Insulation Testers

What you have always known about the insulation test wanted to know.

The insulation test (also known worldwide as the "IR" test) determines the insulation resistance in measuring ranges from kΩ to TΩ. Many test regulations (e.g. VDE, EN, IEC, UL ...) require the measurement and assessment of the insulation resistance.

Why is isolation testing so important?

washing machine, electric motor, luminaire ... these and almost all other electrical products and electrical systems can only be operated safely if they have a high electrical insulation strength.
In the worst case, poor insulation leads to electrical accidents with serious injuries or fatalities, or even to significant product damage.
With the insulation test determine the insulation quality of your test object. The electrical products are tested with test voltages between typically 500 and 1,000 VDC.

In order to achieve almost all areas of the insulation test SCHLEICH supplies insulation testing equipment from 25 V to 50,000 VDC on the basis of a very extensive range.

Where is the device under test checked?

Testing is carried out between all live conductors as well as from live conductors to the housing.

In principle, the insulation test takes place between the same test connections as the high voltage test takes place.

What errors does the insulation test ?

• Insulation weaknesses between any electrical conductors and the protective earth conductor / device housing
• Insulation weaknesses between the electrical conductors
• Poor insulation on air and leakage paths

What are the good/bad criteria?

The assessment of the insulation test is always based on the ohmic insulation resistance, which is between the two poles of the TEST VOLTAGE is measured. It must not fall below an adjustable limit.

Insulation test always with DC.

The insulation test generally takes place with a DCTEST VOLTAGE takes place.

Why?
Test objects often have unavoidable capacities due to filter capacitors or their physical design. Testing with AC would have the disadvantage that these capacities would result in a high capacitive leakage current would flow. The real resistance could not be determined precisely enough under such conditions.
If, on the other hand, the test is carried out with DC, the Capacitance only a subordinate role. After charging the Capacitance only a very small insulating current flows through the insulation resistance.
On the basis of the voltage and of the flowing current is determined by the ohmic law of the insulation resistance calculated.

How will the insulation test ?

Whether manual, semi-automatic or fully automatic: with insulation testing devices from SCHLEICH, every test task can be carried out quickly and efficiently. run.

Our devices are all designed according to the "KISS principle". That is, following the motto: »Keep It Simple and Smart«. This principle serves as a guiding theme for all SCHLEICH products.

For the requirements of production companies provide are more likely to be partially or fully automated insulation testing devices or insulation testing machines. For this purpose, the test devices are equipped with a relay switching panel (relay matrix). These switch the TEST VOLTAGE automatically to the desired inspection points. Manual testing is carried out with a test probe. To do this, the operator guides the test probe by hand from test point to test point. Despite the manual process, however, the inspection can be documented flawlessly. A typical application here is the inspection of electrical products, control cabinets and machines in accordance with the Machinery Directive EN60204.

Test systems of this type have up to 1,000 test connections, depending on the application.

Safe execution of the insulation test.

Working with high test voltages is not without danger. Therefore, appropriate safety regulations must be observed.
In the case of SCHLEICH insulation testing devices, the Test current basically limited. The integrated safety current limitation limits the Test current to max. 3 to 12 mA DC. This limitation allows the insulation testers to be operated without test hoods.

However, a second criterion must also be taken into account:
Due to their design, many test objects have an unavoidable Capacitance. This Capacitance is charged during the test and stores the charge. The maximum stored energy must not exceed 125 mJ (Q = 1/2 x C x U²). Otherwise, the operator could encounter a dangerous electrical impact when touching the test object even after the test. shock due to the residual charge/Residual voltage .
If, after completion of the test, the test device is still connected to the device under test is connected, the tester internally ensures the safe discharge.
However, if this is not reliably guaranteed, test hoods, test booths, light curtains or barrier chains are used as protective measures.

Potential-free insulation test?

In most applications, the potential-free insulation test is used. It is typical for the use of test probes up to 1,000 V DC or safety test guns up to 10,000 V DC. It ensures the highest safety for the operator.
For higher high voltages from 15,000 V upwards, the TEST VOLTAGE single-sided grounded.

What else you need to consider for an insulation test!

In order to insulation test correctly, it must be ensured that the device under test actually with the TEST VOLTAGE . The control of a correctly performed test is carried out by means of two possible variants of contact monitoring:

• Specification of a charging current: Advantageous for test objects that have a Capacitance . If a measurable charging current flows during the switching on of the TEST VOLTAGE you can be sure that the device under test is correctly connected to the tester.
• Measurement of the device under test actual attached voltage: For this purpose, two additional sense lines are added to the test leads with the device under test . This type of measurement is often also called four-wire measurement. The two Sense lines are used to measure the device under test actually attached TEST VOLTAGE. This voltage is compared to a default value. This is why this control method is called stress remeasurement.

What else is measurable with an insulation test?

In addition to insulation test it is also possible to measure the PI (polarization index) or the DAR ("Dielectric Absorption Ratio").
These are not typical safety testing methods. However, they are often used for preventive maintenance.

What are the requirements for a standard insulation tester?

Most national and international standards require a TEST VOLTAGE of 500 V DC.
Many SCHLEICH insulation testers therefore have a variably predetermined test voltages of 50 to 1,000 VDC.

SCHLEICH insulation testers are typically equipped with a responsive electronic DC test voltage source. Depending on the device, this also allows the precise tracking of voltage profiles.

SCHLEICH insulation testing equipment is based on the experience of over 30 years. From the very beginning, the measurement technology was not analogue, but always digital. As a matter of principle, the most modern technologies are always used.

How do you find the right insulation tester?

The number of insulation testers available on the market is large, and the number of configurable features is overwhelming.

If you are interested in your device under test Insulation tests only run , you are well advised to use a single tester. It contains only a single test method, namely the insulation test.

Requires the device under test we also recommend a more comprehensive safety and function check with our combination testers/multifunction testers. This allows various test methods such as insulation, high-voltage and protective earth resistance test conveniently combine in one tester. The test method switching integrated in the test device ensures that no test leads are connected to the test device under test can be clamped manually.
In addition, the combination of safety tests and extensive functional tests is also very common. To function test the tester supplies the device under test additionally with electrical operating voltage to also check the electrical operating characteristics.

Thanks to the intuitive and convenient operation of our insulation testers, every test is fast, precise and cost-saving.

The SCHLEICH Product Portfolio

• TEST VOLTAGE from 25 V up to 50 kV DC
• Measurement ranges of kΩ, MΩ, GΩ and TΩ
• With electronic, automatically regulated TEST VOLTAGE
• With built-in discharge and discharge monitoring
• Standardized interfaces such as RS 232, Ethernet/LAN, USB for PC communication
• 24 V digital I/O for PLC communication
• Expandable to Industrial Ethernet and fieldbus systems for PLC communication
• Virtually unlimited storage space for test plans and test results
• All parameters determined via the software

In addition, we are happy to plan, design and produce for you custom tailor-made solutions:

• Combination testers/Multifunction testers
• Automatic test systems/Test systems with small to complex relay matrix
• Complete test workstations
• Production lines with transfer systems
• EOL workstations
• Large-scale systems

When choosing your insulation tester, also pay attention to the "soft skills" of the provider. We provide Everything you need Accessories and accompany you throughout the entire service life of your insulation tester:

• Professional Consultation with Expertise
• Thorough initial Commissioning
• Regular certified calibration
• After-sales support from our service team
• Service on the phone or on site
• Tailored training courses

SCHLEICH – the world's only supplier of insulation testing equipment to have been awarded the "TOP100 Innovator" seal of approval four times.