and a switching module that includes a plurality of switching devices connected between the battery pack interface and the motor. The power tool further includes a controller including a processor and a memory. The controller is configured to receive a signal from an external device, control the switching module to provide a high frequency current signal from battery pack to the motor in response to receiving the signal, the motor configured to emit an audible sound in response to the high frequency current signal, and control the switching module to stop providing the high frequency current signal to the motor.

Abstract: The present invention relates to a permanent magnet electrical machine, and more particularly, to a permanent magnet electrical machine for reducing a detent force, the machine being capable of reducing a detent force by arranging a plurality of movers having the same teeth at predetermined intervals. In addition, according to the present invention, the permanent magnet electrical machine comprising a stator and a plurality of movers configured to perform linear motion, curvilinear motion, or rotary motion with respect to the stator is provided.

Abstract: The present invention relates to a permanent magnet electrical machine, and more particularly, to a permanent magnet electrical machine for reducing a detent force, the machine being capable of reducing a detent force by arranging a plurality of movers having the same teeth at predetermined intervals. In addition, according to the present invention, the permanent magnet electrical machine comprising a stator and a plurality of movers configured to perform linear motion, curvilinear motion, or rotary motion with respect to the stator is provided.

Abstract: There is provided an electric machine, which is configured such that magnetic poles provided on a stator and a mover or rotor of the electric machine have an asymmetric shape, thus being capable of reducing a torque ripple.

Abstract: The present invention relates to a doubly salient permanent magnet electric machine that has a winding structure in which series-connected windings are included in the phase windings of a mover, and that has a stator implemented as an iron core having a plurality of permanent magnets and a plurality of stator salient poles neighboring the permanent magnets, thus reducing the number of permanent magnets by half. An electric machine is configured such that a mover moves while facing a stator and includes an N (a number of power phases) multiple number of teeth and phase windings wound around the teeth, and one or more pairs of phase windings of the mover mutually having a phase difference of 180° are connected in series, and the stator includes permanent magnets in depressions between individual stator salient poles of an iron core in which the stator salient poles are formed.

Abstract: Disclosed herein is a linear, curved or rotary electric machine. The electric machine includes first and second movers which are adjacent to each other and have a phase angle difference of 60° therebetween. The first mover includes phases U, V and W and the second mover includes phases /U, /V and /W. The electric machine of the present invention can reduce pulsations of thrust caused by end effect. In particular, in the case where the stator includes permanent magnets having the same poles and salient poles which alternate with the permanent magnets, the number of permanent magnets used can be reduced to half of that of a conventional linear electric machine.

Abstract: There is provided an electric machine, which is configured such that magnetic poles provided on a stator and a mover or rotor of the electric machine have an asymmetric shape, thus being capable of reducing a torque ripple.

Abstract: Disclosed herein is a linear, curved or rotary electric machine. The electric machine includes first and second movers which are adjacent to each other and have a phase angle difference of 60° therebetween. The first mover includes phases U, V and W and the second mover includes phases /U, /V and /W. The electric machine of the present invention can reduce pulsations of thrust caused by end effect. In particular, in the case where the stator includes permanent magnets having the same poles and salient poles which alternate with the permanent magnets, the number of permanent magnets used can be reduced to half of that of a conventional linear electric machine.

Abstract: Disclosed herein is a linear, curved or rotary electric machine. The electric machine includes first and second movers which are adjacent to each other and have a phase angle difference of 60° therebetween. The first mover includes phases U, V and W and the second mover includes phases /U, /V and /W. The electric machine of the present invention can reduce pulsations of thrust caused by end effect. In particular, in the case where the stator includes permanent magnets having the same poles and salient poles which alternate with the permanent magnets, the number of permanent magnets used can be reduced to half of that of a conventional linear electric machine.

Abstract: Disclosed herein is a structure for linear and rotary electric machines. The present invention provides a modular mover structure which includes coils that have an electrical phase difference of 180°, so that the path of magnetic flux is shortened, thus reducing the size of the machine and mitigating the back-EMF unbalance. The modular mover structure can be modified into various shapes. For example, when a skew structure is applied to a mover or stator iron core, the force ripples in an electric machine can be reduced. In addition, when a hinge structure is applied to a modular mover iron core, the mover can move in a linear and curved manner. The structure of the present invention can be applied to a rotary electric machine. In this case, because the number of poles is easily increased, a low speed high torque direct drive type rotary electric machine is realized.

