Screening Insulation Testing

Referenz WSK Elektronik

Screening Isolationsprüfung

Endurance Insulation and Breakdown Testing with Environmental Simulation (Condensation Test)

Our system for service life evaluation of electrical components measures insulation resistance as well as insulation and dielectric strength over the service life under increased stress conditions. An accelerated life test is carried out in the climate and environmental simulation screening chamber.

The Test Units

Typical test units include stator windings of electric motors, other enamelled wire coils, switches and push-button elements, sensors and actuators with insulating circuits, and devices in protection class I (protective earth). The method can be applied to any endurance application that requires insulation testing or measurement.

The Test System

The system consists of a climate and environmental simulation chamber and our intelligent insulation tester. Depending on the application, this is either a simulation chamber with humidity control or a temperature-only chamber. Inside the chamber, the test units are mounted in a suitable fixture and electrically connected to the test and measuring equipment.

The insulation tester comprises a measuring computer and a combined high-voltage unit. Both AC and DC high-voltage tests (AC/DC HV) can be performed. Test voltages are adjustable up to 1,000 V; higher voltages are available as an option.

The Test Procedure

The application presented here provides for a multi-stage test of up to 90 test units:

  • Immediately after installation, the initial insulation resistance of the test units is measured. DC test with selectable voltage up to 1,000 V.
  • This is followed by the continuous breakdown test with climate simulation over several days, weeks or even months. Here it is performed with AC voltage such as 230/440 V up to 1,000 V, adjustable in 1 V steps. Special conditions can be programmed, such as lower voltage with humidity or higher voltage without humidity. The breakdown current is measured and monitored throughout the entire test period. Defective units, i.e. those that have broken down, are automatically removed from the test, and the time of breakdown and breakdown current are recorded.
  • At the end of the endurance run, a final insulation resistance measurement is carried out on all parts that have not broken down (“good parts”). Together with the initial value, this provides a statement on insulation behaviour over the service life.
  • Finally, before the test units are removed, the breakdown voltage can be determined. To do this, the test voltage is increased continuously until the point at which the test unit breaks down.
  • In this application, the test units are divided into three independent groups of 30 each. An independent test voltage can be set for each group.
  • A log file records all test events; measured values and times (e.g. when breakdown occurred) are displayed in a table and saved to a measurement file.
  • The test is very clear to follow: despite the large number of test units, the current test status can be seen at a glance.
  • All relevant data are stored for subsequent process analysis.

Your Application

The voltages, currents, number of test units and tests mentioned above are examples from a range of our applications and can be adapted individually to your needs. It is possible, for example, to integrate actuation of the test units with a function test, or mechanical stress such as bending of connecting cables, into the endurance run. There are no limits to your requirements. Simply send us your requirements specification or talk to our application engineer!

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