METHOD OF COMBINED TESTING OF THREE-PHASE WINDING OF ELECTRICAL MACHINE Russian patent published in 2006 - IPC G01R31/06 

FIELD: electric engineering; measuring technique.

SUBSTANCE: method can be used for inspecting intra-turn isolation and detecting short-circuiting in winding of stator of asynchronous electrical machines. Two pulse sequences superposition is applied to windings of electrical machine from generator with adjusted pulse duration t and delay time t₃; sequences have similar periods of T and opposite polarities of pulses. Delay time t₃ = τ is set between specified pulse sequences. Pulse duration τ and time delay t₃ is subject to change between pulse sequences while meeting the condition of t₃ = τ to reach the k-th harmonic with maximal amplitude at frequency of ω₀=2kπ/T. Meaning of voltage at output of phase detector is fixed, which value is proportional to difference in phases of harmonics with number of n=k, selected from test voltage by selective units, tuned to frequency of ω₀=2kπ/T. Phase windings are subject to place exchange in sequence. Presence of defect in any phase winding is judged from change in voltage at output of phase detector.

EFFECT: improved truth of results of measurement; improved sensitivity.

3 dwg