JPS59202613A - Alternative current electromagnet device - Google Patents

Abstract

PURPOSE:To make it titled device smaller in size as well as to contrive improvement in reliability by a method wherein a control coil is divided into a plurality of parts, said plurality of control coils are connected in parallel when a core is attracted, an attraction current is applied on the core, and the coils are series-connected after the core has been attracted, thereby enabling to reduce loss. CONSTITUTION:Both ends of a control circuit are connected to the DC terminal of a full wave rectifier 3 by connecting the control coil 1a, which is one of the splitted-in- two control coils 1a and 1b, to the other control coil 1b in series. A normally closed contact point 6a is connected between the connection point of the control coil 1a and the diode 7, and the full wave rectifier of the control coil 1b, and a normally closed contact point 6b is connected between the connection point of the DC terminal of the full wave rectifier 3 and the control coil 1a and the connection point of the diode 7 and the control coil 1b. When a DC current is applied to the two control coils 1a and 1b, a movable core is attracted to a fixed core. The two normally closed contact points 6a and 6b are opened when the movable coil is attracted or immediately before it is attracted, and two control coils 1a and 1b are series-connected through the intermediary of the diode 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to an AC electromagnet device used in an electromagnetic contactor or the like using a single-phase AC power source as a control power source.

[Prior art and its problems]

Generally, an electromagnetic device used in an electromagnetic contactor, etc. has a fixed core wrapped around an operating coil and a movable core that faces the fixed core with an air gap between them.When the operating coil is energized, the movable core connects to the fixed core by approximately the length of the gap. The moving stroke of the movable core at this time is used as the operating stroke of the contact. By the way, when this electromagnet device is operated with a commonly available single-phase AC power source, when AC current flows through the operating coil, iron loss occurs due to AC magnetic flux in the iron core, so electric iron plates are laminated to reduce this. However, this iron loss cannot be completely eliminated. In addition, in order to maintain the attractive force of the iron core at the current zero point and to reduce the undulation, a shank υ coil is used.
There is a drawback that this loss cannot be ignored, and there is also a drawback that the materials and man-hours required for the use of laminated stones, shaded coils, etc. are high. Furthermore, the control power source for electromagnet devices is AC.

Regardless of direct current, there is always a large gap between the fixed core and the movable core, and the movable core usually carries the load that it must drive, so when the fixed core draws in this, a large ampere turn is required. A large current must be passed through the operating coil. However, once the movable core is attracted, there is almost no air gap, and the core forms an almost complete magnetic circuit, so the attractive force between the fixed core and the movable core increases, and this can be maintained with a small coil current. can. From this point of view, an AC electromagnet device as shown in FIG. 1 or 2 is known, in which a DC current obtained by rectifying an AC power supply is applied to an operating coil of an electromagnet section including an iron core and an operating coil.

In FIG. 1, the operating coil 1 is connected to the DC terminal of a full-wave rectifier 3 through a parallel circuit of a normally closed contact 6 and a resistor 2, and the AC terminal of the full-wave rectifier 3 is connected to the DC terminal of the full-wave rectifier 3 through a switch 4. and is connected to an AC power source 5. The normally closed contact 6 is a contact that is linked to the movable iron core and is switched before and after closing. In this electromagnet device, when a switch 4 is closed, a DC current rectified through a gold wave rectifier 3 flows into an operating coil 1 and attracts the movable iron and the core. When the movable core is attracted, the normally closed contact 6 opens and the resistor 2 is inserted in series with the operating coil 1.

With this configuration, direct current flows through the operating coil, so the movable core can eliminate the iron loss υ.
The laminated core is an enclosed core made of mild steel, etc., and the material cost and man-hours can be saved by eliminating the square coil. Furthermore, after the movable core is attracted, a resistor is inserted to reduce the coil current, so the copper loss of the operating coil is small and the coil itself can be made smaller. However, in this case, the copper loss of the resistor 2 is large and a resistor with a large allowable input is required. Next, in FIG. 2, a parallel circuit of a normally closed contact 6 and a non-polar capacitor 7 is connected in series to the AC terminal of the full-wave rectifier 3, and is connected to an AC power source 5 via a switch 4. capacitor 7
is short-circuited to the normally closed contact 6 before it is turned on. The operating coil 1 is directly connected to the DC terminal of the full-wave rectifier 3. In this electromagnet device, when a switch 4 is closed, a direct current rectified by a full-wave rectifier 3 flows into an operating coil 1, and a fixed iron core attracts a movable iron core. When the movable iron core is attracted, the normally closed contact 6 opens and the capacitor 7 is inserted in series with the AC terminal of the full-wave rectifier 3, thereby reducing the current flowing through the operating coil 1.

