JPS6236368B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention aims to reduce iron core noise, save power consumption, and
This relates to improvements such as reduction of input shock.

FIG. 1 shows a schematic diagram of the most common AC electromagnet device that uses a conventional single-phase AC power source as an operating power source. In Fig. 1, 1 is a movable core, 2 is a fixed core, and 3 is a movable core.
is a shading coil (hereinafter referred to as Kumatori coil) installed to eliminate the zero point of electromagnetic attraction force, 4 is an operating coil that generates magnetic flux, and 5 is Kumatori coil 3
6 is the non-kumatori part outside the Kumatori coil 3, _φ1 is the non-kumatori magnetic flux passing through the non-kumatori part 6, and _φ2 is the Kumatori part magnetic flux passing inside the Kumatori part 5. , G(t) is the gap between the movable core 1 and the fixed core 2. The connections of this device are shown in FIG. Moreover, the voltage vector diagram is shown in FIG. In Figures 2 and 3, 7 is a single-phase AC power supply, 8 is a switch, V is the voltage vector of the single-phase AC power supply 7, _R1 is the internal resistance of the operating coil 4, and ω is the single-phase AC power supply. The angular frequency of the power source 7, L(t) is the inductance of the operating coil 4, and i(t) is the inductance of the operating coil 4.
is the current flowing through.

In FIG. 2, when the switch 8 is closed, the operating coil MC4 is energized and the movable core 1 is pulled in the direction of the arrow in FIG. In general, when the air gap G(t) of an AC electromagnet is large, the inductance L(t) shown in Fig. 3 is small, a large lash current flows through the exciting coil 4, and a large attractive force can be generated compared to a DC electromagnet. . When the movable iron core 1 and the fixed iron core 2 complete attraction and close, the inductance L(t) increases and the current i(t) flowing through the exciting coil 4 decreases. At this time, a phase difference is created between the magnetic flux 2 in the magnetic area ₂ and the magnetic flux ₁ in the non-magnetic area due to the magnetic flux coil 3, so that the attractive force of the electromagnet does not become zero, and the electromagnet maintains the attracted state. It is no exaggeration to say that the success or failure of this conventional electromagnetic device depended on how large the minimum value of the attractive force was designed to be.

FIG. 4 shows a relationship diagram (a) between the inter-terminal voltage v applied to the excitation coil 4 from the start of attraction and time t, and a relationship diagram (b) between attraction force f and time, respectively, as curves. Note that P indicates the time point when the iron core is closed. No matter how optimally designed this electromagnetic device was, pulsations in the attraction force were unavoidable, and noise from the iron core was a major problem. Since the initial suction force is relatively large, the suction time can be shortened, but the injection impact is large, which poses a major problem in terms of lifespan and adverse effects on other parts and mechanical parts. Furthermore, since the magnetic flux passing through the iron core alternates, hysteresis loss within the iron core and loss due to current flowing through the magnetic coil 3 are unavoidable, and the power consumption in the attracted state is by no means small. In terms of materials and structure, in order to reduce hysteresis loss, it was necessary to use a laminated core made of expensive silicon steel plates, and the sophistication of technology that could not be ignored was also required for Kumatori coils.

In order to deal with these problems, there have conventionally been methods for direct current operation as shown in FIG. 5 and methods for direct current operation using a saving resistor 13 as shown in FIG.

