Function test cabinets Inverter Testing

What are function test cabinets?

The functional test cabinet is a central component of an end-of-line test bench. During the EOL test, the inverter to be tested passes through several stations that perform various tests such as insulation testing, marking or packaging. The function test cabinet is the part that contains the intelligence and sequence control of the prescribed tests, as well as the electronics for the test.

More flexibility for cost-efficient solutions
We offer you the option of building the EOL test station yourself, whilst only purchasing the function test cabinet from us. In that way, you receive a solution tailored to your needs, cost-efficient solution

Find out more about functional test cabinets from our experts.

Your benefits

Selection of components


The function test cabinet is used in a wide variety of areas. Accompanying development as a relief option or test cabinet for long-term testing up to the final testing after production. You can define the required components of the function cabinet with us, and we will put together the required test equipment for you individually.

600V – 1000V

Diverse range of services

We provide function test cabinets for various power classes, from 600V to 1000V systems, to meet different requirements.

Tests with active load

Realistic quality control

With an active load, we test the entire performance path under real conditions, enabling thorough and practical quality control.

Comparison of test methods: Active load vs. passive load

When testing inverters, we are faced with the decision between two approaches: the active load and the passive load. Let’s take a closer look at these two methods and find out which approach is best suited to your requirements.

Active load – The all-round test

With an active load, around 70-80 % of all required test cases can be accommodated.

When testing inverters with an active load, real power is shifted. This means that further power electronics are connected to the U, V and W outputs of the inverter, and the real power is fed back to the intermediate circuit after the AC-DC conversion, thus closing the circuit. Although this AC-DC conversion makes the tests more expensive, as additional power electronics are required, it offers some key advantages.

The obvious advantage of the active load is that it puts a load on the inverter starting from the input terminals on the DC side through to the output terminals on the AC side. This is particularly important for long-term and endurance tests in order to approach the operating point of maximum power dissipation and to test the correct connection of the power electronics to the cooling circuit. Deviations from production can be detected and rectified here, making the active load an effective quality assurance measure. Of course, this comprehensive audit is associated with higher costs.

Prices & delivery times: A fully equipped functional test cabinet including active load, power supply unit, rotor position sensors and safety technology is available starting at €120,000 and is delivered within 20 weeks.

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Passive load – cost optimization with restrictions

The passive load uses simple chokes that are connected to the inverter. Here, the real portion of the power is minimal, which means that the DC path is only slightly loaded. This means that the DC input path, where joining and connecting parts are also installed, is not loaded correctly. The currents that would be expected in a normal application do not flow at this point. The focus is only on the correct function of the power module. This approach is more cost-effective and offers an interesting alternative.

Prices & delivery times: A test cabinet with passive load (inductance), power supply unit, rotor position sensors and safety technology is available starting at €75,000 and is delivered within 20 weeks.

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The best of both worlds – a combination of active and passive loads

In the end-of-line (EOL) phase, in which the correct installation of the inverter is checked, opinions differ. Some rely on EOL testers with a passive load, while others swear by a 100% test with an active load.
The golden mean in this case would be EOL test systems with a combination of several nests of passive load and active load. In this way, a 100% inspection can be carried out on a sample basis to validate batches. For example, after 500-3000 inverters have been passively tested, it would be conceivable to test five inverters using an active load over a period of several days.

The AUTFORCE advantage – The consultant role
At AUTFORCE Automations GmbH, we support our customers to find the best solution for their specific requirements.
Our strengths lie in our excellent market insight and years of experience in the industry. We understand the requirements of decision-makers and offer tailor-made solutions that maximize commercial benefits. When it comes to optimizing your test procedures, we are the right partner at your side.

Do you also need a solution in the field of inverter testing?

At AUTFORCE, we specialize in testing systems & industrial software. specialized Get in touch with us. Together we will find the best solution for your project!

Rainer Jung
Inverter testing expert
+49 (160) 922 32 797

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