摘要:
A safety apparatus for an elevator system is disclosed in which upon detection an instantaneous power service interruption, an emergency brake is applied to the car and continues to be applied for longer than the time required for the particular car to stop.
摘要:
A power converter for power conversion between an a.c. system and a d.c. system includes a full-wave bridge circuit having GTO connected in at least one arm of the full-wave bridge circuit on the positive polarity side. During a conduction-enabled period of GTO which is determined by a firing phase angle, the GTO is so controlled as to perform current chopping operation by a pulse signal of a predetermined pulse width.
摘要:
A thyristor fault-detecting apparatus comprises a thyristor bridge with A.C. terminals connected to a three-phase A.C. power supply and having six thyristor arms, and an inductive load connected to D.C. terminals of the bridge. Each of the A.C. paths has a saturable reactor with an output winding so set as to be excited by the line current within the range from .pi./3 to 2.pi./3 (rad). Output voltages of the reactors are rectified and added, so that a fault in the thyristor is detected by the disappearance of the added output.
摘要:
A speed control system for an elevator motor, comprising a D. C. motor for driving an elevator, a device which generates a speed command signal for the elevator, a speed dynamo which generates a speed signal corresponding to a speed of the elevator, a speed control device which adjusts an applied voltage to the motor according to the speed deviation between the speed command signal and the speed signal, an emergency stop device which subjects the elevator to braking when the speed deviation has exceeded a predetermined value, and a blind sector device which provides an output when the speed signal has exceeded a predetermined value and which negatively feeds it back to the speed control device.
摘要:
In a speed feedback control system wherein a speed command signal and a speed feedback signal are compared and wherein the deviation between these signals is entered into a speed control unit, the speed signal is differentiated to apply speed damping in order to suppress the oscillations of the control system. In this case, while the speed command and the actual speed make a great difference transiently, the speed command is approximate to the sum between the speed feedback signal and the damping signal even transiently. Therefore, the speed command signal is compared with the sum between the speed feedback signal and the damping signal, and the fault of the speed control system is detected upon the fact that the deviation has exceeded a predetermined value.
摘要:
An elevator controller which uses an acceleration command signal that has as its initial value a start shock compensation torque which will offset the unbalance torque caused at the time of starting. From the completion of elevator car acceleration to the start of deceleration, the acceleration command is gradually increased or decreased to control the motor so as to provide a smoother motion of the car. After the inception of the car deceleration a velocity command is issued which decreases with the reducing distance between the car and the destination floor.
摘要:
A dv/dt protection circuit device for an AC-DC converter apparatus including control board switching arrangement having a current cut-off function which conducts an interrupts current from a power source to a load and refluxes the load current while the current is uninterrupted by a full-wave bridge rectifier circuit having a plurality of arms. Each arm of the bridge rectifier circuit connects a reactor for suppressing a rate of change of a power source line voltage of the bridge rectifier circuit at the switching time of the switching arrangement and a condenser is provided for absorbing an overvoltage generated at an inductance on the side of the power source, the condenser being connected on the side of the power source connected to the bridge rectifier circuit.
摘要:
A pulse generator (including a microcomputer) for supplying a pulse pattern to semiconductor devices of a power converter (such as an inverter or a converter) using the pulse width control scheme is provided with function of dropping pulses so that the pulse pattern may form a predetermined function provided that the pulse width is shorter than a limit value (Limit). As a result, the input and output waveforms of the power converter can be made sinusoidal and can be released from the constraint of the minimum pulse width of power conversion semiconductor devices.
摘要:
An elevator control apparatus comprises an inverter device for supplying an induction motor for driving an elevator cage with AC electric power of variable voltage and frequencies and control equipment for controlling the output voltage and frequencies of the inverter device in response to signals produced in floors served by the elevator and in an elevator cage. The inverter device is constructed by a converter unit for converting AC electric power to DC electric power, at the input end of which a capacitor is connected in parallel with an AC electric source, an inverter unit for inverting the DC electric power converted in the converter unit into AC electric power, at the output end of which a capacitor is connected in parallel with an induction motor for driving the elevator cage and a DC reactor connected between the converter unit and the inverter unit.The thus constructed elevator control apparatus does not cause interference in electric appliances such as audio equipment, computer etc. existing within a building in which the elevator is installed.
摘要:
An AC-to-DC power conversion by connecting GTO elements to the positive arms of a three-phase full wave bridge circuit and by repeating the mode of supplying power to a load from an AC power supply by controlling the GTO elements, and the mode of making the current flowing to the load flow back at the time of interruption of the power supply mode, when the power supply mode and the flow-back mode are switched over, overvoltage at the time of the switching is suppressed by simultaneously causing the power supply and flow-back currents to flow.