Showing papers on "Impulse generator published in 1991"

Adjustable pressure dual piston impulse clutch

Abstract: A hydraulic torque impulse generator (10) uses a dual piston arrangement to provide impacts to a rotative anvil (20) and automatic shut-off and control (42, 44, 46, 48) for limiting the pressure without reversing the direction of the driving clutch cage (22), a pressure venting arrangement (34) permitting one impact per revolution.

Usefulness of SPICE in high voltage engineering education

Abstract: The usefulness of the SPICE circuit analysis program is demonstrated in high voltage engineering education, where assembling the actual circuit might be very time-consuming and costly and hand calculation techniques could be very complicated. Two representative high-voltage generating circuits are simulated. One is an impulse generator and the other is a voltage multiplier. The first circuit is analyzed for the dependence of the risetime of the impulse voltage on the values of the wave-front resistor, line inductance, and load capacitance. A three-stage impulse generator is also simulated to determine the effects of wave-front and wave-tail resistors on the voltage waveform. The second circuit is analyzed for the dependence of the output voltage and ripple on the load resistance and output capacitance. SPICE can similarly be used for most high-voltage systems in the laboratory, making use of students' time much more effective as well as limiting their exposure to very high voltages, ensuring personal safety in the laboratory. >

Photoconductive impulse generation and radiation

Abstract: The generation of extremely narrow, high peak power pulses using an optically activated impulse generator is described. Radiative measurements at 1 Hz PRF have been conducted at pulse bias levels up to 15 kV, using an optical pulse from a Nd:YAG laser to trigger the device. The measured pulse from a wideband antenna has a pulsewidth of 1.5 ns with a risetime of 900 ps. The frequency spectrum of this radiated waveform ranged from 50 MHz to 1 GHz. >

Pulse generating valve for flushing pipework - has impeller driven pulse generating valves to supply water and air mixt. without external power supply

Abstract: The pulse generating valve supplies an impulse stream of water-air mixt. to flush out the pipework system. The valve is in three parts: a main water flow and turbine drive to the other valve parts; a water impulse generator; and an air impulse generator. Air and water are obtained from the site compressor and public water supply. The freq. and shape of the impulses can be regulated to give the desired cleaning action. ADVANTAGE - Can use readily available water and air supplies. Does not required electrical power supply. Compact dimensions and low cost.

Monolithic, photoconductive impulse generator using a GaAs wafer

Abstract: A new technique for generating multikilovolt, nanosecond pulses was demonstrated. The technique relies on the use of a semi‐insulating GaAs substrate, which performs the dual functions of energy storage and switching. The energy storage was realized by fabricating disk‐shaped electrodes on a 7.5‐cm‐diameter GaAs wafer, thereby forming a radial transmission line. A mode‐locked Nd:YAG laser was used to activate the switch, which is vertically fabricated in the central region of the substrate. This device generated and delivered about a 2 MW pulse with a rise time of less than 500 ps to a 50 Ω load.

Improved electrical switching system

Abstract: A manually controlled switching unit 10 or 11 incorporating a high voltage impulse generator is linked to a receiving unit 13 via an electrically conductive path 14 or 15, and the receiving unit 13 turns a load 16 ON and OFF in response to such impulse Successive impulses may toggle the load between ON and OFF states or it may be turned ON by a positive pulse and OFF by a negative pulse or vice versa A plurality of switching units and receiving units may be interconnected by a single line, the switching units producing outputs which can be distinguished from one another on the basis of patterns of positive or negative pulses, or pulses of different widths or amplitudes The receiving unit may be incorporated in an adaptor interposed between the load and a power supply socket for the load The impulse generator may be energised by a dynamo, solar coil, battery or particularly a piezoelectric device The load may be a domestic, commercial or industrial appliance such as a motor, television set or, particularly, a lamp

Hydraulic torque impulse generator

Abstract: Sealing means 12, 13, 14, 16, 18, 19, 26, 27 on an impulse-receiving rotor 3 and a rotatable mass 1 (defining a hydraulic fluid chamber 2) periodically delimit high and low pressure regions H and L n times per revolution of the mass 1 relative to the rotor 3. The rotor 3 has bypass bores 28, 29 opening at its periphery and cooperating with the periphery of the chamber 2 so as to communicate between the high and low pressure regions (as in Figure 11) n-1 times per revolution, in such a manner that only one torque impulse is generated (as in Figure 13) per revolution.

Bit and frame synchronizing unit for an access node in an optical transmission device

Abstract: The bit and frame synchronizing unit (51) described is designed to synchronize an access node with the bit stream passing along a fibre-optic cable. The unit (51) has an electrically controlled optical switch (57) used as a light switch. It also has a sequence indicator (75) for electrical control of the switch (57), an impulse generator (72), an electro-optical converter (60), an electrical integrator (63), an adjustment and weighting unit (66) and a control unit (69). The unit (51) also has a coarse-adjustment device (48). An optical bit pattern (BM) appears periodically at the input (53), and at the control input (44) an associated equivalent electrical reference pattern (VM). The size of the resultant electrical voltage pulse (U) at the output (64) of the integrator (63) is, in an approximately synchronous-running state, a measure of the phase difference between the two. In the case of perfect synchronization, a sharp impulse peak occurs. The unit (51) is intended for the simultaneous synchronization of bit and frame phase.

Electronic control of impulse generators

Abstract: The authors present a scheme for electronic control of firing of a 140 kV impulse generator equipped with a trigatron spark-gap. The trigatron gap is triggered by a pulse produced by a triac circuit.

Drive control for conveyor belt feed - with impulse generators on drive motor for accurate movement control

Abstract: The continuous drive belt system pulls the workpieces through the different process stages, while external elements move the workpieces to and from the belt, hold the items for processing etc. The accurate position control of the belt is derived from at least two impulse generators (DR1,DR2) coupled directly to the main drive motor. Only single position switches are required for each process stage. The main processor control operates using the impulse generator outputs as well as the position control signals to monitor the movement of the items. ADVANTAGE - Accurate position control, only requires half the usual position control switches i.e. only one from each conventional pair.

Pulse generation and measurement of radiated waveforms from an optically activated impulse generator

Abstract: The generation of extremely narrow, high peak power pulses using an optically activated impulse generator has been demonstrated. Radiative measurements at 1 Hz pulse repetition frequency have been conducted by pulse biasing this device up to 15 kV and subsequently triggering the device with an optical pulse from a Nd:YAG laser. The measured pulse from a wideband antenna had a pulsewidth of 1.5 ns, with a risetime of 900 ps. The frequency spectrum of this radiated waveform ranged from 50 MHz to 1 GHz. The peak field improved substantially as the bias voltage was increased from 9 kV to 15 kV. This may be attributed to the faster risetime at higher bias voltages, which can be radiated more efficiently. >