Abstract: A brushless motor comprising a stator core having a plurality of tooth portions disposed peripherally at intervals, coils wound in a required manner on a plurality of tooth portions, an annular rotor magnet disposed in opposition to the stator core and having N poles and S poles alternately disposed, and a position detecting sensor for detecting the rotating angular position of the rotor magnet. The stator core is formed by laminating an anisotropic steel sheet in which the easily magnetizable axis of the crystal is in a specific direction.

Abstract: A method of starting a sensorless motor comprising a stator provided with three-phase stator coils to which an exciting current is supplied, and a rotor provided with a rotor magnet for obtaining a rotating torque by the electromagnetic interaction of the stator wherein a first stepping step and a second stepping step for starting the rotor at the time of starting the motor are carried out. In the early period of the second stepping step, a reverse exciting operation is carried out in which an exciting current is switched off from positive to negative or from negative to positive without including a cessation period in two-phase coils out of the three-phase stator coils.

Abstract: A starting method for starting a multiphase DC motor having a stator provided with stator coils, a rotor provided with a rotor magnet and detector for detecting revolutions of the rotor, has stepping process and acceleration process. In the stepping process, a plurality of stepping steps is performed. The accelerating process is performed after the stepping process is completed. The plurality of the stepping steps include counter-exciting operation. Each of the plurality of stepping steps is provided by a rotation detection step. The stepping process is completed and the accelerating process is performed when a rotation detector detects that the revolutions of the rotor exceeds a predetermined value.

Abstract: A driving control circuit of a sensorless motor having a stator and a rotor, used for a magnetic disk device, comprising a high-frequency stepping oscillator, stepping oscillator, a timer, a stepping timing generating circuit, a current switching logic, an output driver, and a counter electromotive force detecting circuit, wherein three-phase driving coils are connected to an output driver. For starting, a high frequency stepping step a holding step where current flow conditions are held without switching currents to the driving coils, are executed; then, currents to the driving coils are inverted to obtain a reversed excited condition; and, after performing a stepping step for starting the motor is controlled at a steady rotating speed by detecting counter electromotive forces.

Abstract: A method of starting a motor comprising a first starting step of supplying an exciting current to armature coils, a first holding step for holding the exciting current after the first starting step, a second starting step of supplying an exciting current to the armature coils after the first holding step, a second holding step of holding this exciting current after the second starting step, and a third starting step of supplying an exciting current to the armature coils after the second holding step. In this method, the frequency f.sub.1 of the first holding step is larger than the characteristic frequency F.sub.0 of the rotation system of the motor (f.sub.1 >F.sub.0) and the frequency f.sub.2 of the second holding step is smaller than the characteristic frequency F.sub.0 of the rotation system (f.sub.2 <F.sub.0).

Abstract: A DC motor having a housing, a hub member rotatably supported by the housing, a flexible printed circuit board fixedly mounted on the housing, and an IC chip mounted on the flexible printed circuit board and located facing a recess formed in the housing. The hub member has a shaft rotatably supported by a bearing within the recess. The flexible printed circuit board has a metal layer for mounting the IC chip, the metal layer being isolated from a wiring pattern formed on the printed circuit board. The wiring pattern on the flexible printed circuit board is directly connected to a connection pin connected to the motor wiring.

Abstract: A brushless polyphase DC motor is applied to a spindle motor for a disk device and has a stator generating a magnetic field in an excited state and a rotor obtaining turning force by the electromagnetic interaction with the stator. When an electrical charge current is intermittently and alternately supplied to the coil of the stator in opposite directions, for example, if electrical charge is stopped after current in the normal direction is supplied, a residual magnetic field density is generated in the stator during the stopping period. The residual magnetic flux density is employed for performing electrical charge in the reverse direction by supplying current in the reverse direction. In this case, a high torque is generated by increasing a change in the magnetic flux density.