Abstract: The present invention relates to a doubly salient permanent magnet electric machine that has a winding structure in which series-connected windings are included in the phase windings of a mover, and that has a stator implemented as an iron core having a plurality of permanent magnets and a plurality of stator salient poles neighboring the permanent magnets, thus reducing the number of permanent magnets by half. An electric machine is configured such that a mover moves while facing a stator and includes an N (a number of power phases) multiple number of teeth and phase windings wound around the teeth, and one or more pairs of phase windings of the mover mutually having a phase difference of 180° are connected in series, and the stator includes permanent magnets in depressions between individual stator salient poles of an iron core in which the stator salient poles are formed.

Abstract: Disclosed herein is an inner rotor type permanent magnet excited transverse flux motor, in which a laminated structure in an axial direction or in a radial shape is applied to a stator iron core so as to employ a small amount of permanent magnets compared with a conventional outer rotor type permanent magnet excited transverse flux motor, thus providing high output power, increasing the efficiency of power generation, and reducing noise and vibration.

Abstract: Disclosed herein is to a flux reversal motor. The flux reversal motor includes a mover, and a plurality of permanent magnets. The mover moves linearly relative to a stator. A plurality of permanent magnets, having identical polarities, is provided in the end of each mover tooth. The permanent magnets are arranged on the left and right sides of a protrusion of the end of the mover tooth. Thus low noise/low vibration, high speeds, high precision, and high thrust motion can be realized.

Abstract: Disclosed herein is a linear, curved or rotary electric machine. The electric machine includes first and second movers which are adjacent to each other and have a phase angle difference of 60° therebetween. The first mover includes phases U, V and W and the second mover includes phases /U, /V and /W. The electric machine of the present invention can reduce pulsations of thrust caused by end effect. In particular, in the case where the stator includes permanent magnets having the same poles and salient poles which alternate with the permanent magnets, the number of permanent magnets used can be reduced to half of that of a conventional linear electric machine.

Abstract: Disclosed herein is a structure for linear and rotary electric machines. The present invention provides a modular mover structure which includes coils that have an electrical phase difference of 180°, so that the path of magnetic flux is shortened, thus reducing the size of the machine and mitigating the back-EMF unbalance. Furthermore, the modular mover structure can be modified into various shapes. For example, when a skew structure is applied to a mover or stator iron core, the force ripples in an electric machine can be reduced. In addition, when a hinge structure is applied to a modular mover iron core, the mover can move in a linear and curved manner. Moreover, the structure of the present invention can be applied to a rotary electric machine. In this case, because the number of poles can be easily increased, a low speed high torque direct drive type rotary electric machine can be realized.

Abstract: Disclosed herein is to a flux reversal motor. The flux reversal motor includes a mover, and a plurality of permanent magnets. The mover moves linearly relative to a stator. A plurality of permanent magnets, having identical polarities, is provided in the end of each mover tooth. The permanent magnets are arranged on the left and right sides of a protrusion of the end of the mover tooth. Thus low noise/low vibration, high speeds, high precision, and high thrust motion can be realized.

Abstract: Disclosed herein is a permanent magnet excited transverse flux linear motor with a normal force compensation structure in which a stator is inserted in the middle of leg portions of a mover so as to compensate normal forces generated between the mover and the stator, thus reducing noise and vibration.

Abstract: Disclosed herein is an inner rotor type permanent magnet excited transverse flux motor, in which a laminated structure in an axial direction or in a radial shape is applied to a stator iron core so as to employ a small amount of permanent magnets compared with a conventional outer rotor type permanent magnet excited transverse flux motor, thus providing high output power, increasing the efficiency of power generation, and reducing noise and vibration.

Abstract: Disclosed herein is a permanent magnet excited transverse flux linear motor with a normal force compensation structure in which a stator is inserted in the middle of leg portions of a mover so as to compensate normal forces generated between the mover and the stator, thus reducing noise and vibration.