Safety meets competence

Hipot testers

The hipot testers of SPS electronic lets you be completely relaxed.

The hipot tester (or hi pot tester) of SPS electronic allow you to perform all hipot tests according to standards. Thus, the devices allow testing of the electrical insulation properties and the dielectric strength of electrical equipment of protection classes I and II. We offer you hipot testers for voltages up to 5,500 V AC or 6,000 V DC at a maximum current of 100 mA / 200 mA.

In short: What is a hipot test and how does it work?

Plasmakugel bei SPS electronic

Hipot test (also called hi pot or HV test worldwide) has by far the highest priority among all of the electrical safety tests. This test of the dielectric strength is mandatory as it is part of the requirements of all national standards (e.g. VDE and UL) and international standards (e.g. EN and IEC). The often used term insulation test or insulation measurement is wrong in this context as a real, ohmic resistance is measured with the direct voltage in this case. In contrast, the hipot / hi pot test is carried out with both direct and alternating current. The result of this test is a leakage current, flowing between live parts and the metallic casing. Devices of protection class I always come with a metal casing, whereas the casing of the devices of protection class II must be replaced by a metallic contour during the test. In reality, the hipot test is a geometric distance measurement in the DUT (Device Under Test): If the DUT withstands a certain voltage without flashover, an appropriate minimum distance between the metal casing and electrical components in the device is ensured. Thus, the term withstand voltage is also plausible again.

Requirements to be met by the hipot tester

Some national and international standards specify a rating of greater than 500 VA for hipot testers. Furthermore, a permanent current of 100 mA with a short circuit current of 200 mA is required. This is because of the fact that there are many tests that have such capacitances owing to their design. This creates reactive currents, which must be generated by the hipot / hi pot tester or the multifunction safety tester. Due to these reactive currents, the hipot test equipment must generate a voltage ramp. This means that the voltage is not abruptly, but smoothly ramped up from zero to the desired value, following which the testing begins. All hipot testers of SPS electronic are fully electronic with analogue or digital technology, and therefore, can easily generate these high voltage ramps without wear. Devices with variable transformers and motor drive are no longer state of the art of the 21st century. Considering other areas, such as mobile communications or renewable energy, even analogue electrical equipment are no longer contemporary.

Direct or alternating voltage?

Digital technologies have the consequence of increasing number of DUT with high capacitances. Testing is rendered impossible at a leakage current of 100 mA. Therefore, the DC voltage test has been taking precedence over the AC voltage test for many years now. In almost all test standards, the user is free to choose between AC and DC voltage for testing. The standards specify multiplication of the AC voltage by a factor of 1.5. This makes the DC voltage test equivalent to the AC voltage test. A high voltage ramp is also necessary for the DC voltage test. Once the capacitances of the DUT are charged, leakage current generally does not flow any longer.

Even if the capacitive reactive currents are disadvantageous, the AC voltage test has a small benefit: The capacitive reactive current is typical for the DUT and it can be used for contact monitoring. Therefore, the hipot testers of SPS electronic allow programming of both the maximum release current and a minimum current. Only when the minimum current is exceeded, the DUT is under high voltage and the test result is accepted. However, the DC voltage test also allows easy contact monitoring. The capacitances of the DUT generate a typical charging current that is monitored by the tester. Each hipot tester made by SPS electronic can program and monitor the minimum charging  current.

Micro-discharges that occur in both AC and DC voltage tests can be evaluated with the devices of SPS electronic. The so-called partial discharge or ARC-detection is a measure of the insulation system of the DUT. These methods are particularly important in applications in digital power electronics (inverter, motor controllers, power supply units etc.)

Another major difference between DC and AC voltage tests results from the application: Thus, the AC voltage is, in principle, much more dangerous for humans as the mains frequency of 50 - 60 Hz can cause ventricular fibrillation. This is not the case with DC voltage. Therefore, an alternating current of just 3 mA is classified as dangerous by the EN 50191 standard (valid only in Europe). With DC voltage, this value can be four times this value, namely 12 mA DC, and still not dangerous to humans.

The development of hipot test equipment at SPS electronic

As early as the beginning of 1990s, SPS electronic developed the so-called "safety-current-limited" testers. These testers have the great advantage of not needing any workstation protection as the high voltage is limited to a maximum of 3 mA AC or 12 mA DC. In addition to the safety current limitation, the devices of SPS electronic are also potential-free, which is also a requirement of EN 50191. Using these two safety techniques, workstations can be designed in a safe, simple, cost-effective and efficient manner.

Accessories for the hipot tester

Often, the hipot tests are carried out manually, for which a suitable link between the operator, the hipot test equipment and DUT is required. The specially developed test probes SP 02 and SP 03 of SPS electronic provide ergonomically and technically optimized connections. The probes with built-in start switch protect the testing personnel, who can hold them comfortably by hand. This aspect is crucial for the testing ergonomics and safety especially when performing hundreds of tests per day.

The test probes made by SPS electronic allow quick, safe and ergonomic testing.
The test probes made by SPS electronic allow quick, safe and ergonomic testing.

Automatic processes, interfaces and remote control

The automatic test has established itself particularly in Europe for cost reasons. Suitable adapters allow fully automatic execution of the hipot test. Each hipot tester of SPS electronic has a number of ports for this application: In addition to the standard interfaces of RS 232, Ethernet / LAN, USB and 24 V Handler Interface, there are also 8 digital outputs and 8 digital inputs with 24 V DC, which can be directly connected to relays or other sensors / actuators. During the test, the 24 V DC signals are read and/or set by the "Programmable Logic Controller" feature. This allows integration into existing systems without additional intuitiveness.

Often, several test points must be tested sequentially with high voltage. The 24 V DC outputs can also be used for this. The high voltage matrix can be implemented with the high voltage relays RL 42 and RL 21, which are also developed by SPS electronic. Directly driven by the hipot tester and easily integrated in the test sequence without additional control and software.

Since all hipot testers of SPS electronic have computer interfaces, they can easily be controlled remotely from a PC. To this end, the proprietary PC software DAT was developed, based on years of experience and numerous customer requests. It is always kept up-to-date by continuous updates of our software developers. 

Development of hipot test equipment at SPS electronic

What makes a hipot tester of SPS electronic so special?

SPS electronic designs and manufactures electrical safety testers with cutting edge technology and highest quality standards. In the process, fully electronic, digital voltage supplies are just as important as sufficient memory for test programs. Our devices can be operated worldwide with power supplies from 90 V to 250 V at 50 Hz / 60 Hz and thus, ready for use everywhere. The number of test programs is virtually unlimited - no user would need so many test programs that our memory of up to 64GB becomes insufficient. There is still enough space for test results. We also produce series devices consistently with all options and interfaces. Thus, our product range only includes a few types of devices, which is not only favourable to the global service but also to the flexibility of our customers. A device can be replaced at any time, all parameters are determined by the software.

For all those, who want more

Merely a high voltage test is often not enough. Thus, a ground bond test is required, e.g. for DUT of safety class I. Our multifunction safety testers are used here. The built-in high voltage matrix allows set up and changeover between a maximum of 18 different types of tests. "Stand-alone" operation or PC operation is possible with the PC software DAT.

There are only a few differences in the operation of the devices of the 1805 series with 10.1'' TFT color display and touch. Device technology and PC technology are very similar.

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