JPS59175104A - Ac electromagnet - Google Patents

Abstract

PURPOSE:To obtain an AC electromagnet with no core noise, small input consumption and small closing impact by a method wherein a rectified voltage of the full voltage is applied to the coil when the electromagnet is closed and after the attraction a reactor is inserted before a rectifier by opening a normally closed type contact. CONSTITUTION:When a switch 8 is closed, an operating coil 4 is excited and a movable core 1 is attracted by a fixed core 2. After the attraction, the inductance becomes large and the current applied to the operating coil 4 becomes small and at the same time the phase difference between flux phi1 and flux phi2 is produced by a shading coil 3 and the attraction is maintained. However, as the shading coil is necessary, AC is rectified to drive the magnet. The large magnetomotive force at the time of closing and the maintaining current after the attraction can not be balanced by the rectification only. Therefore, a normally closed type contact 12 is opened after the attraction to keep the maintaining current small by a reactor 14.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of an AC electromagnet device using a single-phase AC power source as an operating power source.

FIG. 1 shows the most common type of AC electromagnet device using a conventional single-phase AC power source as an operating power source, in which a single-phase AC voltage is directly applied to an operating coil.

In Fig. 1, (11 is a movable core, and (2) is a fixed core.

(31 is the above fixed iron core (
2) is the shade removal coil attached to , (4) is the operation coil that generates magnetic flux, and (5) is the shade removal coil (3).
(6) is the non-shading part outside the shade coil (31), φ1 is the non-shading part (
6) Magnetic flux passing through the non-shaded part, φ2 is the shaded part (5
), G is the air gap between the movable core (11) and the fixed core (2).

The connection of this device is shown in Figure 2, and the voltage vector diagram is shown in Figure 3.
As shown in the figure.

In FIGS. 2 and 3, (7) is the single-phase AC power supply, (8) is the switch, and ■ is the voltage of the single-phase AC power supply (7).

R1 is the internal resistance of the operating coil (4), ω is the angular frequency of the single-phase AC power supply (7), L(t) is the inductance of the operating coil (4), and 1(t) is the current flowing through the operating coil (4). be.

In the conventional electromagnetic device shown in FIGS. 1 and 2, when the switch (8) is closed, the operating coil (4) is energized.
The movable core (1) is attracted to the fixed core (2).

In general, when the air gap G in an AC electromagnet is large, the inductance L (t) in Fig. 3 is small, a large rush current flows through the operating coil (4), and a large attraction force can be generated compared to a DC electromagnet. And the movable iron core (11
When the fixed core (2) completes suction and closes, the inductance L (tl) increases, and the current 1 (t) flowing through the operating coil (4) decreases.At this time, the darkening coil (3) Take part magnetic flux φ2.

A phase difference is created between the magnetic fluxes φ1 of the non-shaded portions, the attractive force of the electromagnet never becomes zero, and the electromagnet maintains the attracted state. It is no exaggeration to say that the success or failure of this conventional electromagnetic device depends on how large the minimum value of the attractive force is designed to be.

FIG. 4(a) shows a waveform of the terminal voltage applied to the operating coil (4) from the start of suction, and FIG. 4(b) shows a change curve of the suction force. No matter how optimally this electromagnetic device was designed, pulsations in the attraction force could not be avoided, and noise from the iron core was a major problem. Since the initial suction force is relatively large, the suction time can be shortened (3), but the injection impact is large, which poses a major problem in terms of lifespan and adverse effects on other mechanical parts. Furthermore.

Because the magnetic flux passing through the iron core alternates, hysteresis loss within the iron core and loss due to the current flowing in the shade coil (31) are generated.
＜The loss of talent was unavoidable, and the consumption input in the adsorption state was by no means small. In addition, in terms of materials and structure, it was necessary to use a laminated core made of expensive silicon steel plates in order to reduce hysteresis loss, and the production of the cut-out coil device also required a great deal of technology.

To address these problems, a DC operated device as shown in FIG. 5 and a DC operated device using a saving resistor as shown in FIG. 6 have been proposed.

Next, the apparatus shown in FIGS. 5 and 6 will be explained. That is, in FIGS. 5 and 6, (9) is a full-wave rectifier, α
[is an operation coil for direct current operation with full voltage applied.

aη is the operating coil for direct current operation where full voltage is applied only when turning on, and voltage divided by the resistance is applied after adsorption, 02 is a normally closed contact for switching between when turning on and after adsorption, and αj is the operating coil after adsorption (11 ) It is a saving resistor to reduce the voltage applied to the consumer (4) and save power.

In the conventional device shown in FIG. 5, since there is no alternating magnetic flux, there is no hysteresis loss in the iron core, and there is no need for a shade removal coil. However, a large magnetomotive force is required at the time of injection,
If a rush current similar to that shown in FIGS. 1 and 2 is applied, this current will continue to flow even after adsorption, and the copper loss in the coil will be too large, causing the coil to burn out if used for a long time. Therefore, in order to limit the current and generate magnetomotive force, a very large number of turns is required, and the operation coil α becomes a large coil. As the coil itself becomes larger, the input power consumed after attraction generally becomes considerably larger than that of the AC electromagnet device shown in FIG.

Moreover, in FIG. 6, in order to prevent the coil from becoming large in the apparatus shown in FIG. 5, and to reduce the input after suction, the normally closed contact Q3 is used to switch between the time of application and the time after suction.

