Automatic switching power supply circuit used in underground coal mine

Abstract

The invention discloses an automatic switching power supply circuit used in an underground coal mine. The automatic switching power supply circuit solves the problem that misoperation is easily caused when an existing underground double-power-supply circuit switches. The automatic switching power supply circuit is characterized in that a three-phase frequently-used power source (1) is electrically connected with a load (8) through a main contactor, a three-phase standby power source (10) is electrically connected with the load (8) through a standby contactor, a coil (2) of a relay is connected between a C-phase power source and an A-phase power source of the three-phase frequently-used power source (1) in parallel, a normally open auxiliary contact (3) of the relay, a normally closed contact (4) of the standby contactor and a coil (5) of the main contactor are connected in series to be connected between a B-phase power source and the C-phase power source of the three-phase frequently-used power source (1) in parallel, and a normally closed auxiliary contact (11) of the relay, a normally closed contact (12) of the main contactor and a coil (13) of the standby contactor are connected in series to be connected between a B-phase power source and a C-phase power source of the three-phase standby power source (10) in parallel. Automatic and reliable switching between two circuits of underground power sources is achieved.

Description

technical field [0001] The invention relates to an underground lighting circuit, in particular to a three-phase power supply circuit for automatic switching of dual power supplies for underground lighting and control in coal mines. Background technique [0002] In the underground, the lighting and control circuits used in the cavern, working face, monitoring room, intelligent console, etc. are two independent power supply devices, one is the normal power supply and the other is the backup power supply. When the three-phase power grid voltage is unstable or faulty in the common power supply, it is necessary to manually connect these devices to the backup power supply. When the console fails and the power is cut off, all states in the mine will be out of control, which may easily cause underground safety accidents. There are potential safety hazards in manual switching of power supplies, especially the misoperation of switching will cause damage to downhole equipment, especia...

AI Technical Summary

Problems solved by technology

[0003] The invention provides an automatic switching power supply circuit for underground coal mines, which solves the technical problem of safety accidents caused by underground power outages and misoperations caused by manual switching of dual power supplies in underground mines

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