JPS6188419A - Excitation circuit for electromagnet - 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 [Field of Application of the Invention] The present invention relates to an excitation circuit for an electromagnet, and particularly to a circuit suitable for downsizing an excitation circuit for a DC electromagnet.

[Background of the invention]

This type of excitation circuit is used in electromagnetic switches, electromagnetic relays, etc., and requires a large excitation current when transitioning from the break state to the make state. It is configured to save power so that only a small amount of excitation current is required to maintain the current.

FIG. 1 shows such a conventional excitation circuit. 1st
The figure is from Utility Model Application Publication No. 58-198442. In the figure, 1 is a control circuit, S is a power switch, and S is a relay contact. When the power switch S1 is off,
A diode D is connected to the base of the transistor Q, and a resistor R is connected to the base of the transistor Q.
4, a base current flows, which turns on the transistor Q. When transistor Q is turned on, transistor Q is also turned on. Therefore, it can be considered that both ends of the resistor R are short-circuited by the transistor Q+ and that the resistor R8 is not connected. In this state, when power switch S1 is turned on, power supply E1 switch S8, resistor R7, transistor 01% excitation coil C
A current flows to C, and the excitation coil CC closes the relay contact S2. By closing the contact S, the contact S1
, a current flows into the capacitor C via the resistor R8. Resistor R8 and capacitor C constitute an integrating circuit, and the potential at point P rises with a fixed time constant (delay time).

During this rising process, when point P reaches a potential that turns diode D from an on state to an off state, at that point, diode D turns off, and subsequently transistor Q1,
Transistor Q1 is also turned off. As a result, the resistor R1 is no longer short-circuited at both ends, but is inserted in series in the current supply circuit to the relief coil CC. As a result, the current flows by the amount of resistance R1, and the excitation coil CC has resistance R.
The current is smaller than the current at the time of short circuit in No. 1.

From the above, we understand the following. First, when the power is turned on, a current caused only by the resistor R2 flows through the excitation coil CC. This current is a large current required to turn on contact S.

Second, when the -phase power supply is turned on and after the delay time vertical vortex of the integrating circuit, the excitation coil CC has resistors R, ,R,
An electric current θ ( θ ) flows based on the added resistance.

This II flow can be reduced compared to the sub-flow at the time of startup. After the contact S is turned on, the contact S is turned on with a small current compared to the flow at startup.
It is possible to keep the switch on. Similarly, L is a load connected in series to the contact S2. 1
a to 1d are connection lines.

In another conventional example shown in FIG. 2, when the power switch Sl is turned on when the transistor Q1 is in the on state, the power source E
1 switch SL, excitation coil CC,) synister Q, turns on contact S2, but after turning on contact S, transistor Q1 turns off, causing transistor C) +, FJAH coil CC. By de-energizing the surrounding circuit, the holding coil HC is able to maintain the on state of the contact S.

By the way, in the first conventional example shown above, if the control circuit 1 is a black box having four terminals T1 to T4, at least four wires are required to connect the control circuit 1 to the device. That is, the wiring 1a connects one of the electromagnetic switches S, the diode D, and the resistor R3 via the terminal T4, the wiring 1b connects the collector of the resistor R4, the transistor Q, and the ground side via the terminal T, and the terminal T. ,
A wiring IC is required to connect one side of the switch S to the resistor R1 and the emitter of the transistor Q1 through the terminal T1, and a wiring 1d to connect the collector of the transistor Q1 to the resistor R8 and the excitation coil CC through the terminal T1. Become. Therefore, not only is wiring time-consuming, but also a large amount of space is required to route the wiring.

Furthermore, in the second conventional example shown above, the control circuit 11 becomes a black box having three terminals T1 to T.
Switch Sl is connected via three wires a, llb, and llc.
, the ground side, and the excitation coil CC. Contact S2
When turned on, the excitation coil CC of the control circuit 11 becomes de-energized, and the off state of the contact S is maintained only by the holding coil HC. Therefore, when used continuously, the holding coil H
C has considerable heat, and therefore it is difficult to suppress the temperature rise.

Furthermore, in both of the two conventional examples, it is necessary to connect both the input and output ends of the fljt m coil, so in order to shorten the length of the connection wire and prevent an increase in the routing space, it is necessary to connect the fljt m coil near the excitation coil CC. Moreover, since the control circuit 1 has a large number of component parts, it is difficult to make it compact.

