Professional, user-friendly & individual DGUV (German Social Accident Insurance) Regulation 3 - Equipment testing

BENNING’s new-generation equipment testers – BENNING ST 755/760 – are amongst the most highly regarded instruments in their category.

Automated, menu-controlled testing of a type S PRCD using the BENNING ST 755

The sustained, high level of demand for BENNING ST 755/760 is proof enough that it was good policy for them to incorporate quality, functionality and user-friendliness when these robust instruments were developed. Users are treated to a modern screen interface and well-organised structures offering ease of overview. The range of tasks in testing is simplified, right down to where work information is being placed on record, thanks to the useful special settings. POWER news had the opportunity to speak to Mr Enck (of the sales division of BENNING’s testing and measurement equipment department) about the advantages and the new functions of this generation of equipment testers.

PN: I expect that the question: “What’s new compared to the previous product range?” is one that has already been asked of you many times. However, could you go through a few of the main details, for the benefit of our readers?

Enck: User-friendliness and efficiency were central concerns in the new development. The hardware was completely revised and combined with high-performance components. 755/760 equipment testers have a colour LCD display with a clear, modern design. After start-up, you immediately realise that this is an authoritative, reliable piece of equipment. When you are running test procedures, you are guided through the menu by crystal-clear symbols and codes. Screen interface response is very rapid – thanks to the high-powered processors and this also helps when running handheld testing procedures. At the present time, these testers make it possible to run complete PRCD/RCD tests on mobile power distribution and they can also be used for testing welding machines. The PC software for managing customers and test data has been made even more user-friendly and dynamic. There was hardly anything else you could wish for, whether setting up your own test cycles or optimising existing ones; and that also goes for the facilities for placing notes on record.

PN: Both of these equipment testers are suitable for the testing of mobile and medical electrical apparatus for the criteria of DGUV (German Social Accident Insurance) Regulation 3 (VDE 0701-0702, VDE 0751-1). Why do we have the choice of 2 models?

Enck: The two systems are used in basically the same way. But anyone intending to apply testing to welding machines that correspond to VDE 0544-4 standards may prefer to opt for the BENNING ST 760.

This model has the necessary filtering circuitry including a variable resistor for measuring true RMS and peak voltage. The integrated filter circuit is a great advantage, otherwise you would need to buy it as an add-on adapter. The required test stages are run automatically by the fact of having selected the appropriate welding machine test procedure. To actively test welding machines that have 16 A / 32 A CEE connectors, you can use the BENNING MA 4 test adapter or alternative adapter solutions.

PN: Test operator sign-in is an innovation which is immediately conspicuous to the user. What is BENNING’s intention with this?

Enck: User administration enables various rights to be issued for persons who are “EUP” (German abbreviation for “personnel holding electrotechnical training”) and the authorised individual. A user who is signed in as “admin” can use the Expert mode with no restriction on his setting of customer-related limit values, individual visual inspections and test procedures. And the administrator can install updates via LAN, WLAN or a USB stick.

PN: With regard to visual inspection: what has changed, here?

Enck: To give you the full picture: there are three test modes. In addition to “standard visual inspection” and “expanded visual inspection” (comprising 18 preset points) there is a “customer-specific” variant available. In the latter mode, the operator can set up and enter his/her own choice of questions.

PN: At the outset, you mentioned that it was now possible to carry out full PRCD/RCD tests on mobile power distribution. Could you give us a bit more precise detail about this facility?

Enck: The correct testing of PRCDs (mobile residual current devices for personal safety) often presents a difficult task for test operatives. In order to simplify this, the ST 755/760 equipment test systems offer fully automated test cycles for the testing of PRCD-S, PRCD-S+ and PRCD-K types and for two-pole and triple-pole RCDs.

Because circuit breaker systems (RCD/FI) of the AC, A, F, B and B+ types up to 300 mA rated current can be tested, our test subjects are also going to include mobile power distribution, from now on. This means that the protection conductor current, the actuation current and the actuation time of on-board RCD’s (in addition to protection conductor and insulation resistances) can now be measured and placed on record.

PN: Are there any other features you would like to describe for us, when it comes to optimising and organising a test operative’s work processes?

