JPS63307710A - Alternating current electromagnet device - Google Patents

Abstract

PURPOSE:To contrive reduction in electromagnet noise by a method wherein a constant current diode is series-connected to a coil. CONSTITUTION:Constant-current diodes 6A and 6B constitute a series-connected body in which two constant-current diodes having different polarity with each other are series-connected, and they are series-connected to a coil 3. When a switch 5 is closed, a current is applied to the coil 3, and the current is made to flow in the direction shown by the arrow in the diagram when the output terminal 4A of a single phase AC power source 4 is positive. When the output terminal 4A is positive, the constant-current diode 6B does not show constant- current characteristics in a conductive state, but the constant-current diode 6A shows constant-current characteristics. Accordingly, current waveform shows an almost rectangular waveform. As a result, electromagnetic noise can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an AC electromagnet device that attracts a movable iron core, for example.

[Conventional technology]

FIG. 3 is a partially sectional front view of a conventional AC electromagnet device disclosed in, for example, Japanese Patent Application Laid-Open No. 59-029408.

In Fig. 3, (1) is a movable core, and (2) is a fixed core.

(31 is a coil, for example, an operating coil. Figure 4 is a circuit diagram in which the operating coil (3) of the device shown in Figure 3 is connected to a single-phase AC power supply (4), and (5) is a switch. be.

In the figure, G indicates a gap between the fixed iron core (21) and the movable iron core (1).

In the AC electromagnet device having the above configuration, when the switch (5) is closed, the operation coil (3) is excited. This excitation excites the iron core (11, +21), and the movable iron core (11) is attracted to the fixed iron core (2). Here, the AC electromagnet is.

When the air gap G shown in FIG. 3 is large, the inductance of the operation coil (31) is small, so a large rush current flows through the operation coil (3), and it is possible to generate a large attraction force compared to a DC electromagnet. , movable iron core (1
1 adsorbs to the fixed iron core (2) and closes.

The inductance increases, and the current flowing through the operating coil (31) decreases.

When the switch (5) is opened to cut off the coil current, the movable iron core (1) is separated from the fixed iron core (2) by a spring (not shown).

FIG. 5 is a waveform diagram showing the waveform of the coil current, where the horizontal axis shows time and the vertical axis shows current.

[Problem that the invention seeks to solve]

Conventional AC electromagnet devices are constructed as described above and operate at ℃, but since the coil current is sinusoidal AC as shown in Figure 5, the pulsation of the attractive force is large, resulting in large electromagnetic noise. There was a problem.

This invention was made to solve the above-mentioned problems, and an object thereof is to obtain an AC electromagnet device with low electromagnetic noise.

[Means for solving problems]

The AC electromagnet device according to the present invention has a fixed iron core.

This AC electromagnet device includes a movable core that is attracted to the fixed core, and a coil that excites the core, and is connected in series with a constant current diode t-coil.

[Effect]

The AC electromagnet device of the present invention reduces the electromagnetic noise of the AC electromagnet by reducing the peak value of the coil current.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (6 people) and (6B) are constant current diodes, and the others are the same as or equivalent to those in FIG. 4. The constant current diodes (6A) and (6B) constitute a series connection body in which two constant current diodes with opposite polarities are connected in series, and are connected in series with the coil (3). This constant current diode (6A)? (6B) is 2 e.g. magazine (Transistor Technology SPgCIAL).

1986, Chapter 4, Constant Current Diodes, pages 42 to 45) is used.

Further, the characteristic is such that it is suppressed to about 0.6 times the peak value of the sinusoidal current, for example.

In Figure 1, when the switch (5) is closed, the coil (3)
) is supplied with current. When the output terminals (4) of the single-phase AC power supply (4) are positive, current flows in the direction of arrow X shown in FIG. When the output terminals (4) are positive, the constant current diode (6B) is in a conductive state and does not exhibit constant current characteristics, but the constant current diode (c) exhibits constant current characteristics.

Next, when the output terminal (4B) of the single-phase AC power supply (4) is positive, the current flows in the direction of arrow Y shown in FIG.

When the output terminal (4B) is positive, the constant current diode (6A
) does not exhibit constant current characteristics in a conductive state, but constant current diode (6B) exhibits constant current characteristics.

Therefore, as shown in FIG. 2, the current waveform has a current peak value approximately 0.6 times that of the conventional one, and exhibits a substantially rectangular waveform. Therefore, in this embodiment, since a rectangular current flows, the current peak value is low, and an average attraction force equal to or comparable to that of the conventional electromagnet shown in FIGS. 3 and 4 can be obtained. According to this embodiment, the maximum attraction force of the electromagnetic device is lower than that of the conventional one.

It was confirmed that the electromagnetic noise was low.

In the embodiment shown in Fig. 1, two constant current diodes (6A) and (6B) with opposite polarities are connected in series.
It is obvious that electromagnetic noise can be reduced even if one constant current diode is connected in series with the coil.

Furthermore, if the maximum operating voltage of the constant current diode is low in FIG. 1, a series connection of constant current diodes with the same polarity may be used.

Also, if the maximum operating current of the constant current diode is low,
A parallel connection of constant current diodes with the same polarity can be used.

〔Effect of the invention〕 As described above, according to the present invention, a fixed iron core is provided.

In an AC electromagnet device that includes a movable core that is attracted to the fixed core and a coil that excites the core, the AC electromagnet device that can reduce electromagnetic noise can be obtained by connecting a constant current diode in series with the coil. be.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a circuit of an AC electromagnet device according to an embodiment of the present invention, FIG. 2 is a waveform diagram showing changes in coil current over time according to an embodiment of the present invention, and FIG. FIG. 4 is a circuit diagram showing circuit Y of the conventional device; FIG. 5 is a waveform diagram showing changes in coil current over time of the conventional device. In the figure, (11 is a movable core, (21 is a fixed core, (
3) is a coil, and (c) and (6B) are constant current diodes. In the figures, the same reference numerals indicate the same or equivalent parts.

Claims (2)

[Claims] (1) A fixed core, a movable core that is attracted to this fixed core,
and an AC electromagnet device comprising a coil for exciting the iron core, characterized in that a constant current diode is connected in series with the coil. (2) The AC electromagnet device according to claim 1, wherein the constant current diode is a series connection of constant current diodes with opposite polarities.