Abstract: A device for determining partial discharge in an insulation system of a rotating electrical machine with low capacitance decoupling has a coupler as a high pass and an adapter device connected or connectable to the coupler. The adapter device has a frequency separating filter for dividing a decoupled signal provided by the coupler into a high frequency signal and a low frequency signal. A mixer is provided for the high frequency signal and the low frequency signal for converting the high frequency signal. An output is provided where the converted high frequency signal is tapped for evaluation by an evaluation device connectable to the adapter device.

Abstract: The present invention relates to a system for monitoring the electric network voltage waveform, comprising: switching means (11) connected to the voltage lines (A, B, C) of a three-phase system, comprising two thyristors (T1, T2) connected to two of the voltage lines (A, B, C) and at least two capacitors (C1, C2) connected to said thyristors (T1, T2), said means (11) being configured to open and close said thyristors (T1, T2) in response to a trigger signal; means for measuring (12) the voltages in said voltage lines and at the input of said capacitors; a thyristor trigger circuit (14) for providing a trigger signal to either thyristor (DT1, DT2) when the voltage in the terminals of said thyristor (T1, T2) crosses zero; control means (13, 23) for giving said trigger order (OD) or not.

Abstract: A method and system are disclosed for measuring a specified parameter in a phase-locked loop frequency synthesizer (PLL). In one embodiment, the method comprises introducing multiple phase errors in the PLL, measuring a specified aspect of the introduced phase errors, and determining a value for the specified parameter using the measured aspects of the introduced phase errors. In one embodiment, the phase errors are introduced repetitively in the PLL, and these phase errors produce a modified phase difference between the reference signal and the feedback signal in the PPL. In one embodiment, crossover times, when this modified phase difference crosses over a preset value, are determined, and these crossover times are used to determine the value for the specified parameter. In an embodiment, the parameter is calculated as a mathematical function of the crossover times. The parameter may be, for example, the bandwidth of the PLL.

Abstract: The electricity distribution network comprises a plurality of interconnection lines for the distribution of electricity among a plurality of interconnection boxes. At least some of said interconnection boxes are combined with a control unit for detection of stray voltage, comprising a transmitter to transmit to a receiver of at least one collecting unit a signal relating to any dispersion.

Abstract: A detector for determining the phase of high AC voltages comprises two inputs for connecting to respective probes which contact the conductors to be tested, a rectifier circuit to which the inputs are connected, a chain of capacitors arranged to be charged in series from the output of the rectifier circuit, an operational amplifier configured as a trip amplifier for providing an output signal when the output voltage of the rectifier exceeds a predetermined value, and a transistor for discharging the capacitors in parallel through a buzzer and a chain of light emitting diodes when the output signal is provided.

Abstract: A receiver for use in receipt of signals on railroad rails which converts the rail signal to a higher frequency and feeds the higher frequency signal into an input transformer. The secondary of the input transformer is in a tuned circuit which is resonate at the higher frequency and which contains a winding of an output transformer. The tuned circuit can be tuned to the higher frequency by series components such as a resistor and capacitor.

Abstract: This vital solid state relay incorporates only passive elements and is intended for use as a replacement for a two element AC track relay in AC track circuits. The local input signal is applied to a transformer whose secondary output, across a Zener diode, is a pulsed, square wave DC with regulated peak. The track input is applied through a noise rejection filter, tuned to track circuit frequency, to a coupling transformer. A series loop registry circuit includes the secondary of each transformer, a DC relay, and a varistor element. The sum of the transformer output signals, due to the Zener diode rectification, has a DC component. When local and track signals are both present and substantially in phase, the varistor switches to its high current condition to pick up the DC relay to indicate an unoccupied track section. Absence of the track input, out of phase conditions, or unmatched frequencies retains the varistor in its low current state and the DC relay releases to register an occupied section.

Abstract: A portable phase angle meter instrument for use on electric utility power distribution systems.A portable phase angle meter instrument is interconnected between two distribution conductors to generate a voltage signal and current signal substantially in phase with the voltage across the conductors and the current in one of the conductors respectively. A potential probe with a conductive hook for interconnection to a first conductor, houses a first capacitor. A current probe assembly housing a second capacitor, has a head for interconnection to a reference conductor. The head has a Hall sensor or a transformer sensor for generating a current signal substantially in phase with the reference conductor current, and a plate for making electrical contact with the reference conductor. The capacitors are interconnected in series between the plate and the hook via a high voltage cable.

Abstract: A vital circuit network, equivalent to a two element, alternating current track relay used as a synchronous detector, has a first input transformer directly coupled across the local track circuit source and second input transformer coupled across the track rails through a band pass filter tuned to the track circuit frequency. The transformers are designed to normally produce secondary output signals of the same range, which are connected into a series circuit network including a second band pass filter, a varistor, a full-wave rectifier, and a protective fuse, with a biased track relay connected across the rectifier D. C. output. From the two voltage signals in the series network, the varistor produces a product current signal which is rectified to provide an output sufficient to pick up the track relay only when both input signals are present, are of the track circuit frequency, and are within a predetermined phase relationship.