Abstract: An alternating voltage detector having a sensor for the detection of an electric alternating field, an electrical signal transducer connected to the sensor for signaling an electrical alternating field detected by the sensor, and an indicator unit connected to the electrical signal transducer for the indication of the signaled electrical alternating field, has an interference pulse filter arranged between the sensor and the electrical signal transducer which filters out electrical pulses or pulse packets detected by the sensor which have an average pulse duration or average pulse packet duration less than a predetermined time.

Abstract: A test device is described for testing an electromagnetic quantity, such as a voltage or a magnetic field. The test device includes a housing, a sensor arranged in the housing and sensing the electromagnetic quantity, a processing circuit for processing to signals received from the sensor, display elements for displaying the signals processed by the processing unit, a galvanic element for supplying power to the test device, an illuminator for illuminating an area to be tested, and a switch for activating the illuminator. The test device has a small footprint and does not require an external light source even under difficult lighting conditions.

Abstract: The invention relates to a method for determining the loop resistance of a power supply network with a neutral conductor (called N), a phase or external conductor (called L1), a ground or protective earth conductor (called PE), and a fault current breaker (called FI) based on the differential quotient Ri=dU/dI≈(U1−U2)/(I1−I2); whereby U1 is the measured, unloaded network voltage, I1 is the zero current without load, U2 is the measured, loaded network voltage, and I2 is the calculated load current. According to one aspect of the invention, the following steps are provided: Loading of a L1-N loop and determining the resistance RL1 according to equation (1), loading of a N-PE loop with a measuring current IM under a measuring voltage UM which is small enough to avoid triggering of the fault current circuit breaker, and determining the resistance RPE according to the following equation (2): RPE=UM/IM  (2) and determining the loop resistance as RL1+RPE.

Abstract: The present invention pertains to a device and method for determining the sign of a phase angle of a first and second, essentially identical, periodic electric signals on corresponding first and second electrical conductors L1, L2, in particular, to determine the phase sequence in a three-phase power system. The device according to the present invention has a sensing device for sensing of the first signal from the first conductor L1 and of the second signal from the second conductor L2; a trigger device 25 for receiving the sensed first signal and specifying a time reference point and/or a time reference window within the signal period of the first signal and outputting a corresponding trigger signal; and a determination device 31, 32, 33 for receiving the trigger signal and the sensed second signal and determining the sign of the phase angle under consideration of at least the value of the second signal at the time reference point and/or the waveform of the second signal within the time reference window.

Abstract: In a first measurement step, the two test probes of a measurement apparatus are contacted with two of the three phase lines. The measurement apparatus determines the frequency of the three-phase voltage. In a subsequent second measurement step, one of the two test probes is brought into connection with the remaining third phase line. The other test probe is held in contact with the other line. In the second measurement step the voltage level or voltage profile on the third phase line is evaluated inside the measurement apparatus in comparison to the first phase line during one or more time windows of length .pi..

Abstract: Proposed is a continuity tester for a plurality of electric conductors. For this purpose, a signal transmitter for admitting different individual identification signals to such conductors is connected to one of the ends of the conductors, whereby an identification is allocated to each signal transmitter connection. A signal receiver (10) for decoding the different identification signals by means of a decoding device (15) for indicating the allocated identification on a display (16) is connected to the other ends of the conductors. The signal receiver (10) has a sequence switchgear (30) supplying the connected conductors individually and successively with a reference potential in a repeated cycle, whereby the decoding device (15) for decoding the identification signals is formed at least on the one other conductor in each case.

Abstract: A phase sequence indicator with two measuring contacts for contacting with connections of the object to be measured has a grouring contact touchable by the user, an evaluation circuit connected to the measuring contacts and the grounding contact, and an indicating device controlled by the evaluation circuit for indicating the direction of the rotary field. The evaluation circuit has a voltage-testing circuit for detecting the value of the voltage occurring between the measuring contacts, and the indicating device comprises additional indicating elements for indicating the value of the voltage.

Abstract: A process and apparatus for locating and identifying electrical lines in which a high frequency carrier wave, modulated with a four-bit, serial binary code, is transmitted down the line. An electro-magnetic detector is used to locate the particular line bearing this modulated wave, permitting identification of the line without having to make actual electrical contact with the line at the point of identification.