This configuration has the advantage that, like the configuration shown in FIG. 1, there is no loss due to alternating current (such as that caused by alternating current), and there is also little loss in the capacitor.

However, there are disadvantages in that the reactive power increases after turning on, and the life of the contacts is shortened because they open and close a capacitive load.

Another disadvantage is that the device becomes larger because a capacitor with a high withstand voltage, large capacity, and therefore a large external shape is attached to share the power supply voltage.

[Purpose of the invention]

It is an object of the present invention to eliminate the above-mentioned drawbacks and to provide an AC electromagnet device which has low loss, is small in size, and has high reliability.

[Key points of the invention]

In order to achieve the above-mentioned object, the present invention includes a plurality of operating coils wound around a fixed core that attracts one movable core, a diode that connects the operating coil to its DC terminal, and a diode that connects the operating coil to its DC terminal. The AC electromagnet device is equipped with a contact point that operates to change the connection of each operating coil, and the respective operating coils are connected in parallel when attracting an iron core, and are connected in series after attracting an iron core. In other words, a direct current rectified by a full-wave rectifier is passed through the operating coil that attracts the iron core to excite it, eliminating the drawbacks caused by alternating current, and the operating coil is divided into multiple parts and connected in parallel when attracting the iron core. A large current is applied to the core to ensure attraction of the core, and after the core has been drawn in, this operating coil is connected in series to maintain the attracted core with a small current, thereby saving staining force and downsizing the operating coil. The structure is designed to measure the following. Note that the contact may be a normally closed contact that works with the movable core as is common in this type of equipment, but it is also possible to use a normally closed contact that operates in response to the current flowing when the core is attracted, or a normally closed contact that operates only when the power is turned on. It is also possible to use a one-shot type normally open contact that closes and opens after the core is drawn in. If these contacts are used as non-contact switches, reliability will be further improved.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail based on the connection diagrams of each embodiment shown in FIGS. 3 to 6. In any of the embodiments, the electromagnet device includes a fixed core (not shown), a movable core attracted to the fixed core, and an operating coil 1 that is divided and wound around the same fixed core (1a, 1 in the case of divided parts).
b, Ic...), and several normally closed contacts 6 (in the case of multiple contacts, 6a,
6b...), and a full-wave rectifier 3 (in the case of multiple units, 3a,
3b...) and several diodes 7.8°9 (in case of multiple diodes, a, b, c, respectively) that determine the current direction.
) and a control circuit.

In FIG. 3, the control circuit connects in series one of the two operating coils la and lb, one operating coil 1a, a diode 7, and the other operating coil 1b, with both ends connected to a full-wave rectifier. It is connected to the DC terminal of 3. It is diode-connected to the operating coil 1a. In other words, this control circuit has two normally closed contacts 6a and 6b.
When the two operating coils], a, and lb are connected in parallel, and a diode 7 is connected between them, a single-phase AC voltage is applied to the AC terminals R and S of the full-wave rectifier 3. Then, the voltage appearing at the DC terminal of the full-wave rectifier 3 is the same as that of the series circuit of the operating coil 1a and the normally closed contact 6a.
A DC current is applied to the series circuit of the normally closed contact 6b and the operating circuit 1b, and flows separately to the respective operating coils Ia and lb. At this time, since the anode side of the diode 7 has a lower stain level than the cand side, no current flows through the diode 7.

When a direct current flows through the two operating coils la and lb, the movable core is attracted to the fixed core. Then, two normally closed contacts 6a,
6b opens and the two operating coils la.

1b are connected in series via a diode 7. Therefore, the two operating coils la and lb share the voltage of the DC terminal of the full-wave rectifier 3, and the current flowing through each operating coil la and lb becomes approximately half that when the movable iron core is attracted.

This current is sufficient to maintain the attracted iron core. At this time, if the current required for turning on is 2 people, the current required after turning on is 1/2.
Therefore, the current after turning on is reduced to approximately 1/4 of the current before turning on.

