JPS6021865Y2 - Electric contact interference radio wave prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an interference radio wave prevention device for preventing interference radio waves due to arc noise generated from the contacts of a switch having electrical contacts.

Generally, electrical contacts include a two-position switch as shown in Figure 2a, a relay as shown in Figure 2, and a rotary switch as shown in Figure 2C, but these electrical contacts are a source of noise. .

Therefore, in the past, power line filters for preventing interference radio waves have been used as interference radio wave prevention devices in electrical equipment including electrical contacts.

These filters include, for example, one three-phase prevention capacitor, or eight oil tubular capacitors, ceramic capacitors, W capacitors, etc., between the power line 11 of the electrical equipment 10 that is the source of noise, as shown in Figure 1. Interference radio wave prevention device 12 including a combination of individual devices
There is.

In this conventional interference radio wave prevention device 12, circuit assembly work such as parts and soldering and screwing increases and becomes complicated, workability decreases and becomes expensive, and the circuit itself becomes large and complicated. There were various drawbacks, such as a large number of electrical disturbances occurring due to this, which reduced the noise prevention effect.

The present invention eliminates the above-mentioned drawbacks, provides a device for preventing interference radio waves of electrical contacts, which can be made simple, inexpensive, and compact, has improved workability, and has extremely large attenuation characteristics.

Hereinafter, one implementation of the present invention will be explained based on FIG. 3.

Note that this embodiment relates to the case of the relay 4 shown in FIG.

In the figure, 1 is a reactance element, 2 and 3 are capacitance elements, and Ll and L2 are loads.

The reactance element 1 is selected to have a value of 0 to 200 μH, and the +pasitance elements 2 and 3 are selected to have a value of 0.01 to 0.5 μF.

The reason for this is that the reactance element 1 has poor noise attenuation characteristics with respect to noise on the low frequency side when the reactance element 1 is 10 μH or less.

Moreover, if it is 200 μH or more, the distributed capacitance of the reactance element 1 increases and its noise attenuation characteristics deteriorate.

Similarly, in capacitance elements 2 and 3, 0.011
Below LF, the noise attenuation characteristics are poor for noise on the low frequency side.

Moreover, if it is 0.5 μF or more, the distributed reactor capacitance of the capacitance elements 2 and 3 increases, resulting in poor noise attenuation characteristics.

As described above, capacitance element 2. 3Li0.01
~0.5 μF is desirable.

Further, the reactance element 1 can obtain good results at 10 to 200 ILH.

Now, if the reverse contact NC of the relay 4 were to open, noise would be generated due to the arc.

However, a series circuit of an actance element 1 and a capacitance element 3 is connected in parallel to this reverse contact NC to ensure that the noise is attenuated.

Also, noise is generated when the tangent contact NO closes.

Similarly, a series circuit of a reactance element 1 and a capacitance element 2 is connected in parallel to the tangent point No, so that noise is reliably attenuated.

In this way, the reactance element 1 is commonly used to attenuate the noise generated from the positive contact NO and the negative contact NC.

It goes without saying that the apparatus for preventing interference radio waves for electrical contacts of the present invention can also be applied to other electrical contacts such as two-position switches and rotary type switches shown in FIGS. 2a and 2c.

According to the above-described interference radio wave prevention device for electrical contacts of the present invention, one end of a reactance element is connected to a common contact of a switch, one end of a capacitance element is connected to a contact other than the common contact of the switch, and the reactance Because the other end of the element and the other end of the capacitance element are commonly connected, the series circuit of the actance element and the capacitance element will be connected to the reverse contact NC and the positive contact No in the event of excessive fluctuations in switch switching, which may cause interference radio waves. Possible noise is reliably attenuated by this series circuit, resulting in extremely large noise attenuation characteristics compared to conventional power line filters.

Moreover, one actance element can be used in common for the reverse contact NC and the positive contact NO.

Furthermore, since the circuit is simple, the noise prevention effect due to line impedance is not reduced, and it has great industrial value.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional power line filter, FIGS. 2a, b, and c are circuit diagrams of various electrical contacts, and FIG. 3 is a circuit diagram showing an embodiment of the present invention. 1... Reactance element, 2, 3...
Capacitance element, 4... Relay, 11...
・・・・Power line, No. ・・Positive contact, NC・
...Reverse contact.

Claims (1)

[Scope of utility model registration request] One end of a reactance is connected to a common contact of a switch having electrical contacts, one end of a capacitance element is connected to a contact other than the common contact, and the other ends of the reactance element and the capacitance element are all connected in common. An interference radio wave prevention device for electrical contacts.