Electrical apparatus for detecting relationships in three phase AC networks

摘要

An electrical apparatus for visually indicating phase sequence, phase asymmetry and presence of three phases of an AC network comprising two transistors connected by their emitters to a first voltage terminal of the three phase network, the bases of the transistors being connected through diodes to a first voltage terminal and through crosscoupled phase shifting means to two other terminals of the three phase network. The collectors of the transistors are connected through resistors, light emitting diodes and diodes to two other voltage terminals and the emitters of the two transistors are connected through two other light emitting diodes to the first voltage terminal.