FEATURE TEST & MEASUREMENT
Measuring tools and devices are vital for any for work carried out on electrical
installations operated with mains voltage. But which device for what purpose?
how do you know which one is the best? The most important things to consider when your are purchasing a multimeter are: the area of use (house electrical system, car, model building); its measuring accuracy; auto range; CAT category; and counts - i.e. the resolution of the built-in screen.
RIGHT TOOL FOR THE JOB
FOR SAFE VOLTAGE TESTING With a Duspol you can conduct pole voltage testing during installation. Alternatively, you can also use the 2-pole voltage tester to determine if a circuit is free of voltage. For example, to test if a socket is voltage free, the test probes are applied to both contacts of the socket. If the indicator light then goes on, there is voltage. It is important to note the phase testers found
in many households (small screwdrivers with transparent handles) are often unreliable. Even if the light indicates no voltage, there can still be voltage present. The reason for such error messages could be the lack of electrical conductivity of the subsurface, for example. This causes the light to light up dimly or not at all. Reliable Results can be achieved only with a voltage tester or a multimeter.
FOR CONNECTION CHECKS Continuity testers will beep to indicate if there is an electrical connection between the contacts. These devices detect short circuits and properly test the function of connections such as cables.
FOR A WIDE RANGE OF MEASUREMENTS Multimeters, also known as ‘multiple measurement devices,’ combine various measuring devices in one. Typical features include a voltmeter to measure the voltage, an ammeter for current and an ohmmeter for resistance. They can often be used as continuity testers too. Furthermore, multimeters can be used for measurements around the design of circuits. In short, multimeters are suitable for any work around home electrical systems. The selection of tools on the market is vast, so
FOR TEMPORAL PROGRESSION OF ELECTRICAL VOLTAGES An oscilloscope is suitable for measuring temporal progressions as they check voltage exactly like a multimeter. A particularly special feature of oscilloscopes is that they can graphically represent different electrical voltages in a configurable time window. You can create two-dimensional graphs on a screen where the horizontal axis represents time and the vertical axis represents the corresponding voltage. Another advantage of the oscilloscope over a multimeter is that the latter device is only calibrated for sinusoidal AC voltages. If the voltage has a different shape, these devices show incorrect values. Only an oscilloscope can detect the voltage form and correctly measure the values, making it the most important tool for electrical engineers who want to properly check the function of certain parts. However, in comparison to the multimeter, it is more difficult to operate and requires some technical knowledge.
reichelt
www.reichelt.com
MAKING CABLE FAULT LOCATION EVEN EASIER M
egger has introduced a new and enhanced version of its popular all-in-one EZ-
THUMP cable fault location system. Designed to be readily transportable and easy to operate. The EZ-THUMP V2 is an suitable choice for first responders, but its extensive capabilities mean that it is also well suited to more demanding applications. The EZ-THUMP V2 incorporates a single- stage capacitor surge discharge system that delivers 500J at 12kV. This is partnered by an integrated time-domain reflectometer (TDR), which facilitates pre-location of low-resistance faults and, by using the arc-reflection method (ARM), high-resistance faults. In addition, the EZ-THUMP V2 can be used in conjunction with an acoustic/electromagnetic receiver to pinpoint the precise location of faults. Sheath testing and sheath fault location are also supported.
18 MAY 2018 | ELECTRICAL ENGINEERING Advanced safety features provided by the
instrument include the F-OHM system that automatically checks that earth connections have been made correctly and inhibits testing if it detects a problem, and facilities for connecting external safety devices such as warning beacons and emergency stop buttons. All of the instrument’s functions are controlled with a single rotary knob, and the test results are shown on a high-brightness colour display that is easy to read even in bright sunlight. No settings at all are needed when the instrument is used in automatic mode – users simply connect the test set to the cable and switch it on. The cable end and the fault location are then automatically detected and displayed. More experienced users can access expert mode to optimise results in particularly challenging applications.
Light in weight
and exceptionally compact, the EZ- THUMP V2 can be powered either from an AC mains supply or from its own internal rechargeable battery. These features mean that it can be used in any location, even where access is difficult and no mains supply is available. The internal battery is designed to have a long operating life but, when replacement eventually becomes necessary, this can be done in the field by the user.
Megger
www.megger.com
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