Mining flameproof intrinsically-safe AC variable-frequency system suitable for two-speed motor

The invention relates to a mining flameproof intrinsically-safe AC variable-frequency system suitable for a two-speed motor and belongs to the technical field of variable-frequency speed adjusting devices for mining scraper plate conveyers. The system has a simple and reasonable structure, effectively improves the running stability of a scraper plate conveyer, is extended in service life, and is suitable for a two-speed motor. According to the technical scheme, an input power supply is connected with an asynchronous motor via an isolation switch and a high-speed loop. A low-speed loop is connected with the high-speed loop in parallel. An input vacuum contactor is arranged on an input terminal of an inlet wire filtering loop, and an output terminal of the inlet wire filtering loop is connected with an input terminal of a rectification loop via a reactance coil. An output terminal of the rectification loop is connected with an input terminal of an inversion loop via a capacitor. An output terminal of the inversion loop is connected with an input terminal of an outlet wire filtering loop. An output vacuum contactor is arranged on an output terminal of the outlet wire filtering loop. The system can be widely used for variable-frequency speed regulation of scraper plate machines.