9 is a full-wave rectifier, 10 is an operation coil for DC operation that applies full voltage, 11 is an operation coil for DC operation that applies full voltage only when it is turned on, and after adsorption, a voltage divided by a resistor is applied, and 12 is an operation coil that is used when it is turned on. A normally closed contact 13 is used to switch between post-adsorption and post-adsorption, and a saving resistor R is used to lower the voltage applied to the operation coil 11 after adsorption to save input power. In FIG. 5, since there is no alternating magnetic flux, there is no hysteresis loss in the iron core, and no kumatori coil is required. However, since a large magnetomotive force is required at the time of insertion, if a lash current similar to that shown in Figure 2 is applied, this current will continue to flow even after attraction.
Copper loss in the coil is too large, and the coil will burn out if used for a long time. Therefore, in order to limit the current and generate magnetomotive force, a very large number of windings are required, and the operating coil 10 becomes a large coil. As the coil itself becomes larger, the power consumption after attraction generally becomes considerably larger than that of the AC electromagnet device shown in FIG. In Figure 6, the 5th
In the figure, in order to prevent the coil from increasing in size and to reduce the input after suction, a normally closed contact 12 is used to switch between when it is turned on and after suction. However, even in this case, a considerable amount of copper loss occurs in the saving resistor R13, and the consumed input cannot be said to be small even after adsorption. Since this copper loss is large, the saving resistor R13 is often a large resistor with a large allowable input.

Operating coil 1 of the electromagnet device shown in Figs. 5 and 6
The voltage waveform v applied to both ends of 0 and 11 and the temporal change from the time of application of the attractive force f are shown in Fig. 7 a and b, respectively.
and shown in FIGS. 8a and 8b. Note that the time point when the normally closed contact 12 is opened (off) is shown.

This invention was made in order to solve and eliminate the problems and drawbacks of the conventional ones as described above.When the voltage is turned on, a half-wave rectified voltage is applied to the second operating coil, and after or just before the core is attracted, the normally closed contact is By turning it open (OFF), a DC component of the suction force is created by induction from the first operating coil installed on the AC side to the second operating coil and the flywheel effect, resulting in no iron core noise, low power consumption, and even less impact when starting. The purpose of the present invention is to provide an AC electromagnet device that has a low cost and is low in cost.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 9 is a circuit diagram showing an embodiment of the circuit according to the present invention, and FIGS. 10a, b, and c show the terminal voltages of the first and second operating coils when the circuit of FIG. 9 is used. The graph shows the progress of v ₁ , v ₂ and the attraction force f based on these values over time t. In Fig. 9, 7 is an AC power supply, 8 is an on/off switch, and 12
is a normally closed operating point, 14 is a first rectifier, 15 is a second rectifier, 16 is a first operating coil, and 17 is a second operating coil. Note that the normally closed contact 12, the first rectifier 14, and the second operating coil 17 constitute a series connection body, and are connected in parallel to the first operating coil 16. When the second operation coil (MC ₂ ) 17 is turned on, the normally closed contact 12 is conductive and a single-phase half-wave voltage is applied, but after or just before the attraction, the normally closed contact 12 is opened and the first operating coil 16
This is the second operating coil that generates the voltage necessary to flow the holding current by induction from the coil. Reference numeral 16 denotes a first operating coil that is guided to a second operating coil 17 by applying an AC voltage after attraction. Note that the first operating coil 16 and the second operating coil 17 are provided in the same magnetic path, and are wound twice around the same coil spool, for example.

i is the second operating coil MC ₂ 17 and the second rectifier
This is the current flowing through the loop with D ₂ 15. At the time of closing, a large closing current determined mostly by the internal resistance of the second operating coil MC ₂ 17 flows through the second operating coil MC ₂ 17 to ensure the necessary magnetomotive force at the time of closing. At the time of holding, the first operating coil MC ₁
16 to the second operating coil MC ₂ 1 by electromagnetic induction.
An induced voltage is generated at 7. And the second rectifier
A flywheel circuit is formed by D ₂ 15 and the second operating coil MC ₂ 17, and due to the flywheel effect shown in FIG.
A current of i flows through the MC ₂ 17, and the magnetic flux that passes through the iron core is mainly a direct current component. For this purpose, a second operating coil MC ₂ is provided in the same magnetic path.
Since the current is reduced by a half wave in No. 17, the input becomes small and the size of the coil can be made small. In addition, since the core magnetic flux has a pulsating waveform mainly composed of flow, core noise is almost non-existent. It goes without saying that if the connection direction of the first rectifier 14 and the second rectifier 15 is opposite to the direction shown in FIG. 9, they will operate in the same way.

