Alarm capable of performing alarming automatically in switching off circuit

Abstract

The invention discloses an alarm capable of performing alarming automatically in switching off a circuit. The alarm comprises a hollow housing. The alarm is characterized in that the housing is provided with a loudspeaker; the housing is internally provided with a protector, an AC contactor, a DC level device and a power amplifier, wherein the protector, the AC contactor, the DC level device and the power amplifier are successively connected; the sidewall of the housing is provided with a through hole; a lead on the protector is connected with a plug outside the housing through the through hole; and the power amplifier is connected with the loudspeaker. The alarm is connected with a main circuit. In a normal condition, the AC contactor switches off the DC level device and the loudspeaker does not perform alarming. When a front circuit is off, the AC contactor switches on the inner loop of the DC level device, and DC power which is generated by the DC level device makes the loudspeaker perform alarming. The circuit of the alarm does not require man monitoring. Furthermore error alarming of the alarm is prevented.

Description

technical field [0001] The invention relates to an alarm that can automatically alarm when the circuit is cut off. Background technique [0002] Accidents of transformers and cables being stolen happen from time to time, which will cause great losses to production and life. At present, the method of detecting the resistance balance of the circuit or the voltage balance at the end of the power supply line is often used to judge the state of the line, but this method has the following disadvantages, and special personnel are required to check the operation of the circuit. [0003] However, the switching line resistance of the electric load often changes, and the terminal voltage balance is often broken by the unbalanced line load, which is prone to false alarms. Therefore, the above-mentioned method for judging the line state is inconvenient and unreliable. Contents of the invention [0004] In order to solve the above existing shortcomings, the main purpose of the present ...

AI Technical Summary

Problems solved by technology

[0002] Accidents of transformers and cables being stolen happen from time to time, which will cause great losses to production and life

At present, the method of detecting the resistance balance of the circuit or the voltage balance at the end of the power supply line is often used to judge the state of the line, but this method has the following disadvantages, and special personnel are required to check the operation of the circuit

[0003] However, the switching line resistance of the electric load often changes, and the terminal voltage balance is often broken by the unbalanced line load, which is prone to false alarms. Therefore, the above method of judging the line status is inconvenient and unreliable.

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