JPS60230331A - Ac load reed relay - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (8) Technical Field of the Invention The present invention relates to a reed relay, and more particularly to a reed relay for a large current load on an AC power supply.

(bl Technology background) Reed relays, which are made by winding a coil around the outer periphery of a reed switch, have a sealed structure, so they are not affected by dust, moisture, harmful gases, etc., and their operation and recovery times are shorter than electromagnetic relays. Because it is small, chatter time is short, and IC drive is easy, it is widely used to fill the gap between semiconductor switching elements and electromagnetic relays.However, for AC power loads, for example, even with a load of 8C 100V, the peak value is 140
Even if there is no abnormality in the open state, sustained discharge may be induced during bounce due to operation or due to the reduced contact voltage when opened, resulting in electrical disconnection failure. Furthermore, if the switching current of the contact is large, a chattering phenomenon of the contact called electromagnetic bounce (EMB) occurs when the contact is opened, and the contact is destroyed by the discharge at that time, making it easy to cause a failure in opening. Therefore, it is necessary to incorporate new mechanisms into the configuration of reed relays used for high-voltage, large-current AC power loads, such as opening and closing contacts near the AC load to zero.

(C) Prior Art and Problems Figure 1 shows the configuration of a conventional reed relay, in which a drive coil 2 is wound around the outer circumference of a reed switch 1, and the reed switch 1 is connected to an AC power source 4 via a load 3. It is connected to the. On the other hand, the drive coil 2 is connected to a control circuit consisting of a drive power source 5 and a switch. In FIG. 1, when the switch 6 is closed, current flows through the drive coil 2, the contacts of the reed switch 1 are closed, and the load 3 is energized. Next, when the switch 6 is opened, the current flowing through the drive coil 2 is cut off, and the contacts of the reed switch 1 are opened, and the current flowing through the load 3 is cut off. However, since there is no relationship between the opening/closing timing of the contacts of the reed switch 1 and the load current, there is a possibility that the contacts are opened/closed when the load current is at its peak. Therefore, if such a reed relay is used for a high-voltage, large-current AC power load, the contacts will be destroyed in a very short period of time due to the above-mentioned reasons.

(dl Purpose of the Invention The purpose of the present invention is to provide a reed relay that has a synchronization function (zero cross function) that opens and closes the contacts near the AC load becoming zero, and can be used for high voltage and large current AC power loads. It's about doing.

(e) Structure and purpose of the invention is to wind around the outer periphery of a reed switch, in addition to a drive coil, an off-trigger coil and an on-trigger coil having magnetic fields in opposite directions, the drive coil being connected to a control circuit, and the off-trigger coil being connected to a control circuit. This is achieved by connecting the reed switch and the load circuit via the diode, and connecting the on-trigger coil to the load circuit via the diode. That is, the present invention adds an off-trigger coil and a 1-trigger coil that generate magnetic fields in opposite directions, which are connected to a load circuit via a diode, to a reed relay, thereby allowing current to flow through a drive coil connected to a control circuit. Even if the current flowing through the drive coil is cut off, the reed switch contacts will not open until the AC load is around zero. , a zero-cross function is provided to the reed relay.

(f) Embodiments of the Invention The present invention will be described in detail below with reference to the accompanying drawings, in which the same objects are represented by the same reference numerals throughout all seven drawings.

FIG. 2 is a configuration diagram showing an embodiment of the reed relay according to the present invention, and FIG. 3 is an external view.

In Figures 2 and 3, lead terminals 7A, 7B, 8
A, 8B, 9A, and 9B bobbin 10 is wound with an off-trigger coil o, a bud trigger coil 12, and a drive coil 2 from the inside, and each coil has a lead terminal 7A, 7B, 8A, 8B, 9A, 9
Connected to B. The reed switch l is fitted into a hole 13 in the center of the bobbin 10, and its lead wire 14
are lead terminals 7A, 7B, 8A, 8B, 9A,
It is soldered to the printed circuit board 15 together with 9B.