Abstract: In a sensorless multiphase dc motor which is started by repeating a sequence of steps in order to supply the stator with a series of discrete currents for rotating the rotor in a desired direction, the start-up sequence has a step(s) of conducting a magnetizing shift action by changing the flow of current from one direction to the reverse direction or vice versa thus reducing its time consumption and also, each of the plural phase coils is energized with a high amplitude of current to produce a higher torque thus enhancing the start-up characteristics of the motor.In particular, the magnetizing shift action from one direction to the reverse direction or vice versa is conducted multiple times in each of the plural phase coils during the start-up sequence and the start-up sequence itself is repeated multiple times. As the result, the start-up characteristics of the motor will be more enhanced.

Abstract: A driving control circuit of a motor having a sensorless stator and a rotor, used for a magnetic disk device, comprising a high-frequency stepping oscillator, stepping oscillator, a timer, a stepping timing generating circuit, a current switching logic, an output driver, and a counter electromotive force detecting circuit, wherein three-phase driving coils are connected to an output driver. For starting, a holding step where current flow conditions are held without switching currents to the driving coils, are executed; then, currents to the driving coils are inverted to obtain a reversed excited condition, and, after performing a stepping step for starting, the motor is controlled at a steady rotating speed by detecting counter electromotive forces.

Abstract: A high intensity discharge (HID) lamp has an arc tube including a pair of main electrodes and at least one auxiliary electrode or probe, wherein a high frequency (HF) high voltage is applied to the probe for forming a high frequency (HF) ignition discharge for establishing a low frequency (LF) arc discharge between the main electrodes. In this ignition system, the electrodes of the arc tube are arranged so that an LF discharge path and an HF discharge path are positioned in an X- or a Y-configuration in the arc tube for causing easy lamp ignition. Also, to simplify the outer leads, it is desirable to mount the probe on one of the main electrodes by a dielectric member opposite another main electrode thereby to form a shorter gap between the probe and the other main electrodes than that between the main electrodes. The starting device of HID lamps has a high frequency-high voltage (HF-HV) generator, the output of which is applied, directly or indirectly, to the probe.

Abstract: In a discharge lamp lighting system comprising a DC or low frequency (LF) AC main source and a high frequency (HF) source, a high frequency component from the HF source and low frequency component from the main source are supplied in an overlapping manner to the discharge lamp. The HF source of the lighting device is energized by input current from the main source for producing a high frequency current. In addition, the lighting device for the discharge lamp include in combination an HF blocking circuit, an HF passing circuit and/or a matching circuit for the HF source to supply effectively a high frequency component to the discharge lamp, as well as a low frequency component from the main source.

Abstract: A discharge lamp lighting circuit system comprises a discharge lamp, an intermittent oscillation circuit, and an arrangement for controlling the energy supplied for lighting the discharge lamp with a high power factor. The intermittent oscillation circuit is energized by a low frequency a.c. power supply, i.e. a commercial alternating current power supply, for intermittently generating a high frequency high voltage in each half cycle of the alternating current of the low frequency a.c. power supply. By supplying the low frequency alternating current voltage and the intermittent high frequency high voltage to the lamp the discharge lamp is reignited in each half cycle of the a.c. of the low frequency alternating current power supply and the lit state of the discharge lamp is sustained by the low frequency alternating current voltage.

Abstract: A parallel circuit of a capacitor and a switching element is connected to a hot cathode discharge lamp lighting device using a high frequency and high voltage generating means for permitting the flow of current into the filaments of the hot cathode type discharge lamp only at the lamp starting time. The switching element of the parallel circuit is a current controlled resistance element, such as a switching semiconductor, having a break-over voltage V.sub.BO lower than the capacitor terminal voltage during the initial ignition period and higher than the capacitor terminal voltage during the reignition or operation period, whereby the filament current to the discharge lamp may be used for preheating of the filament in the initial ignition period. The filament current may be stopped or reduced by turning off of the switching element by raising the terminal voltage of the capacitor in the reignition period during normal operation.

