Abstract: A graphite steel available as a material for mechanical parts of industrial machines or automobiles, and more particularly, a steel wire for graphitization heat treatment and a graphite steel and methods of manufacturing the same. The graphite steel includes, in percent by weight (wt %), 0.6 to 0.9% of carbon (C), 2.0 to 2.5% of silicon (Si), 0.1 to 0.6% of manganese (Mn), 0.015% or less of phosphorus (P), 0.03% or less of sulfur (S), 0.01 to 0.05% of aluminum (Al), 0.01 to 0.02% of titanium (Ti), 0.0005 to 0.002% of boron (B), 0.003 to 0.015% of nitrogen (N), 0.005% or less of oxygen (O), and the remainder of iron (Fe) and inevitable impurities, and satisfying Equation (1) below: wherein graphite grains are distributed in a ferrite base as a microstructure and a graphitization rate is 100%, (1) ?0.003<[N]?[Ti]/3.43?[B]/0.77<0.003, wherein in Equation (1), [Ti], [N], and [B] are wt % of titanium, nitrogen, and boron, respectively.

Abstract: A vacuum cleaner is provided. The vacuum cleaner includes a motor configured to rotate at a speed of predetermined revolutions per minute (RPM) in a normal mode, a first switch configured to control a power on/off operation of the vacuum cleaner, a second switch configured to change an operation mode of the vacuum cleaner, a battery unit including a first processor configured to, based on the first switch being pressed, control a power of the vacuum cleaner to be turned on, and a second processor configured to, based on the power of the vacuum cleaner being turned on according to an operation of the first switch, control the vacuum cleaner to operate in the normal mode, and according to an operation of the second switch in the normal mode, control the vacuum cleaner to operate in a standby mode where power supplied to the motor is turned off.

Abstract: A vacuum cleaner includes a fan motor configured to generate suction, an input button configured to receive an input of a user, a first power supply circuit configured to convert alternating current (AC) power supplied from an external power source and output first direct current (DC) power, a second power supply circuit configured to store electric energy upon receiving the first DC power, and output second DC power based on the stored electric energy, a driver circuit configured to drive the fan motor upon receiving at least one of the first DC power and the second DC power, a first semiconductor switching circuit configured to control the first DC power supplied to the second power supply circuit, a second semiconductor switching circuit configured to control the first DC power and the second DC power that are supplied to the driver circuit, and a microprocessor configured to output a control signal for turning on or off the first semiconductor switching circuit and the second semiconductor switching circu

Abstract: A vacuum cleaner is provided. The vacuum cleaner includes a motor configured to rotate at a speed of predetermined revolutions per minute (RPM) in a normal mode, a first switch configured to control a power on/off operation of the vacuum cleaner, a second switch configured to change an operation mode of the vacuum cleaner, a battery unit including a first processor configured to, based on the first switch being pressed, control a power of the vacuum cleaner to be turned on, and a second processor configured to, based on the power of the vacuum cleaner being turned on according to an operation of the first switch, control the vacuum cleaner to operate in the normal mode, and according to an operation of the second switch in the normal mode, control the vacuum cleaner to operate in a standby mode where power supplied to the motor is turned off.

Abstract: A vacuum cleaner includes a fan motor configured to generate suction, an input button configured to receive an input of a user, a first power supply circuit configured to convert alternating current (AC) power supplied from an external power source and output first direct current (DC) power, a second power supply circuit configured to store electric energy upon receiving the first DC power, and output second DC power based on the stored electric energy, a driver circuit configured to drive the fan motor upon receiving at least one of the first DC power and the second DC power, a first semiconductor switching circuit configured to control the first DC power supplied to the second power supply circuit, a second semiconductor switching circuit configured to control the first DC power and the second DC power that are supplied to the driver circuit, and a microprocessor configured to output a control signal for turning on or off the first semiconductor switching circuit and the second semiconductor switching circu

Abstract: A motor driving apparatus and a refrigerator using the same is provided. The refrigerator may include a compressor, a motor, a driving unit, temperature sensing units sensing the temperatures of storage chambers and an external temperature, and a control unit selecting a driving mode of the driving unit based on the sensing result of the temperature sensing units and controlling the driving unit to drive the motor according to the selected driving mode. In a general operation mode, the control unit controls the driving unit to drive the motor in a 120 degree conduction method, and in a power-saving operation mode, the control unit controls the driving unit to drive the motor in a 90 degree conduction method. The refrigerator increases a pulse width of driving current by converting the conduction method of the motor to drive the motor at a low speed during power-saving operation of the refrigerator.

Abstract: A motor driving apparatus and a refrigerator using the same is provided. The refrigerator may include a compressor, a motor, a driving unit, temperature sensing units sensing the temperatures of storage chambers and an external temperature, and a control unit selecting a driving mode of the driving unit based on the sensing result of the temperature sensing units and controlling the driving unit to drive the motor according to the selected driving mode. In a general operation mode, the control unit controls the driving unit to drive the motor in a 120 degree conduction method, and in a power-saving operation mode, the control unit controls the driving unit to drive the motor in a 90 degree conduction method. The refrigerator increases a pulse width of driving current by converting the conduction method of the motor to drive the motor at a low speed during power-saving operation of the refrigerator.