However, even in this case, a considerable amount of Joule heat is generated when the saving resistance is zero, and even after adsorption, the consumed input cannot be said to be small. And because the Joule heat generation in the saving resistor OJ is large, 1
The saving resistor α3 has the disadvantage of being a large resistor with a large allowable input.

The operating coil of the electromagnet device shown in Figures 5 and 6 (1010B
Figures 1 and 8 show the voltage waveforms applied to both ends of the cap and the temporal changes from when the attraction force is applied.

This invention was made in order to solve the above-mentioned drawbacks of the conventional products.When the coil is turned on, a rectified voltage is applied directly to the coil, and the normally closed contact is opened after or just before the adsorption. .

A reactor is connected in series in front of the rectifier, and by utilizing the voltage drop caused by this reactor, the purpose is to provide an inexpensive AC electromagnet device that has no iron core noise, low power consumption, and small input shock. That is.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 9 is a diagram showing an embodiment of the present invention, and FIG. 10 is a vector diagram thereof. That is, in Figure 9, (14
1 beam axle, its inductance is L. a
9 is an operating coil, and when the operating coil θ9 is turned on, the normally closed contact a2 is conductive, and the full voltage is applied.
After adsorption or just before adsorption, the normally closed contact 0z is opened and a voltage divided by the reactor 0z is applied. In addition, in Fig. 10, ■ is the single-phase AC power supply voltage, Ri is the internal resistance of the operating coil 0 [with], and 1
1 is the closing current that flows when the reactor 0g is short-circuited due to the normally closed contact 0 being crossed, and 12 is the closing current that flows when the normally closed contact 02 is opened and the reactor I and the operating coil 0!1
9 is the holding current flowing through the circuit according to 9.

The deviation of this embodiment device is as shown in FIG.

At the time of closing, a large closing current 11 determined only by the internal resistance R1 of the operating coil θ9 flows, ensuring the necessary magnetomotive force at the time of closing. Also, when holding, the beam acdle I and the internal resistance R
A small holding current 12 determined by 1 flows to hold the core. At this time, the magnetic flux flowing through the iron core does not alternate;
In addition, since the rectifier (9) forms a flywheel circuit, there is no noise from the iron core.5Therefore, there is no need to stack the iron cores.

Inexpensive iron plates, cast steel, formed steel, etc. can be used, and there is no need for a shade coil, and hysteresis (7) loss and shade coil loss are also eliminated. Since the voltage is dropped by reactor 0→, the operating coil (151
The input consumed by is very small.

Furthermore, since the input consumption of the reactor a4) is small, the total input consumption during holding is extremely small.

In addition, although the case where it was applied to a shaded coil type electromagnet device was described above, the present invention can be applied to AC electromagnet devices in many fields such as other electromagnetic contactors, electromagnetic relays, and timers.

In the above case, the normally closed contact is opened after or just before the fixed core and movable core are attracted.

This has the advantage of being able to reliably prevent the chattering phenomenon that occurs between the fixed iron core and the movable iron core, and also to prevent noise.

As described above, according to the present invention, since the single-phase AC power supply is once full-wave rectified, the impact upon turning on is alleviated, and iron core noise is completely eliminated. In addition, since a reactor is used to reduce voltage drop and input during holding, input consumption is drastically reduced.
Cheap iron core materials (8) can also be used for the iron core, there is no need for a rounded coil, hysteresis loss and rounded coil loss are eliminated, and an inexpensive and high-performance AC X magnet device can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional single-phase AC electromagnet device. Figure 2 is its circuit diagram, Figure 3 is a voltage vector diagram of the device shown in Figures 1 and 2, and Figure 4 is the operating coil terminal voltage and attraction force of the device shown in Figures 1 and 2. Figures 5 and 6 are circuit diagrams of other conventional devices, respectively, and Figures 7 and 8 are operation diagrams of the devices shown in Figures 5 and 6, respectively. FIG. 9 is a diagram showing the coil terminal voltage and the temporal change from the time when the attraction force is applied. FIG. 9 is a circuit diagram showing an embodiment of the present invention. FIG. 10 is a voltage vector diagram of the device shown in FIG. 9. In the figure, fil is a movable iron core, (2) is a fixed iron core, (3) is a shaded coil, +41. θl, (Ill, α9 is the operating coil, (7) is the single-phase AC power supply, (9) is the full-wave rectifier, and a2 is the normally closed contact. 06 is the accelerator. Note that the same or equivalent parts in Figure 1 The same reference numerals are given. Agent Shin Kuzuno - (10) Figure 1 Figure 2 Figure 7 Figure 8 Figure 9 Figure 10 Figure 1

Claims (1)

[Scope of Claims] (Single-phase full-wave rectifier connected to a single-phase AC power supply through a parallel connection between the 11IJ axle and a contact that is normally closed and becomes open after attracting the movable core of the electromagnet device; An AC electromagnet device comprising an operating coil of an electromagnet device connected to the DC side of a single-phase full-wave rectifier. (2) A patent claim characterized in that a shaded coil type electromagnet device is used as the electromagnet device. (3) The AC electromagnet according to claim 11 or (2), characterized in that the reactor uses an electric wire wound around a fixed iron core. Device.