Abstract: A high frequency and high voltage generating circuit for a discharge lamp lighting device controls its initial output at the starting time of a discharge lamp to prevent applying a high voltage to the discharge lamp in the "cold cathode" state. The circuit comprises in combination an oscillation circuit having an oscillation capacitor, a non-linear inductor and a thyristor, and an initial output limiter for delaying the output supply until the lamp filament is sufficiently preheated for preventing sputtering and for extending the operational life of the discharge lamp. The output control is formed as a bias circuit for the nonlinear inductor and includes a thermistor with a negative or a positive temperature coefficient.

Abstract: A discharge lamp is ignited in every half cycle in its operating system including a discharge lamp operating circuit provided with a low frequency alternating current power source, a single winding type current limiter. The discharge lamp is connected to the power source through the current limiter and a series circuit including a high voltage output generator is connected in parallel to the discharge lamp. The high voltage output generator operates during the lamp operation for reigniting the discharge lamp. The voltage of the low frequency alternating current power source is set to less than the required reignition voltage of the discharge lamp during its operation, whereby the lamp current stabilizer size is minimized. Further, a filament preheating circuit is arranged to use current derived from the high voltage generator. The filament preheating circuit is combined with this operating circuit and so is a time delay for assuring a stable operation.

Abstract: The present discharge lamp system comprises two or more serially connected discharge lamps connected across a pair of power input supply terminals through a ballast circuit and two or more serially connected semiconductor starter circuits. The starters are connected in parallel with their respective discharge lamps and have inherent breakdown voltages, whereby the total value of the breakdown voltages for each starter is higher than the source voltage at the power supply terminals. The system further comprises voltage dividing circuit elements enabling the conduction of one of the starters before the conduction of the other starter or starters in response to the source voltage, whereby the starters operate sequentially. At least one of the starters employs a backswing booster including a series circuit of a nonlinear inductor and a switching semiconductor and a capacitor connected in parallel with the series circuit to provide a sufficient starting voltage for the associated discharge lamp.

Abstract: A discharge lamp lighting device combines one or more discharge lamps and a backswing booster including essentially a power source circuit having a power source connected in series with a ballast and a high voltage generating circuit having an oscillation capacitor and a series circuit of a nonlinear inductor and a switching semiconductor. The supply voltage for the discharge lamp from the power source circuit is established to the extent permissible by the lower limit for sustaining an arc discharge of the lamp so that the terminal voltage of the ballast in the lamp operation is maintained as low as possible. The preferred backswing booster is of small size and an impedance circuit having a capacitor either with or without a bias coil is added to the high voltage generating circuit to produce a momentary high voltage.

Abstract: It is the purpose of the present discharge lamp lighting system to provide reignition energy to a discharge lamp in each half cycle of the a.c. power source. The discharge lamp is connected to a conventional a.c. power source through ballast means and an oscillation booster circuit, which provides an intermittent oscillation output for the reignition operation of the discharge lamp. The operation period of the intermittent oscillation output is so controlled that the reignition operation period is included in each half cycle of the discharge lamp current. The lamp voltage and source voltage are established to agree as much as possible with each other for minimizing the terminal voltage of the ballast means, whereby a compact and economical device with a small inductance ballast means is achieved.

Abstract: A discharge lamp lighting apparatus includes three oscillation circuits. The first comprises a linear inductor and a capacitor connected in series to a power source. The second oscillation circuit is connected across the capacitor and includes a bounce or backswing booster inductor and a voltage responsive switching element connected in series. The third oscillation circuit comprises the bounce inductor and its distributed capacity. The bounce booster inductor has a magnetic core with a shape and of a material providing an abrupt saturation characteristic. The core factor K of the core is small and may have a ratio of the cross sections of the wound to the unwound parts thereof of less than one half. Alternatively, the ratio of the wound part of the core to the unwound part thereof is less than one fourth and a conventional core material may be employed for the core.