The off-trigger coil 11 and the drive coil 2 are configured to generate magnetic fields in the same direction, and the on-trigger coil 12 is configured to generate magnetic fields in the opposite direction. The drive coil 2 is connected to the drive terminal 16
A and 16B, and a diode 17 is connected between the drive terminals 16A and 16B in preparation for a transient current generated when the drive coil 2 is energized. In addition, a diode 18 with a bridge configuration is mounted on the printed circuit board 15, and the off-trigger coil 11 is connected to the reed switch 1 and the on-trigger coil 1.
2 is connected to two poles of a diode 18 via a resistor 19, and the other two poles of the diode 18 are connected to load terminals 20A and 20B.

The resistor 19 is used to adjust the magnetic field generated by the on-trigger coil 12 and to prevent the load 3 from operating due to the current flowing through the on-trigger coil 12, and has a resistance value sufficiently larger than that of the load 3. Note that all of these wirings are performed via wiring patterns formed on the printed circuit board 15, and the outside of the reed relay is covered with a cover 21 and a bottom plate 22. A drive power source 5 is connected to the drive terminals 16A and 16B via a switch, and an AC power source 4 is connected to the load terminals 2OA and 20B via a load 3.

Next, the operating principle of the reed relay according to the present invention will be explained. In Figures 2 and 3, the number of turns of the off-trigger coil 11 is Na, the current is Ea, and the resulting magnetic field is Ha.
, the number of turns of the on-trigger coil 12 is Nb, the current is ib,
The resulting magnetic field is nb, the number of turns of the drive coil 2 is Nc, the current is Ic, the resulting magnetic field is Hc, the reed piece energizing current is ■, its maximum value is Io, and the resulting demagnetizing field at the overlapped portion of the reed piece is Hd. Then Ha = Na bow a = (
Ha) o l cos ωt l ((Ha) o is the maximum value of Ha] Hb = Nb - Ib - () Ib) ol cos ωt l [
()Ib)o is the maximum value of Hb] Hc=Nc·Ic)1d--51=-51o1cos ωtl. Therefore, the composite magnetic field H+ when the three-layer coil is energized and the reed switch contacts are closed is expressed by the following equation.

Hr =)Ia+Hb+Hc+Hd =Na ・fa=Nb ・Ib+Nc -Ic-5I0
1CO8ωt1 Also, when the current flowing through the drive coil 2 is cut off but the reed switch contact is closed, the composite magnetic field H2 is expressed by the following equation.

H2=Na・Ia−Nbib−51o 1 cos ωt
l= (Na-5)Io l cos ωt l −
Nb ・Ib [The reed switch and off-trigger coil are connected in series, Ia = Io l cos ωt
l] On the other hand, when no current flows through the drive coil 2 and the reed switch contact is open, the composite magnetic field H3 is expressed by the following equation.

H3=Hb=-Nb·Ib Furthermore, the composite magnetic field H4 when current is flowing through the drive coil 2 but the reed switch contact is open is expressed by the following equation.

H4 = Hb + Hc = -Nb -1b + Nc ・Ic Here, in order for the contact current to cross zero when the reed switch contacts open and close, the reed switch's touching value is pi,
If the open value is Do, then H2-(Na-5)Io l c
os ωt 1-Nb-1b= (Na-5)Io-N
b-1b>DOHa −−Nb −Ib+Nc −1c
<Nc/Ic to impress the PI or reed switch>
The conditions for being a PI must be met.

- In the reed relay according to the present invention configured to satisfy the above conditions, the magnetic field generated by each coil and the demagnetizing field due to the current flowing through the reed piece are shown in FIG. Fig. 4 (al is the magnetic field caused by the drive coil 2, Fig. 4 (bl is the magnetic field caused by the off-trigger coil 11, Fig. 4 (C) is the magnetic field caused by the on-trigger coil 12, Fig. 4 fdl is the reduction caused by the current flowing through the lead piece. The magnetic field, Fig. 4 fe) is the composite magnetic field,
FIG. 4 (fl is the load current.