[Object of the Invention] In consideration of the above-mentioned circumstances, the present invention can be arranged easily, can be made compact, and can suppress the increase in hemostasis of the excitation coil when used continuously. It is intended to provide the excitation cycle of the electromagnet.

[Summary of the invention]

In order to achieve the above object, the present invention provides a power switch connected to the source switch, an excitation coil connected in series to the source switch and capable of opening and closing the electromagnetic switch, and a power switch connected to the excitation coil. Remove the control (e) circuit connected in series,
The control circuit is connected to the excitation coil and the surface die 1j,
The present invention also includes a suppressing means for controlling the current, and a current limiting stage connected in parallel to the side end of the suppressing means.

At the same time as the above-mentioned flow section, a transistor whose emitter and collector were connected to the side of the inhibiting means was connected to the base of the transistor in an open circuit. 74 resistance,
It may be composed of a capacitor and K connected between the adjustment resistor and the collector of the transistor.

[Nine examples of inventions]

Hereinafter, the present invention will be explained in detail with reference to Sections 3 to 8. Figure 6 shows the first excitation circuit of the electromagnet according to the present invention.
A real example is shown.

In FIG. 3, a power switch S1 is connected to the DC power source E in both directions, and an exciting coil CC is connected in series to the switch S1. The excitation coil CC opens and closes the contact S2 of the electromagnetic device. Excitation coil CCK
A diode D for absorbing back electromotive force is connected in parallel with .

Further, a control circuit 21 is connected in series to the excitation coil CC. The control circuit 21 includes a suppressing resistor R1 which is connected in series with the excitation coil CC and is a suppressing means for controlling the excitation current, and an emitter and a collector are connected in parallel to the suppressing resistor R5, respectively tL.

and a PNP transistor Q that shorts the suppression resistor R1.
, an adjusting resistor R2 connected in series to the base of the PNP transistor Q1 and limiting the current, and a PNP transistor Ql connected between the adjusting resistor R2 and the collector of the PNP transistor Q1. A diode D is connected between the emitters of the capacitor C and the PNP transistor Q, and accelerates the discharge of the capacitor C when the power switch S is turned off.

It is composed of. Note that 2a and 2b indicate terminals for the exciting coil CC.

In this excitation circuit 21, when the switch SI is closed, the excitation coil CC1, the emitter of the transistor Q, and the adjustment resistor R
When a pace current flows through the 2s capacitor C, the transistor Q momentarily turns on (on state).At that time, the excitation current flows through the excitation coil CC.

Flows through the emitter and collector of transistor Q, IJj
Contact Stk is turned on by the action of bi coil CC.

Also, when the transistor Q is on, there is a slight deviation between the base and the emitter, so that a current flows between the adjustment resistor R1 and the capacitor C, and the base gtffl charges the capacitor C. When the potential difference between the base and emitter disappears, the transistor Q is turned off.

After turning off the transistor Q, the exciting current or the magnetic sensing coil CC,
By increasing the resistance υJ resistance R, f(,), it is reduced to the magnitude necessary to keep the contact S2 in the on state, and its state T! is maintained at 1, which turns off the switch S1. Therefore, the contact When S2 is in the ON state, the power consumption of 1 Lt can be reduced compared to when it is ON.

By connecting the ibl, l enveloping path 21 and the magnetic coil CC in series in this way, it is possible to eliminate the need for two wires to connect the iij control circuit 21 to other components.

That is, the wiring 21 connecting the excitation coil CC via the terminal T1
There are two wires: e and a wire 21b connecting the capacitor C and the ground wire via the terminal T. Therefore, compared to the conventional example shown in FIG. 1, it is possible to reduce the number of wiring lines and also to reduce the estimated routing space. Moreover, the control circuit 21 includes a suppression resistor R8,
Since it is composed of five parts: transistor Q1, resistor R6, capacitor C1, and diode D1, the number of parts can be reduced compared to the conventional examples shown in Figs. 1 and 2, and it can be made more compact. can.

Next, examples in which the present invention is incorporated into various devices will be described in detail.

144 and 5 show the case where the present invention is applied to an output relay of an overcurrent protection relay. That is, in this case, as shown in FIG. 5, a large number of output contact terminals 3a are provided on the printed circuit board 3, each connected to each other by a printed conductor.
and an external connection terminal 3b are arranged, and a terminal 2 of an excitation coil CC for the output relay is arranged near the terminal group.
Suppose that a and 2b are arranged, and there is an empty space 4 at a position 5' apart from them, as shown by two points 1Jf4&I.

