Solenoid voltmeter

A voltage tester is an electrical test equipment, with the presence, in some Spannungsprüfgeräten more, the level of AC or DC voltage to operationally live parts is detected. A distinction is made between Spannungsprüfgeräten for the use in low voltage, these are electric AC voltages below 1 kV, and in the overlying area of ​​high voltage.

High voltage

Voltage tester for used in electrical power engineering AC voltages of 1 kV to 765 kV are specified in the standards IEC 61243-1 and IEC 61243-2. They are typically carried out in the form of up to several meters long, electrically insulated lance which is introduced for testing purposes by hand to the high voltage conductor. By means of a capacitive voltage division is indicated optically and acoustically by a lance mounted in the test circuit, the presence of high voltage. The scope of this test equipment located in high voltage equipment such as outdoor switchgear, substations and in the field of high voltage laboratory.

Low voltage

Voltage tester for low voltage are specified in the standards EN 61243-3 / VDE 0682 Part 401 and are executed bipolar. Voltage Detectors are used in low voltage distribution systems and electrical installations up to 1000 V for fast and safe testing. The exact voltage range in which the auditor may be used, depends on the voltage tester, and is marked on the device, such as 12-690 V. In contrast to phase voltage tester testers provide reliable inspection. They are compared to multimeters easier to use, but do not offer their capabilities and accuracy.

Construction

Voltage tester for low voltage applications consist of a display unit ( for example, measuring work with scale) and two test electrodes ( probes ). One of the test electrodes is integrated into the housing of the display unit, the second is permanently connected via a line with the handle. For the protection of the tester and the tested person are several resistors that limit the test current and divide the voltage to eigentlichem measurement system to a few volts down the device.

(For example, two lines ) contacted with the test electrodes to measure two different potentials. The display of the voltage is depending on the voltage tester via a pointer, LEDs or a digital display. This two-pole grounding examination is independent and is a safe test result may further including tensions between different outer conductors in three-phase three-phase network (TN -S system ) are checked.

There are three different ways to view Spannungspüfern:

Analog voltage tester

For analog voltage detectors it is displayed with a pointer moving over a scale. The test current flows through a moving iron or moving coil measuring system and the pointer is a rash. This measurement system is relatively low with 25-50 kOhm. Thus, a two-hand control is necessary for safety according to the standard. Analog Voltage Detectors are used for their noise immunity preferred energy providers and industry

Voltage tester with LED display for polarity

In this early version, only two LEDs are provided to indicate the presence of voltage and polarity: AC voltage at both LEDs in DC one of the two marked with a plus or minus.

Voltage tester with gradual LED display

The display of the applied voltage is connected via a plurality of LEDs, where different voltage levels are assigned., The test current flowing through an electronic circuit which drives one or more LEDs according to the size of the test voltage. This voltage tester can only show the approximate magnitude of the applied voltage and are thus unsuitable for more tests. Easy handling and maintenance-free, as a rule, no battery is necessary, these auditors are preferably used in the craft.

Voltage tester with digital display

The height of the applied voltage is indicated on a digital display. The evaluation of the voltage is carried out with a microcontroller. The test voltage is divided down by a voltage divider on a voltage between 0 and 3 V, and converted by an analog-to- digital converter into a digital signal. This digital information is offset by the microcontroller and displayed on the digital display as a numerical value for display. Digital voltage tester usually have even more features, such as continuity test for review of ohmic resistance, phase sequence measurement or measurement polarity at DC. In addition to the digital display and LEDs are usually available, so that the tester can display without a battery voltage. Due to the versatility, ease of use and accurate test result digital voltage tester are preferably used in the industry.

Single-pole voltage tester

In the low voltage range of the " single-pole voltage tester " in DIN VDE 0680-6 with current output is standardized in April 1977. This, colloquially known as the "lying pen" called voltage tester has hardly changed over the years, and its use as a voltage tester is not prohibited, but for a finding of absence of voltage by today's standards no longer state of the art.

The term "lying pen" is due to the fact that often no unequivocal statement can be made. It may on the one hand, the illumination of the glow lamp due to excessive ambient light often not be clearly recognized, but it is also possible by capacitive couplings that the glow (though not as bright ) lights up and is misinterpreted by the user. In case of contact at the contact electrode, a contact current of up to 0.5 mA may come to flow, depending on the design of the "lying pen " the full 0.5 mA are also needed to bring the glow clearly shine. Among several possible circumstances ( unintentional high insulation location, very dry skin or cornea ), it is possible that this required current flow does not materialize and the glow is not sufficiently illuminated. The user can visually see no difference between the capacitive coupling and the weak indicator for site isolation.

Non-contact voltage tester

Non-contact voltage testers are praised as a modern tool, but are difficult to be classified as a tester because they have no particular standard. Thus, there is the general standard for the design of test and measurement equipment ( EN 61010-1, DIN VDE 0411-1 ) apply.

An undisputed advantage is that non-contact voltage tester usually accompanied by a high measurement equipment category ( CAT often III/1.000 V and higher). However, the fundamental problem is the capacitive operation of these devices, which is only suitable for the detection of AC and DC voltages matter does not recognize what amount. Many devices also the essential safety feature of a battery-free display, or a display of battery status is missing. A reliable detection of voltages above 50 V AC ( especially since some products react already at 12 V) is often not possible.

Devices of this type are not suitable for " ascertaining the absence of voltage in electrical systems " and some manufacturers have also clearly in the instruction manual out yet non-contact voltage testers have their place, for example, as an aid to find line breaks.

Security

Voltage testers are subject to special safety requirements of EN 61243-3 (VDE 0682-401:2011-02 ) and are divided into measurement categories (CAT I- IV). Since February 2011 edition of the standard by the following main requirements for the test equipment shall apply:

• A voltage tester as test equipment must be reliable ( and regardless of ON / OFF switch, any area code, or battery status ) recognize first and foremost dangerous voltages.
• Incorrect operation must be largely excluded, so the tester must be simple and reliable to use.
• A voltage tester must not endanger the operator. He must be so constructed that under normal conditions of use no flow through the body or electric arc hazards can occur.
• A two-pole voltage tester must be a minimum of measuring instruments Category III (CAT III) correspond.
• Load connection with which the test current of less than 3.5 mA is increased to a maximum of 200 mA can be made only by the simultaneous operation of two buttons ( operation with both hands).

Because of the long transition period until 1 May 2013 it is possible that two pole voltage detectors CAT II are offered that meet the above conditions only partly. From the purchase of such equipment is not recommended.

The two-hand operation under all operating conditions prevents a test electrode lying under voltage can be touched by hand. Voltage detectors are divided into measurement categories (CAT I-IV) and have since February 2011 at least category three correspond to ensure safe protection of personnel.

Voltage tester before and after a test insert, check the functionality. For this, the function of source will be tested with a known voltage to function. Prior to use, because the tester may be defective. After use, because the tester could have had a defect after the test insert.