Safely operating electric motors and generators depends on one small detail: reliable insulation.

High-voltage mobility

Find out which materials can be used in your eDrive motors

The automotive market is in a state of upheaval; electromobility is on the rise around the world. While a 12-volt battery used to be the standard in vehicles, future drivetrains will be equipped with 800 volts and more. Because of this, the voltage on board a vehicle can reach a level where discharges and partial discharges can occur. Without proper insulation, this could destroy the motor.

Leading system for high-voltage stress

We work with OEMs, suppliers, and motor manufacturers to test which resistant materials can be used for their products based on their specific requirements. Our system for high-frequency high-voltage stress is one of the world’s leading systems of its kind.

We test motors under inverter conditions. A frequency converter converts pressure on the gas pedal into electrical impulses. This exposes the insulation material to significantly higher voltages, a higher frequency and increased temperatures. At the end, you receive a test report and recommendations for your insulation system.

Von Roll has over 100 years of high-voltage expertise. This is why leading pioneers in electromobility trust in us.

The fundamental compatibility and thermal resistance of components in a low-voltage electrical motor or generator can be determined in tests such as sealed tube, twisted pair, and helical coil tests. We carry out these tests at our laboratory in the USA, according to UL-certified standards.



  • Please contact one of our experts if you require more information on these tests.

Motorettes are low-voltage stator models. Similar to the formette test, these are examined under continuous thermal exposure with reference to the temperature index. The temperature index can be extrapolated from the downtimes of the various temperatures. We carry out these tests at our laboratory in the USA, according to UL-certified standards.



  • Standards: IEEE 1776, IEC 60034-18-21, IEC 60034-18-31
  • Please contact one of our experts if you require more information on this test.

Environmental test chambers, a condensing chamber and a low-temperature chamber are used to simulate specific climate conditions.



  • Max. temperature: +40°C
  • Max. relative humidity: 99-100%
  • Min. temperature: -45°C

In more than 15 furnaces, long-term storage of test pieces is performed in order to measure reductions in weight or mechanical parameters after a defined storage period.



  • Max. aging temperature: 350°C
  • Max. dimensions: 750 x 450 x 250mm
  • Max. weight: 30kg

We use a vibration table to expose aged and unaged test pieces to mechanical stress.



  • Max. weight: 30kg
  • Acceleration: 1.5g
  • Vibration frequency: 50Hz

Measuring partial discharges under surge voltage has become an important part of the IEC test. The surge voltage also enables you to check the functionality of the coil being tested.



  • Standard: IEC TS 61934, IEC 60034-18-41, IEC 60034-18-42
  • Max. pulse amplitude: 11kV

We have developed a system specifically designed for performing voltage endurance tests on traction and wind insulation systems. The high-frequency sine-wave voltage with a maximum test frequency of 1000Hz and up to 7kV RMS value can also detect partial discharge problems and show the resistance against them.



  • Standard: IEC 60034-18-42
  • Max. test voltage: 7kV
  • Max. test frequency: 1000Hz
  • Max. dimensions: 800 x 500 x 300mm
  • Max. test temperature: 200°C

In this test, the test pieces (e.g. twisted pairs, motorettes, and coil models) are exposed to a high-frequency square-wave voltage until breakdown. With repetition rates of 30kHz, a voltage amplitude of up to 5kV, and a rise time of around 25ns, the multi-channel system is unparalleled anywhere in the world. This test takes place in a furnace, enabling testing under real-life temperature conditions.



  • Standards: IEC 62068-1, IEC 60034-18-42
  • Max. test voltage: 5kV
  • Max. pulse repetition rate: 30kHz
  • Max. test temperature: 200°C

Learn more about our further tests

Electrical thermal

Mechanical thermal

System tests

Fire tests