Anti-electric shock discharge circuit

Abstract

An anti-electric shock discharge circuit is electrically connected to a power conversion device that converts input AC power into high-voltage DC voltage and outputs it through its positive and negative terminals. The anti-electric shock discharge circuit includes a discharge resistor and an electromagnetic contactor. The electromagnetic contactor comprises a switching unit, a normally closed switch, a control switching unit, and an electromagnet that actuates the normally closed switch. The switching unit controls whether AC power is input to the power conversion device. One end of the normally closed switch is connected to one of the positive and negative terminals, and the other end of the normally closed switch is connected to one end of the discharge resistor, and the other end of the discharge resistor is connected to the other of the positive and negative terminals. When the electromagnet is powered, it controls the switching unit to allow AC power input to the power conversion device and controls the normally closed switch to be off-circuit. When the electromagnet is not powered, it controls the switching unit to prevent AC power input to the power conversion device and controls the normally closed switch to be on, forming a discharge loop from the positive terminal, the normally closed switch, the discharge resistor, to the negative terminal.

Claims

1. An anti-electric shock discharge circuit, electrically connected to a power conversion device, the power conversion device converting an input AC power supply into a high-voltage DC voltage and outputting it to a load device through a positive terminal and a negative terminal; the anti-electric shock discharge circuit includes: One discharge resistor; An electromagnetic contactor includes a switching unit, a normally closed switch, and an electromagnet that controls the operation of the switching unit and the normally closed switch. The switching unit receives the AC power and is connected to a power input terminal of the power conversion device to control whether the AC power is input to the power input terminal. One end of the normally closed switch is electrically connected to one of the positive terminal and the negative terminal, and the other end of the normally closed switch is electrically connected to one end of a discharge resistor, and the other end of the discharge resistor is electrically connected to the other of the positive terminal and the negative terminal. When the electromagnet is powered, the electromagnet controls the switching unit to conduct, allowing the AC power to be input to the power input terminal, and controls the normally closed switch to switch from conducting to non-conducting. When the electromagnet is not powered, the electromagnet controls the switching unit to de-conduct, preventing the AC power from being input to the power input terminal, and controls the normally closed switch to switch from non-conducting to conducting, thereby forming a discharge circuit from the positive terminal, the normally closed switch, the discharge resistor to the negative terminal.

2. The anti-electric discharge circuit as described in claim 1, wherein, The electromagnetic contactor also includes a normally open switch controlled by the electromagnet. One end of the electromagnet is electrically connected to a power switch, and the other end of the electromagnet is electrically connected to a neutral point of the AC power supply. One end of the normally open switch is electrically connected to one phase of the three-phase AC power supply, and the other end of the normally open switch is electrically connected to the power switch. When the power switch is operated to an open state, the power switch temporarily allows the phase power to flow through the power switch, the electromagnet, and the neutral point to energize the electromagnet, causing the electromagnet to control the normally open switch to switch from non-conducting to conducting, so that the phase power flows through the normally open switch, the power switch, the electromagnet, and the neutral point to continuously supply power to the electromagnet. When the power switch is operated to a closed state, the power switch temporarily prevents the phase power from supplying power to the electromagnet through the power switch, so that the electromagnet is demagnetized and controls the normally open switch to switch from conducting to non-conducting, thereby preventing the phase power from supplying power to the electromagnet.

3. The anti-electric discharge circuit as described in claim 2, wherein, The three-phase power supply of the AC power supply is first input to a residual current circuit breaker, and is electrically connected to the switching unit of the electromagnetic contactor through the three-phase output terminal of the residual current circuit breaker, so as to output the three-phase power supply to the switching unit through the three-phase output terminal; the neutral point of the AC power supply is electrically connected to a neutral point output terminal of the residual current circuit breaker, and is electrically connected to the other end of the electromagnet through the neutral point output terminal.

4. The anti-electric discharge circuit as described in claim 1, wherein, The discharge resistor is a gold-plated aluminum-cased resistor.

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