FIG. 4 shows a different embodiment of the present invention, in which the operating coils Ia, lb, Ic, ld are divided into four, cathodes 8a, 8b, 8c and diodes 9a, 9.
b and 9c are connected in parallel. This series circuit is the positive terminal of the full-wave rectifier 3 (hereinafter referred to as ■ terminal).
One end of the operating coil 1a and the normally closed contact 6b are connected to the DC terminal, and one end of the operating coil 1d on the negative electrode side (hereinafter referred to as the ○ terminal) and the normally closed contact 6a are connected. and a normally closed contact 6a.

Diodes 7a to 7c are inserted so that when 6b is opened, operating coils 1a to 1d are connected in series.

The normally closed contact 6a is connected between the ○ terminal side of the operating coil 1a and the ○ terminal of the full-wave rectifier 3, and the normally closed contact 6b is connected between the ■ terminal side of the operating coil 1d and the ■ terminal of the full-wave rectifier 3. connected between. In this embodiment two normally closed contacts 6
When 'a, 6b are closed, the following (a) (b) (
c) The four main circuits shown in (d) are formed.

(a)...■Terminal - Coil la mA6a-e terminal (c)...■Terminal - Contact 6b - Diode 3c, 8b
- Coil 1b - Diode 9a - Contact 6a - () Terminal (c)...■Terminal - Contact 6b - Diode 8c - Coil IC - Diode 9a.

9b - Contact 6a - 0 terminal (d)... ■ Terminal - Contact 6b - Coil 1d - θ terminal When the normally closed contacts 6a and 6b are closed in this way, one operating coil is always inserted in each circuit. ing. Therefore, when a single-phase AC voltage is applied to the AC terminals R and S of the full-wave rectifier 3, the voltages appearing at the DC terminals of the full-wave rectifier 3 are (a), (b), (c), and (d). ) is applied to each of the four circuits of each operating coil la.

Direct current flows through lb, lc, and ld. At this time, some operating coils lb and lc are connected to other operating coils Ia.
.

Although current flows through many diodes in 1d,
The forward resistance of this diode is the operating coil la.

Since the resistances of lb, lc, and ld are very small compared to the resistances of lb, lc, and ld, the currents of each operating coil la, lb, lc, and ld are approximately equal. This current causes the movable core to be attracted to the fixed core. Normally closed contacts 6a and '6b linked to the movable iron core are opened when the movable iron core is attracted or just before it is attracted, and this circuit is formed as follows: ■Terminal - Coil 1a - Diode 7a' - Coil 1
b-Diode 7b-Coil IC-Diode 7cm coil 1d-Theta terminal are connected one after another to form one series circuit. Therefore, each operating coil la, lb, l
Since c and Id mutually share the voltage at the DC terminals of the full-wave rectifier 3, the current flowing through each operating coil is reduced to approximately 1/4 of that when the movable iron core is attracted.

This current is sufficient to maintain the attracted core. At this time, assuming that the current required for turning on is 4A, the current borne by the full-wave rectifier after turning on is approximately L/16 of the current before turning on.

In the circuit shown in FIG. 4, the operating coil can be divided into two or more arbitrary numbers, and the current changes according to the number of divisions.

FIG. 5 shows a different embodiment of the present invention, in which two diodes 7a are connected between the operating coils la and Ib0, which are divided into two.
, 7b in series circuit and other two diodes 8a, 8
A series circuit of operating coils la and lb is formed by inserting a circuit connected in parallel with the series circuit of b, and both ends of this series circuit are connected to diodes 3a and 3b.

DC terminal of the full wave rectifier formed by 3c and 3d■e
A normally closed contact 6 is connected between the connection point of the diodes 7a and 7b and one AC terminal R, and between the connection point of the diodes 8a and 8b and the other AC terminal S.
a and 6b are connected.

Further, FIG. 6 shows a different embodiment of the present invention, in which two divided operating coils la and lb are connected in series via two series-connected diodes 8a and 8b, and both ends of this series circuit are connected in series. is diode 3a.