Therefore, if the control circuit 21 is placed in the empty space 4 and a printed mat is inserted between the 1tilH# circuit 1 and the terminal 2a12b, the gap between the terminals 2a, 2b and the empty space 4 is Since the flint rings of Toki are not in "cD", there is a possibility that it will be difficult in terms of space.

However, in an unproductive example, the control (g) circuit 1 is connected in series with the excitation coil CCK, so the connecting conductor between both sides can be completed with one conductor 21e, and therefore, the printed It is unavoidable to enlarge the board 3 or make it three-layered, and it is also possible that the connecting conductor between the two sides is connected to another printed body and the line between the two sections. I'm going to say it.

FIG. 6 shows a case in which the magnetic contactor according to the present invention is in full use. In this case, the control L is placed in the space between one coil terminal 2b of the excitation coil CC and the mounting board surface. In addition to arranging the 2+ path 1, the control circuit 1 and the coil terminal 2b are connected, and the length of the connecting wire can be minimized, and the space can be used effectively when installing the control circuit 1. I can do it.

FIG. 7 shows a second embodiment of the excitation circuit according to the invention. In this embodiment, the support circuit 31 is a suppression resistor R
A holding coil HC is used in place of No. 3, and the holding coil H
C controls the excitation flow.

In addition, when the contact S is turned on by closing the switch S1, the current flows through the exciting coil C.
Since it flows through the series circuit of both C and holding coil HC,
When used continuously, it is possible to reduce the margin for the temperature rise of the coil, and the temperature rise can be suppressed to that extent. Moreover, since the holding coil HC and the excitation coil CC are generally formed in the same bobbin, the control circuit 31 can be installed on one side of the excitation coil CC, as shown in FIG. 1, the control circuit 31 can be integrated with the excitation coil CC, and the control circuit 3
1 through terminals T and %T, respectively? f1431
Since it can be connected to the excitation coil and earth IIF:+ at a% 31b, space can be saved. Further, in the above embodiments, the transistor is not limited to the PNP type, but may be an NPN type depending on the polarity of the circuit. Furthermore, the control circuit 21 and the control circuit 31 except for the holding coil HC may be formed into thick film ICs.

〔Effect of the invention〕

As described above, according to the present invention, the control circuit is connected in series with the excitation coil, which makes it possible to reduce the number of wires and simplify the routing, as well as reduce the number and strength of component parts. Therefore, it has the advantage that it can be easily wired and can be made compact.

[Brief explanation of the drawing]

1; R1 is a circuit diagram showing a conventional excitation circuit, and FIG. 2 is a circuit diagram showing another conventional excitation circuit. FIG. 3 is a circuit diagram showing a first embodiment of an excitation circuit for an electromagnet according to the present invention;
@ Figure 4 is a perspective view of the excitation circuit attached to the overcurrent protection relay, Figure 5 is an explanatory plan view showing the printed circuit board of the overcurrent protection relay, and Figure 6 is a perspective view of the excitation circuit attached to the electromagnetic contactor. , FIG. 7 is a circuit diagram showing a second embodiment of the excitation circuit for an electromagnet according to the present invention, and FIG. 8 is an explanatory plan view in which the control circuit of FIG. 7 is assembled to an excitation coil. E...Power supply, S...Power switch, S...?
1f, transfer point 1CC... excitation coil, 21181...
- Control circuit, R,, HC... Suppression means, R3... Resistor s Ql... Transistor, C... Capacitor. No. 17/, -L $ 2 (2) No. 3 Figure 1b Katana $ 7 ri No. 4 Kuchi Da Kudo-1 No. B Kuchi

Claims (1)

[Claims] 1. A power switch connected to a power source, an excitation coil connected in series to the power switch and capable of opening and closing an electromagnetic contact, and a control circuit connected in series to the excitation coil. An electromagnet, characterized in that the control circuit comprises a suppressing means connected in series with the excitation coil and controlling the current, and a current controlling means connected in parallel to both ends of the suppressing means. Excitation circuit. 2. The current control means includes a transistor having an emitter and a collector connected to both ends of the suppressing means, a resistor connected in series to the base of the transistor, and a transistor connected between the resistor and the collector of the transistor. An excitation circuit for an electromagnet according to claim 1, characterized in that the excitation circuit is constituted by a capacitor having a capacitor.