Enck: One example worth mentioning is the setting of RPE test repeat, RISO measurement up to 1000 V DC test voltage, the adjustment facilities (zero, test probe and cable alignment), remote control and display mirroring on a PC or on a tablet with the CERN “remote display control” programme. Testpieces, test cycles and visual inspections can be copied straightforwardly. Other facilities available to the test operative include the setting of date, time of day, language, brightness, display of working media requiring replacement and test history together with results.

PN: To what extent are testing and metrology characteristics influenced by new hardware components?

Enck: High-capacity switching relays have been installed, and they have no difficulty in coping with high switch-on currents, so that their service life is very greatly extended. To a very great extent, the “sticking” of relays is avoided. And the equipment tester is now equipped for testing on IT networks. Examples of these non-earthed networks are to be found in laboratories, or in hospital operating theatres.

PN: What should a test operative do if he cannot find an appropriate test procedure – that fulfils the precautions described in hazard assessment – for a testpiece?

Enck: Here, too, there is a solution. A user who is registered as “admin” can use Expert mode on the equipment tester to set up customer-specific test cycles with their own limit values and visual inspection questions. Individual test periods per test stage provide the test operative with the necessary timing dynamics. In this way, for example, the timeframe envisaged for function testing, including active testing of all of the testpiece’s functions and switching circuits, can either be very precisely defined or left “open”.

PN: Do these test cycles have to be set exclusively on the equipment tester?

Enck: BENNING PC WIN ST 750-760 software also fully supports the setting up of new test cycles.

PN: Consequently, admin and documentation software constitutes a crucial tool both for the user and for the customer. Even so, it is licence-free and can be used without restriction throughout the user’s company. What does it include?

Enck: The whole package that goes to make up the equipment tester’s universe must be compatible within itself. Equipment testers and PC software are designed so that virtually no limits are built into the system.

BENNING provides free updates as changes to standards arise or as new functions are introduced. Installation is possible via W-LAN, LAN or USB stick. Downwards compatibility means that you can also work on the basis of the BENNING ST 750 A’s sdf databases, or otherwise these databases can be successfully converted into db formats for the new testers.

Statistics and reports are straightforward and quick to set up. After a customer or a department has been selected, statistics will provide a numerical & graphic display of the quantity of “passed” and “failed” testpieces together with the nature of the critical defects. Because the database contains all of the details of the customer, the test operative and the operating media, it only takes a few moments to set up test reports. You can even automate the integration of a company logo, the date of a report and a signature, using “ReportDesigner”, a program which has been incorporated into the software. All details and measurement results can be exported for further processing, and reports can be sent to the printer or output as PDF files.

Reports and statistics can be straightforwardly produced with a few clicks of the mouse and exported for further processing

BENNING MA 4 fulfils the requirements corresponding to IEC/ EN 61010-1 and DIN EN 61577-16

PN: Are there any new ideas and solutions for the testing of testpieces with CEE connectors?

Enck: As early as the stage of designing our present BENNING MA 2-16 CEE active adapter and BENNING MA 3 CEE passive adapter kit, we had integrated initial steps in the right direction.

In the autumn of 2019, we shall be introducing the BENNING MA 4 CEE adapter kit. This is suitable for active and passive testing and for full 32 A loading of single-phase and triple-phase operating media in conjunction with equipment testers. This can be described as an “all-in-one solution”. This solution combines the previous range of adapter fittings, which was often very diverse, into one single product. And another feature is that you can now have automatic testing of 5-pole operating media.

After completion of the test cycle, measurements are carried out on the protective conductor and insulation resistance, on contact current and protection conductor current, together with function checks on CEE operating media and extension cables. When 5-pole extension cables are being tested, it’s also possible to test the rotating field and to detect if conductors have been connected the wrong way round. Status is indicated by LEDs, in the process. You can decide to connect a low fault current which checks the whole of the test system (self-check).

The BENNING ST 755 and BENNING ST 760 equipment testers have incorporated the BENNING MA 4 active/passive test adapter kit as a directly selectable option. Essentially, these test adapter kits can be used on all equipment testers if they permit the connection of 230 V mains power.

PN: Many thanks for all of this information. No doubt there are customers who will have individual questions and requirements to put to you. In that case, who should they contact?

Enck: In practice, there is a wide range of different requirements and test concepts. Our equipment testers give operators the optimum basis for fulfilling all of these stipulations. We or our regional branches in industry will be glad to help with any questions or product concepts.