Figure 4 (al) When the current flowing through the drive coil 2 is cut off at point A, in the case of a conventional reed relay, the contacts of the reed switch open at point A°, which is delayed by the recovery time, that is, near the maximum value of the load current. However, in the case of the reed relay according to the present invention, the current flowing through the drive coil 2 is A
Even if the contact breaks at point A'', the contact will not open even at point A'' because the magnetic field from the off-trigger coil 11, the magnetic field from the on-trigger coil 12, and the demagnetizing field from the reed piece current are acting. It is only opened at the point where the composite magnetic field value reaches the open value of the reed switch, that is, near the load current is zero.On the other hand, when current is passed through the drive coil 2 at point B, if it is a conventional reed relay, the operating time is The contacts of the reed switch will close at point B, which is delayed by a certain amount of time, that is, near the maximum value of the load current.However, with the present invention, even if current is applied to the drive coil 2 at point B, the reed switch will not turn on. Since the magnetic field by the trigger coil 12 is acting, the contact will not be closed even at point B''. The device is closed only at the point where the composite magnetic field of the magnetic field generated by the drive coil 2 and the magnetic field generated by the on-trigger coil 12 reaches an impressive value, that is, when the load current is near zero. When the reed switch contacts are open, only a small amount of alternating current flows to the load 3 through the on-trigger coil 12 and the resistor 19, but when the reed switch contacts are open, the reed switch and off-trigger coil 1
1, and a large amount of alternating current flows through the load 3.

FIG. 5 is a configuration diagram showing another embodiment of the reed relay according to the present invention. In the figure, two-layer off-trigger coils 11A and IIB, two-layer on-trigger coils 12A and 12B, and a drive coil 2 are wound around the outer circumference of a reed switch 1, and off-trigger coils IIA and I
The IB and drive coil 2 are configured to generate magnetic fields in the same direction, and the on-trigger coils 12A and 12B are configured to generate magnetic fields in opposite directions. Drive coil 2 connects drive terminals 16A and 1
6B, and a diode 17 is connected between the drive terminals 16A and 16B in preparation for a transient current generated when the drive coil 2 is energized. One end of the off-trigger coil IIA is connected to the load terminal 2OA via the diode 18A, and the other end is connected to the load terminal 2OA via the reed switch 1.
- One end of the off-trigger coil IIB is connected to the load terminal 20A via the diode 18B, and the other end is connected to the load terminal 20B via the reed switch 1, and one end of the on-trigger coil 12A is connected to the load terminal 20B via the diode 18A. The other end of the on-trigger coil 12B is connected to the load terminal 20A via a resistor 19, and the other end of the on-trigger coil 12B is connected to the load terminal 20A via a diode 18B. . The resistor 19 is used to adjust the magnetic field generated by the on-trigger coils 12A and 12B and to prevent the load 3 from operating due to the current flowing through the on-trigger coils 12A and 12B, and has a sufficiently large resistance value compared to the load 3. .

The magnetic fields generated by each coil are shown in FIG.

Fig. 6(a) shows the magnetic field caused by the drive coil 2, Fig. 6(b)
is the magnetic field due to off-trigger coil IIA (shown as a solid line)
and the magnetic field due to off-trigger coil IIB (indicated by a broken line), FIG. The demagnetizing field due to the applied current, FIG. 6(11) shows the composite magnetic field, and FIG. 6(f) shows the load current.

Fig. 6 (al) Even if the current flowing through the drive coil 2 is cut off at point A, the off-trigger coil IIA or II
Magnetic field due to B, on trigger coil 12A or 12B
Since the magnetic field is acting, the contact will not open even at point A'. Then, at the point where the combined magnetic field value reaches the open value of the reed switch, that is, when the load current is near zero, it is closed and opened. On the other hand, even if current is applied to the drive coil 2 at point B, the contact will not be closed even at point B because the magnetic field from the on-trigger coil 12A or 12B is acting. And the magnetic field by the drive coil 2 and the on-trigger coil 12A or 12B
It is only closed at the point where the composite magnetic field of the magnetic fields reaches an impressive value, that is, near the point where the load current is near zero.