As described above, according to the present invention, since the single-phase AC power source is once half-wave rectified, the impact when it is turned on is greatly reduced. Furthermore, since the core magnetic flux has a pulsating waveform mainly composed of DC components, core noise is almost non-existent.

During holding, an induced voltage is generated by electromagnetic induction from the first operating coil MC ₁ 16 to the second operating coil MC ₂ 17 to form a flywheel circuit, and the first operating coil MC ₁ 16 is Since the number of turns is so small that it cannot be attracted or held by voltage, the exciting current is very small.
Therefore, the input power consumption of the coil can be reduced, and since the circuit is composed of only the rectifier and the coil, it is possible to obtain an AC electromagnet device that is inexpensive, highly reliable, and has high performance.

INDUSTRIAL APPLICATION This invention can be utilized for the electromagnet drive device of many fields, such as an electromagnetic contactor, an electromagnetic relay, and a timer.

In addition, it is possible to connect a capacitor or a resistor to both ends of a normally closed contact, convert the normally closed contact into a semiconductor, or
Applications such as converting the rectifier shown in the figure into a thyristor can also be easily realized.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the main parts of a conventional AC electromagnet device, Figure 2 is its circuit diagram, Figure 3 is a voltage vector diagram in the circuit, and Figure 4 is voltage v vs. time t and attractive force f vs. Characteristic diagrams a and b showing the passage of time t, FIGS. 5 and 6 are examples of circuit diagrams of a conventional electromagnetic device for improving the device shown in FIG. 1, and FIGS.
The figures show the relationship a between the voltage between the terminals of the operating coil v and time t, and the relationship b with time t from the time when the attraction force f is applied, in the circuits corresponding to FIGS. 5 and 6, respectively. 9 is a circuit diagram of an embodiment of an AC electromagnet device according to the present invention, and FIG.
The figure is a temporal change diagram a of the voltage between the terminals of the first operating coil v ₁ and the time t from the time of application in this embodiment,
A diagram b showing a temporal change in the voltage between the terminals of the second operating coil v ₂ from the time of application, and a diagram c a diagram c in which the attraction force f changes over time. In each figure, 1 is a movable core, 2 is a fixed core,
3 is a shading coil, 4 is an operating coil, 5 is a closed section, 6 is a non-closed section, 7 is an AC power supply, 8 is a switch, 9 is a rectifier, 10 is an operating coil, 11 is an operating coil, 12 is normally closed Contact point, 13 is a saving resistor,
14 is a first rectifier, 15 is a second rectifier, 16
17 is a first operating coil, and 17 is a second operating coil. In addition, G(t) is the width of the air gap, φ ₁ and φ ₂ are the magnetic flux, MC is the operating coil, V is the voltage vector, and R ₁
is the internal resistance of the coil, i(t) is the current, ω is the angular frequency, L(t) is the inductance of the coil, v is the voltage between the terminals of the coil, t is time, f is the attractive force, p
is when the iron core is closed, Q is when the normally closed contact is turned off, D ₁ ,
D ₂ is the first and second rectifier, MC ₁ and MC ₂ are the first operating coil and second operating coil, respectively, and v ₁ and v ₂ are the voltages between the terminals of the first and second operating coils, respectively. In each figure, the same reference numerals represent the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. In an AC electromagnet device using a single-phase AC power source as an operating power source, a first operating coil connected to both ends of the single-phase AC power source, and a first operating coil connected in parallel to the first operating coil. a series connection body consisting of a normally closed contact, a first rectifier and a second operating coil;
A second rectifier is connected in parallel to the operating coil of the electromagnetic device, and the second rectifier is connected with the same polarity as the first rectifier. The first operating coil and the second operating coil are provided in the same magnetic path of the electromagnetic device, and the first operating coil cannot attract or hold at the rated voltage. and the second operating coil generates a voltage necessary to flow a holding current by induction from the first operating coil after the normally closed contact is opened. AC electromagnet device. 2. The AC electromagnet device according to claim 1, wherein the first operating coil and the second operating coil are wound twice on a spool of the same coil.