摘要:
A method and an apparatus for controlling the operation of the synchronous motor are disclosed in which the synchronous motor is started with a starting power supply and operated with a steadying power supply. The starting power supply is adapted to alternately repeat acceleration and deceleration of the synchronous motor in the neighborhood of the frequency thereby to bring the synchronous motor into the point where the synchronous motor is in synchronism with the steadying power supply. The starting power supply comprises a current control circuit and a phase angle control circuit, which circuits control the motor current in such a manner as to prevent the voltage drop due to the synchronous reactance of the motor from exceeding the induced voltage of the motor, while at the same time controlling the power factor angle to be in the range from a lead 90.degree. to the angle corresponding to a maximum output point produced by said motor current.
摘要:
Shortcircuit in an arm including a series connection of GTO's and reactors of an inverter is detected by sensing a voltage across the reactor. In one method, the shortcircuit in the arm is detected when voltages are coincidently applied to a P-line arm reactor and an N-line arm reactor for a predetermined time period. In another method, it is detected when an integrated value of a voltage across at least one of the reactors exceeds a predetermined level.
摘要:
In the control of a synchronous motor driven by a power converter of voltage source type, the phase of the current flowing into the motor is detected and gate signals are produced on the basis of the phase of the current, so that the output frequency of the power converter is controlled by the gate signals so as to control the motor.
摘要:
A gate circuit for gate turn-off thyristors is disclosed which includes a turn-on circuit formed of a series combination of a turn-on power source and an NPN transistor and a turn-off circuit formed of a series combination of a turn-off power source and a thyristor, and in which a PNP transistor is provided between the anode and gate of the thyristor in such a manner that the base of the NPN transistor and the base of the PNP transistor are connected to each other and a junction of these bases receives a control signal for turning on or off a gate turn-off thyristor.
摘要:
A control circuit for a semiconductor element with a control electrode includes a signal transmission circuit, in which two switching elements made conductive when a control signal is supplied from a control signal source to the switching elements through a signal insulating element, are provided so that the control signal is transferred to a turn-on circuit for the semiconductor element only when the switching elements are simultaneously made conductive.
摘要:
A control device for a pulse-width modulated inverter comprises means for generating as a carrier wave a triangular wave synchronizing with an AC output from the inverter, means for generating as a modulating wave a train of rectangular wave pulses which synchronize with the triangular wave and have a width corresponding to a section effective for a modulating operation and a predetermined amplitude, voltage level setting means for setting the amplitude of the train of rectangular wave pulses, and means for modulating the triangular wave with the train of rectangular wave pulses and generating a control pulse for the AC output. The rectangular wave pulses are so set as to have a modulating level of zero in the proximity of a point corresponding to the zero point of the AC output of each phase thereby to remove a frequency divider for adjusting input frequencies of the triangular wave generating means and the modulating wave generating means and to prevent a useless modulating operation leading only to an increase in the number of commutations of the inverter.
摘要:
When a power conversion apparatus such as inverter or chopper comprises gate turn-off thyristors (GTO's), current limiting reactors are connected to cathodes of the GTO's and opposite ends of each of the reactors are connected to positive and negative terminals, respectively, of a gate power supply which supplies a turn-on current and a turn-off current to the respective GTO. With this arrangement, an energy stored in each of the reactors at the turn-off of the GTO is absorbed by the gate power supply.
摘要:
A battery pack is provided. The battery pack includes: a generator device having a battery element disposed on a flexible covering material folded to cover the battery element, wherein three sides of the flexible covering material around the battery element are sealed; a rigid covering material for covering the generator device, having an opening and being bonded to the flexible covering material of the generator device; and a cover fitted into the opening of the rigid covering material, wherein the rigid covering material has a three-layer structure having an outer packaging layer, a metal layer, and a heat-bonding layer which are stacked on one another, and the heat-bonding layer is one selected from an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid copolymer, an ethyl acrylate copolymer, a methyl acrylate copolymer, a methacrylic acid copolymer, a methyl methacrylate copolymer, polyacrylonitrile, an ethylene vinyl alcohol resin, a polyamide resin, a polyester resin, acid-modified polypropylene, or an ionomer.
摘要:
A metal vapor discharge lamp. The metal vapor discharge lamp includes an enclosed discharge tube having a pair of main electrodes mounted at spaced apart locations therein, the discharge tube including a fill of at least a metal vapor and a starting gas, a radiation source including radioactively impregnated ceramic material having a vitrified radioactive outer protection portion and an outer bulb for enclosing the discharge tube and a circuit for electrically generating an arc between the main electrodes.
摘要:
Disclosed is a cytoprotective agent for use with respect to ischemic damage, including as an active ingredient a triprenyl phenol compound represented by the following general formula (I), wherein X is —CHY—C(CH3)2Z, Y and Z are each independently —H or —OH, or jointly form a single bond, and R represents a hydrogen atom or a substituent with a molecular weight of 1000 or less.