Triple-frequency Generator Device in Induced Voltage Withstand Test for Assessing Coil Turn-to-Turn



The Triple-frequency Generator Set, also known as the Triple-frequency Test Transformer Device, is a special power supply equipment specifically used for insulation withstand voltage testing of power equipment.

Unlike the "ultra-low frequency" generator we discussed in the previous round, the core task of the triple-frequency generator is to increase the frequency. It converts the input power frequency (50Hz) into a 150Hz triple-frequency power supply, specifically to solve the problem that transformers, voltage transformers, and other equipment cannot have their voltage raised during induced voltage withstand tests due to core magnetic saturation.

⚙️ Core Working Principle

The design of this device is based on the law of electromagnetic induction (

E=4.44fNΦ ). In the induced voltage withstand test, in order to assess the turn-to-turn and layer-to-layer insulation (longitudinal insulation) of the coil, it is necessary to apply a test voltage much higher than the rated voltage (usually 2 times or more).

Magnetic saturation problem: If a 50Hz power frequency power supply is directly used to apply high voltage, the core magnetic flux density of the transformer (

Φ

Φ ) will increase sharply and reach saturation, causing the excitation current to surge, and even burning out the equipment.

Frequency multiplication solution: According to the formula, when the magnetic flux

Φ

Φ remains unchanged, to increase the voltage