FIG. 7 is a configuration diagram showing still another embodiment of the reed relay according to the present invention. In both the embodiments shown in FIGS. 2 and 5, even if the reed switch notch is open, leakage current flows through the on-trigger coil and the resistor. This embodiment uses a reed switch 1 in a reed relay shown in FIG.
A reed switch 1, which has a lower emotional value than the reed switch 1, is installed in parallel with the reed switch 1, and the reed switch 1 is connected in series with the on-trigger coil 2 and the resistor 19. The same effect can be obtained if the relay is provided with a reed switch 1''.) By providing the reed switch 1'' in this way, even if the current flowing through the drive coil 2 is cut off, the reed switch 1 closes and turns off. While current is flowing through the trigger coil 11, the reed switch 1° is also closed, and is opened when the magnetic field by the off-trigger coil 11 reaches the open value of the reed switch 1′.Reed switch l and reed switch 1′ Since the opening of the reed switch 1'' is performed almost simultaneously, the effect shown in FIG. 4, for example, remains unchanged, and subsequent leakage current can be cut off by the reed switch 1''. -When a current is passed through the drive coil 2, only the magnetic field produced by the drive coil 2 acts, so
First, the reed switch 1'' is closed, a current flows through the on-trigger coil 12 and the resistor 19, and the magnetic field from the on-trigger coil 12 acts on the reed switch 1, producing the effect shown in FIG. 4, for example.

The above-mentioned embodiments are all related to reed relays for AC loads, but if the drive coil is removed from this embodiment and the configuration is changed to drive a reed switch with a permanent magnet, it can be used, for example, as a float sensor or a proximity sensor. As,
Furthermore, if the configuration is changed to combine a permanent magnet and a temperature-sensitive magnetic material to drive a reed switch, it can be used, for example, as a thermal relay to control a high-voltage, large-current AC load.

Effects of the Invention As described above, the present invention has a synchronization function (zero cross function) that opens and closes the contacts near the AC load becoming zero, and is suitable for use in high voltage and large current AC power loads. We can provide reed relays that can be used.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the configuration of a conventional reed relay, Fig. 2 is a configuration diagram showing an embodiment of the reed relay according to the present invention, Fig. 3 is an external view, and Fig. 4 is for explaining the principle of operation. Figure 4 (al is the magnetic field caused by the drive coil 2, Figure 4 fbl
is the magnetic field caused by the off-trigger coil 11, Fig. 4 FC) is the magnetic field caused by the on-trigger coil 12, Fig. 4 Fdl is the demagnetizing field due to the lead current, Fig. 4 (el is the composite magnetic field, and Fig. 4 ffl is the load current). , FIG. 5 is a block diagram showing another embodiment of the reed relay according to the present invention, FIG. 6 is a diagram for explaining the principle of operation, and FIG. 6(a) shows the magnetic field due to the drive coil 2. (b) is the magnetic field caused by off-trigger coils IIA and IIB, FIG. 6 fe) is the magnetic field caused by on-trigger coils 12A and 12B, FIG.
FIG. 6 if) is a load current, and FIG. 7 is a configuration diagram showing still another embodiment of the reed relay according to the present invention. In the figure, 1 and 1' are reed switches, 2 is a drive coil, 3 is a load, 4 is an AC power supply, 5 is a drive power supply, 6 is a switch, 7 sides 7B, 8A, 8B, 9A, 9B are lead terminals, 10 is a bobbin, 11, IIA and IIB are off-trigger coils, 12.12A and 12B are on-trigger coils, 13 is a hole in the center of the bobbin, 14 is a reed switch lead wire, 15 is a printed circuit board, 16A and 16B are drive terminals, 17.18.18A and 18B are diodes, 19 is a resistor, 20A and 20B are load terminals, 21 is a cover, and 22 is a bottom plate.

Claims (1)

[Claims] 1) In addition to the drive coil, an off-trigger coil and an on-trigger coil that generate magnetic fields in opposite directions are wound around the outer circumference of the reed switch, the drive coil being connected to a control circuit, and the off-trigger coil being connected to a control circuit. A reed relay for an AC load, characterized in that the reed switch is connected to a load circuit via a diode, and the on-trigger coil is connected to the load circuit via the diode. 2. In the AC load reed relay according to claim 1, in addition to the drive coil, an off-trigger coil and an on-trigger coil having magnetic fields in opposite directions are wound around the outer periphery of the two reed switches, and the drive A reed relay for an AC load, characterized in that the coil is connected to a control circuit, an off-trigger coil and an on-trigger coil are connected in series with separate reed switches, and the coil is connected to a load circuit via the diode.