Showing papers on "Impulse generator published in 1988"

Distortion-free measurement of high impulse voltages

Abstract: It is shown that every high voltage divider has a limited bandwidth of some MHz, resulting in a limitation for the measurement of front oscillations or front-chopped lightning impulse voltages. It is pointed out that a voltage divider can be easily calibrated and can be constructed to prevent EMC-problems during impulse voltage measurement. Using a spherical electric field sensor with optoelectronic data transmission, a voltage measurement system with an upper bandwidth of 25 MHz has been constructed. The advantage of this system is the distortion-free measurement of all impulse test voltages in any circuit. After a short review of the principle and characteristics of the sensor, some practical applications are highlighted, showing that it can improve high-voltage measurement. >

High voltage impulse wave generator for testing equipment

Abstract: A generator for subjecting an electrical apparatus to a surge voltage. The generator includes a surge voltage generator, a line isolation surge filter, wave shaping circuits and a rectifier coupling network for coupling the surge voltages in shunt with the power line and the equipment under test.

The effect of oscillatory switching surges on the breakdown of non-uniform gaps

Abstract: Results are presented of the testing of a rod/sphere gap with oscillatory-switching surges produced in the laboratory. These surges are unidirectional or bidirectional, and the frequency and decay rate can be controlled by varying the resistances, capacitances, and inductances of the components in a modified impulse generator circuit. The resultant output wave can be either unidirectional or bidirectional and of either polarity, and the waveform can be predetermined by analysis on a computer. >

Hydraulic torque impulse generator with bypass mechanism

Abstract: A hydraulic torque impulse generator comprising a rotationally driven drive member (10; 50), a hydraulic fluid chamber (16; 51) confined in the drive member (10; 50), an output spindle (18; 53) having a rear impulse receiving portion (17; 52) extending into the fluid chamber (16; 51), at least two radially slidable vanes (23, 24; 58, 60) carried by the rear spindle portion (17; 52) and cooperating with corresponding seal portions (25, 26; 62, 63, 64) on the fluid chamber wall, axially extending seal ribs (29, 30; 65, 66, 67) on the fluid chamber wall and corresponding axially extending seal ribs (27, 28; 68, 70) on the rear spindle portion (17; 52). Simultaneous sealing cooperation is obtained more than once during each revolution of the drive member (10; 50) relative to the output spindle (18; 52), whereby the fluid chamber (16; 51) is momentarily divided into at least two high pressure compartments (H.P.) and at least two low pressure compartments (L.P.). A first passage mechanism (32-35; 74-78 ) in the drive member (10; 50) cooperates with a second passage mechanism (37, 38; 73) in the output spindle (18;53) to form bypass passages between the high pressure compartments (H.P.) and the low pressure compartments (L.P.) in all but one of the fluid chamber dividing positions, such that only one torque impulse per relative revolution between the drive member (10; 50) and the output spindle (18; 53) is generated.

Shock wave generator for ginding calculus

Abstract: PURPOSE: To precisely observe and position a calculus with a compact structure by providing central opening parts on a coil support body, a flat coil, and a metal diaphragm, respectively, so that the ultrasonic head of an ultrasonic transmitter-receiver can be inserted thereto CONSTITUTION: The impulse source 3 of an impulse generator 1 and a lens device 6 have central opening parts 9, 10, respectively, both the opening parts 9, 10 are mutually connected by a tube body 11 The impulse source 3 of the impulse generator 1 generates a flat wave-like impulse, and this impulse is focused to a focus F by the acoustic lens device 6 Since an ultrasonic head 12, for example, a sector scanner is arranged in the central part of the impulse generator 1, its central axial line is similarly directed to the focus F Therefore, regardless of the rotating direction of the ultrasonic head 13, or the direction of the sector ultrasonic wave, the focus F can be regularly detected by the ultrasonic wave Thus, a calculus can be detected ultrasonically, and it can be visually confirmed through a monitor

An impulse generator for antenna measurements in the time domain

Abstract: Practical details are given of an impulse generator delivering 15 V to a 50 Omega load with a rise time of 70 ps and FWHM 175 ps. Special attention to the settling time (500 ps to 40 dB down) makes the generator suitable for antenna reflection and transmission measurements from 0.1 to 10 GHz, without the need for an anechoic chamber.

Calculation of the voltage on earth impedance caused by lightning impulse current

Abstract: In case of lightning stroke into a tower the impulse current behaviour of the ground is of great importance. A simplified model for estimation the lightning performance of grounding electrodes has been evaluated. Based on field theory the inductive character of the earthing impedance is explained. With the help of computer calculations the role of influencing parameters is discussed as well. An approximate formula is derived which helps the practical computation of the maximal voltage peak.

Hydraulic impulse generator

Abstract: The hydraulic impulse generator consists of a liquid-gas accumulator which is connected with the water supplying tube and the oscillator. The housing of the oscillator contains a hollow piston which partitions the housing chamber into a sluice opening sub-chamber and a sluice closing sub-chamber. The housing also contains low-pressure sub-chamber with a sluice nozzle, and a high pressure sub-chamber, which is connected with the working nozzle. This generator has a device for controlling the movement of 8 and connecting with. Device also contains a controlling valve. is separated from the internal chamber of and connected with. It is also connected with the air through the controlling value of device.

Comparison of methods suggested for conveniently reproducing lightning overvoltages

Abstract: The author presents the results of experimental work carried out to make a comparative evaluation of three different methods of generating very short-tailed lightning impulses (STLI) representative of certain kinds of overvoltages affecting overhead lines. These methods, called B, H and I, are all variants of the Marx circuit. B is one of the standard configurations of the Marx circuit, namely that which provides for an external resistance only. H is a modification of the impulse test plant, which consists in switching in the tail branch through a spark-gap. I is yet another modification of the impulse generator, which can be obtained by series-connecting an inductance of properly chosen value to the tail resistance. All three solutions are shown to solve elegantly the problem of generating STLI with good voltage efficiency and acceptable waveshapes. >

Device for influencing a switching apparatus

Abstract: of EP0255658The invention relates to an arrangement for influencing, particularly blocking, a switching apparatus, preferably a remotely controlled switching apparatus, in dependence on mains condition data by means of feeding in an external voltage and a subsequent evaluating circuit with setpoint and actual-value comparison. For the purpose of feeding in the external voltage, an impulse generator for generating test pulses and an evaluating circuit is provided here which determines the peak value of the instantaneous electric power converted in the motor. This allows short circuits, inter-turn shorts and interruptions in the feedline to be detected reliably and rapidly in a motor.