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
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 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. Further, the peak temperature characteristic such as the first peak of the initial permeability of the core material may be selected in the range of -40.degree.C to +5.degree.C. The core is provided with a small gap to improve lamp starting operation at high temperatures, the gap having conventional as opposed to mirror polished faces.
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 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. Thus, the lumen-per-watt efficacy of the lighting device is improved since the filament current is substantially eliminated during the lamp operation. After the initial ignition period it is preferred to use the capacitor of the parallel circuit as an intermittent commutation capacitor in the high frequency and high voltage generating oscillation circuit having an oscillation capacitor, a nonlinear inductor and a thyristor.
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 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 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:
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:
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. In a preferred embodiment, the discharge lamp lighting device includes an HF oscillating circuit for converting an LF component into an HF component and for supplying its intermittent output to the discharge lamp to reignite the discharge lamp at the initial part in each half cycle of the AC source, and to keep the lamp continuously lit.