JPH0715346Y2 - High frequency noise feedback prevention type electrical equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a high frequency noise feedback prevention type electrical device, and more specifically, a high frequency noise feedback prevention type electrical device capable of reducing high frequency noise returned to an AC side. It is about.

Conventional technology and its problems Power supply devices such as switching regulators, electric devices such as computers and exchanges are mainly composed of electronic circuits that generate high-frequency noise, such as electronic circuits that switch at high speed, using an AC power supply as a drive power source. As a result, extremely high frequency noise is generated on the AC side, which may cause peripheral devices to malfunction. For this reason, it has become an essential condition for these electric devices to pass the FCC standard in the United States that regulates high-frequency noise that returns to the AC side and the VDE standard in West Germany.

In order to suppress such high-frequency noise, there is one in which a noise filter 4 is interposed between an electronic circuit 5 that switches at high speed and an AC power supply 2 as shown in FIG. 4, but the AC power supply is used as a drive power supply. In general, the electric device 1 ′ is provided with a trip circuit 6 for tripping the circuit breaker 3 while the AC power source 2 is applied through the circuit breaker 3 as shown in FIG. However, by providing such a trip circuit 6,
The high frequency noise that returns to the AC side via these increases,
It may not be possible to meet the above standards. Therefore, conventionally, as shown in FIG. 6, the voltage of the trip coil 3-3 of the trip circuit 6 is taken between the noise filter 4 and the electronic circuit 5 which switches at high speed so that high frequency noise is not fed back to the AC side. However, since the trip coil 3-3 and the main contacts 3-1 and 3-2 are built close to each other in the circuit breaker 3, the trip coil 3-3
It was not possible to suppress the high-frequency noise that returns to the AC side via the stray capacitance between the main contacts 3-1 and 3-2.

The purpose of the present invention is to solve the above-mentioned drawbacks, and to suppress the high frequency noise that returns to the AC side via the stray capacitance between the trip coil, the alarm contact, the auxiliary contact and the main contact in the circuit breaker, the high frequency noise is suppressed. The purpose is to provide a non-feedback type electric device.

The high-frequency noise feedback prevention type electric device of the present invention is applied to an electronic circuit that generates high-frequency noise, such as an electronic circuit that switches an AC power supply at high speed through a circuit breaker and a noise filter, and from the electronic circuit. The generated high-frequency noise is suppressed by a common mode choke or reactor so as not to return to the AC side through the trip circuit of the circuit breaker, alarm contact, and auxiliary contact.

Examples Hereinafter, examples will be described. 1 to 3 are block diagrams of an embodiment of a high frequency noise feedback prevention type electric device of the present invention. In FIGS. 1 to 3, elements common to FIGS. 4 to 6 are represented by the same numerals. FIG. 1 shows that high frequency noise generated from the electronic circuit 5 switching at high speed causes trip coil 3-3 of the trip circuit 6 and main contacts 3-1 and 3-2.
The common mode choke 7 is inserted in series with the trip coil 3-3 so as not to return to the alternating current side via the stray capacitance between and. Further, FIG. 2 shows a reactor 8 inserted so that high frequency noise generated from the electronic circuit 5 switching at high speed is not added to the trip circuit 6. Further, FIG. 3 shows a case where the circuit breaker 3 has an auxiliary contact and / or an alarm contact 3-4.
The common mode choke 7 is inserted in the circuit up to 4, and the high frequency noise generated from the electronic circuit 5 switching at high speed causes the stray capacitance between the contact 3-4 and the main contacts 3-1 and 3-2. It does not return to the AC side via the.

In the above, the circuit that generates high frequency noise is not limited to the electronic circuit 5 that switches at high speed.

Effect of the Invention As described in detail in the embodiments, the high-frequency noise feedback prevention type electric device of the present invention can suppress high-frequency noise returning from the electronic circuit that switches at high speed to the AC side through the circuit breaker. It is of extremely high practical value and can pass the FCC standard of Germany and the VDE standard of West Germany.

[Brief description of drawings]

1 to 3 are block diagrams of an embodiment of a high frequency noise feedback prevention type electric device of the present invention, FIGS. 4 and 5 are block diagrams of an electric device using a general AC power source as a driving power source, and FIG. FIG. 1 is a block diagram of a conventional high frequency noise feedback prevention type electric device. 1 …… High frequency noise feedback prevention type electric equipment, 2 …… AC power supply 3 …… Circuit breaker, 4 …… Noise filter 5 …… High-speed switching electronic circuit 6 …… Trip circuit, 7 …… Common mode choke 8 ・ ・ ・… Reactor

Claims (1)

[Scope of utility model registration request] 1. A circuit breaker having one end of a main contact connected to an AC power source side, a noise filter having one end connected to the other end of the main contact of the circuit breaker, and an input side connected to the other end of the noise filter. An electronic circuit for generating high frequency noise, and the circuit breaker has a built-in trip coil which is adjacent to its main contact and excited by a trip signal from the electronic circuit, or by a signal from the electronic circuit. A built-in alarm contact or auxiliary contact that operates, the trip coil is inserted between the power supply lines at the connection points of the circuit breaker and the noise filter, and the alarm contact or auxiliary contact is connected to the signal output line of the electronic circuit. In the high frequency noise feedback prevention type electrical equipment inserted in
A high frequency noise feedback characterized in that a common mode choke is inserted in a power supply line inserted through the trip coil or a signal output line inserted through the alarm contact or auxiliary contact, or a reactor is inserted in the signal output line. Preventive electrical equipment.