The diode 8a is connected to the DC terminal ■○ of the full-wave rectifier formed by 3b, 3c, and 3d, and the operating coil 1a on the anode side of sb is connected to the ■terminal, and the operating coil 1b on the cathode side is connected to ○.
A diode 7a is connected with its cathode on the AC terminal R side between the operation coil 1a and one AC terminal, for example, the R terminal, of a full-wave rectifier device consisting of the operation coil 1a and the diode 8a, and the operation coil 1b and A diode 7b is connected between the connection point with the diode 8b and the same AC terminal R of the full-wave rectifier, with its anode facing the AC terminal R side. Also, two diodes 8a connected in series,
A normally closed contact 6 is connected between the connection point of 8b and the other AC terminal S.
a is connected. In other words, in the circuit shown in FIG. 5 and the circuit shown in FIG. 6, when the normally closed contacts 6b and 6b (excluding 6b in FIG. 6) are closed, the four diodes 3a

The operating coil 1a is connected to the DC terminal of the full-wave rectifier 3 formed by the diodes 3b, 7a, and 8a, and the full-wave rectifier 3b is formed by the other four diodes 7b, 8b, 3%, and 3d. The operating coil 1b is connected to the DC terminal of the controller.

are connected to common R and S terminals, respectively.

In both the circuits shown in FIGS. 5 and 6, when a single-phase AC voltage is applied to the R and S terminals, each full-wave rectifier 3
8.3! Depending on the voltage appearing at the DC terminal of I, a DC current flows independently through each of the operating coils la and lb.

Then, the movable core is attracted to the fixed core, and at this time, the normally closed contacts 5a and 6b (excluding 6b in the case of FIG. 6) which are interlocked with the movable core are opened. This makes the circuit diode 3
A, 3b, 3c, and 3d have two divided operation coils la and lb connected to the DC terminals of the full-wave rectifier including diodes 7a, 7b, and 8a.

8b (excluding 8a and 8b in FIG. 6), forming a series circuit. Therefore, the two operating coils la
, lb share the DC voltage rectified by the full-wave rectifier, so the current flowing through each of the operating coils la and 1biC is reduced to approximately half that when the movable iron core is attracted. This current is sufficient to maintain the attracted movable core. Moreover, the current borne by the full-wave rectifier is approximately 1/4 of the current when attracting the iron core.

In the above embodiment, the contact that connects the plurality of divided operation coils from parallel to series is a normally closed contact that works with a movable contact. It may be a closed contact, or it may be a one-shot normally open contact with a timer that operates instantly when the power is turned on and closes only when the core is attracted. Furthermore, if these contacts are each non-contact switches that operate as described above, reliability will be improved. However, when using such a non-contact switch, the switching element can be a transistor because the circuits shown in Figures 3 and 4 switch on and off DC current, but the circuits shown in Figures 5 and 6 switch on and off AC current. [Effects of the Invention] As described above, in the AC electromagnet device according to the present invention, the electromagnet section is operated by passing a DC current rectified by a full-wave rectifier to the operating coil, and is small and consumes little power. At the same time, the operation coil is divided into multiple pieces, and when the core is attracted, these multiple operation coils are connected in parallel to flow a suction current to the core, and after the core is attracted, they are connected in series to maintain the attracted core. Since the current is low, power consumption is low, and the operation coil and full-wave rectifier can be made compact for short-time ratings, and the overall size can be made small because no large parts are attached. Can be done. Note that the reliability can be further improved by using non-contact elements as the contacts.

[Brief explanation of the drawing]

1 and 2 are wiring diagrams showing the main wall portions of a conventional AC electromagnet device, respectively, and FIGS. 3 to 6 are wiring diagrams showing main parts of different embodiments of the AC electromagnet device according to the present invention. be. 9b, 9c...diodes. ya ((2) 1″￥′Z(2)

Claims (1)

[Scope of Claims] 1) An operating coil wound around a fixed core that attracts one movable core and divided into a plurality of parts, a full-wave rectifier to which this operating coil is connected to its DC terminal, and each of the above-mentioned A diode connected to the operating coils determines the current direction of these operating coils, and a contact that is normally closed and operates to switch when the movable core is attracted, and each of the operating coils has a contact point. An AC electromagnet device characterized by having a control circuit that is connected in parallel when the contact is closed and connected in series when the contact is opened. 2. The AC electromagnet device according to claim 1, wherein the contact is a normally closed contact of a time-limited operation type that is operated by a current flowing when the iron core is attracted. 3) The AC electromagnet device according to claim 1, wherein the contact is a normally open contact that closes when the power is turned on and opens after the core is attracted. 4. An AC electromagnet device according to any one of claims 1 to 3, wherein the contact is a non-contact switch.