摘要:
A chair includes a seat portion 1(1B), a seat support 2(2B) supporting the seat portion 1, a rear seat support 3(3B) extending rearwardly upwardly relative to the seat support 2(2B), and a slide mechanism X1 (moving mechanism XB) for causing the seat portion 1(1B) to slide back and forth relative to the seat support 2 (2B). The chair is provided with a locking mechanism 100C for locking the seat portion 6C at a desired position in the fore-and-aft direction selectively, and a lever 110C for operating the locking mechanism 100C, the lever 110C being located at a position allowing the lever 110C to move together with the seat portion 6C in the fore-and-aft direction.
摘要:
A chair 1 allowing a person sitting thereon to move a part of the person's body above the waist which corresponds to the backrest of the chair is provided having a backrest portion located behind a seat portion, the backrest portion being divided into backrest upper frames 55 and backrest lower frames 50, wherein a first state which allows the whole backrest frame 5 to incline rearwardly and a second state which allows the backrest upper frames 55 to incline rearwardly relative to the backrest lower frames 50 are assumed, the first state and the second state being switchable to each other.
摘要:
It is an object of the invention to provide a current sensor apparatus that reduces measurement errors resulting from variations in a position of a current path passing through the space inside a magnetic yoke. The current sensor apparatus comprises a ring-shaped magnetic yoke (2) surrounding a current path (1), part of the yoke having a gap (3), and a magnetic sensor element (4) placed in the gap (3) of the magnetic yoke (2). The magnetic sensor element (4) detects a magnetic field in the gap (3) generated by a current flowing through the current path (1) to measure the current flowing through the current path (1). The current sensor apparatus further comprises a magnetic field interrupter (5), placed between the current path (1) and the gap (3), for interrupting a magnetic field corresponding to a magnetic flux generated by the current passing through the current path (1) and not passing through the magnetic yoke (2), so that the magnetic field would not reach the magnetic sensor element (4).
摘要:
A switching circuit for a power conversion apparatus capable of reducing conduction loss to provide a higher efficiency, and achieving downsizing and weight-reduction and higher driving frequency based on the improved efficiency is disclosed. A driving transistor is connected to a switching main transistor to supply a driving power for ON-OFF driving thereto, and an auxiliary power source composed of a current transformer is provided between the main transistor and the driving transistor. An auxiliary transistor having a lower switching loss than that of the main transistor is connected in parallel with the main transistor to form a main switch in combination with the main transistor. A current-driven type transistor serves as the main transistor, and voltage-driven type transistors serve as both of the driving transistor and the auxiliary transistor. The auxiliary transistor is adapted to be driven at a higher speed than that of the main transistor when the main transistor is turned on, and adapted to be driven at a lower speed than that of the main transistor when the main transistor is turned off.
摘要:
This PWM inverter apparatus includes a first and second current control type semiconductor switching elements connected in series which are connected in parallel to a DC power supply. An output is generated by alternately switching the first and second semiconductor switching elements. Resistive semiconductor switching elements having a higher switching speed than the first and second semiconductor switching elements and a resistance-to-current characteristics producing a voltage drop are respectively connected in parallel to respective the first and second semiconductor switching elements. In a half cycle of an alternating output current, while the output current is higher than a predetermined rate with respect to a peak current, a switching timing is controlled to produce a switching control signal to the resistive semiconductor switching elements ahead of a switching control signal to the first and second semiconductor switching elements, and to terminate the switching control signal to the resistive semiconductor switching elements at a time when a predetermined period passes after the switching control signal given to the first and second semiconductor switching elements has been terminated. In the half cycle of the alternating output current, while the output current is lower than the predetermined rate with respect to the peak current, the switching timing is controlled to generate the output by the switching operation only of the resistive semiconductor switching elements.
摘要:
The present invention discloses a power conversion apparatus comprising a control circuit for generating a switching signal at the timing allowing soft-switching to be achieved, and free from any occurrence of ripple. The power conversion apparatus includes a first main switch (Q1) and a second main switch (Q2) which are connected in series with each other. One of the ends of the first main switch is connected with the positive side of a DC power supply, and one of the ends of the second main switch is connected to the negative side of the DC power supply. A diode (D1, D2) is connected in parallel with each of the main switches so as to become reverse biased with respect to the DC power supply. A main-switch snubber capacitor (C1, C2) is connected in parallel with each of the main switches. A load is connected with the junction between the pair of main switches, and the main switches are controllably switched according a switching signal from a control circuit to generate an output. A first auxiliary resonant circuit including serial-connected first and second auxiliary switches (Q3, Q4, Q5, Q6) and a resonant inductor (L1) connected in series with the second auxiliary switch is connected with each of the positive side of the DC power supply and the junction between the two main switches. A diode is connected to each of the first and second auxiliary switches so as to become reverse biased with respect to the DC power supply. The control circuit provides a turn-on signal to the first and second auxiliary switches according to a voltage signal as an input representing the voltage across each of the main switches and auxiliary switches from voltage detecting means before a turn-on signal as the switching signal is provided to the first main switch.
摘要:
In a power conversion apparatus using a semiconductor switching element, a collector-emitter voltage detecting device is provided to detect the collector-emitter voltage in the semiconductor switching element in the power conversion apparatus in order to comprehensively reduce switching loss and conduction loss arising in a switching element. A base current supplied to the switching element is controlled based on the detected collector-emitter voltage so as to control the collector-emitter voltage or control a regenerative power to be transmitted from a switching element driving power supply to an external auxiliary power supply or the like. This provides an optimum driving in consideration of factors including dispersion in a specific current amplification factor (hfe) of the switching element, variance in the hfe caused by temperature, and variance in the hfe to a current flowing through the switching element, for reducing a sum of conduction loss and driving power of the switching element.
摘要:
A premixed combustor for a gas turbine, comprises, a combustion chamber for burning a fuel with an air therein, at least two premixed fuel/air mixture outlets which are juxtaposed with each other, and through each of which a premixed fuel/air mixture flows out into the combustion chamber, and a flow deflection member arranged between the premixed fuel/air mixture outlets, urging the permixed fuel/air mixture from one of the premixed fuel/air mixture outlets to go away from another one of the premixed fuel/air mixture outlets, and terminating in the combustion chamber so that the premixed fuel/air mixture from the one of the premixed fuel/air mixture outlets is permitted to move toward the premixed fuel/air mixture flowing out from the another one of the premixed fuel/air mixture outlets after going away from the another one of the premixed fuel/air mixture outlets.
摘要:
The present invention provides a boost switching power supply with low switching loss. The boost switching power supply of the present invention includes a coil portion 3a and a first diode 4 that are serially connected between one terminal of a DC power source 2 and one terminal of a first capacitor 5 for smoothing, a first switching element 8 connected between a node A where the coil portion 3a and the first diode 4 are connected and the other terminal of the DC power source 2, a second magnetic element 7 and a second switching element 9 that are serially connected between the node A and the other terminal of the DC power source 2, and a second diode 10 and a second capacitor 11 that are serially connected between a node where the second magnetic element 7 and the second switching element 9 are connected and the node A. According to the present invention, the switching loss of the second switching element 9 is reduced substantially because when the second switching element 9 turns ON, the increase of the current flowing in the second switching element 9 is restricted by the second magnetic element 7 and when the second switching element 9 turns OFF, the increase in voltage across the electrodes of the second switching element is restricted by the charging the second capacitor 11.