hipotester

A hipotester, short for high-potential tester, is a device used to perform dielectric withstand tests on electrical equipment and insulation. The primary purpose is to verify that insulation can withstand a specified high voltage without breakdown, thereby ensuring electrical safety and reliability. Hypotesters can apply either direct current (DC) or alternating current (AC) high voltage and monitor the resulting leakage current to determine dielectric strength.

Most hipotesters include a high-voltage source, a controllable voltage ramp, leakage-current sensing, and safety interlocks. They may also feature automatic discharge of the test object after a test and compliance with safety standards. Portable models exist for use on the production floor, while benchtop or rack-mounted units are used in laboratories. Some devices combine hipot testing with insulation resistance measurements.

They are widely used in testing electrical appliances, power supplies, cables, transformers, motors, and medical devices. The tests can be performed as part of incoming quality control, in-process testing, or final product verification. They help identify weak insulation, contamination, or manufacturing defects that could lead to equipment failure or safety hazards.

Standards and safety considerations: Dielectric withstand tests are defined by standards such as IEC 61010 and product-specific requirements (for example, IEC 60335 for household electrical appliances or IEC 60601 for medical equipment). Test voltages and durations depend on the equipment and its operating voltage. Operators must follow safety procedures to protect against electric shock and the release of stored energy, and to prevent electrical arcing or equipment damage.

Limitations: A hipot test subjects insulation to voltages higher than normal operation; some materials may exhibit partial discharge or aging effects. The test can cause damage if misapplied or if the device under test has residual voltages, so proper discharge and safety interlocks are essential.