JP4494622B2 - Electromagnetic relay coil drive circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a voltage driving circuit of a coil of an electromagnetic relay (hereinafter referred to as a relay) composed of a contact and an electromagnetic coil, and relates to a power consumption of the relay coil and a temperature rise suppressing method.
[0002]
[Prior art]
The specifications of the relay are determined mainly by the rated voltage, current, and number of poles at which the contact can be opened and closed, and the rating of the electromagnetic coil that generates the contact opening / closing driving force necessary to achieve the specification is determined. The rating of the electromagnetic coil is specified by the relay manufacturer as the rated voltage of the coil.
[0003]
Such relays are used a lot for ON / OFF control of electric circuits as built-in devices. However, in recent years, the size of devices has been reduced, and the arrangement density of relays and other electronic components has increased in the devices. , The temperature rise of relays and other electronic components in equipment is a problem. In other words, the upper limit of the usable temperature is set for relays and other electronic parts, but when the density of parts increases, the temperature of each part increases due to heat generation due to power consumption in the equipment compared to the case where the density is low. As a result, it becomes necessary to use expensive parts with high upper temperature limits.
[0004]
Most of the power consumption of the relay is generated by the electromagnetic coil described above, and the influence of heat generation of the electromagnetic coil is large among the factors of the temperature rise of the relay. The effect on temperature is particularly noticeable when many relays are used in the equipment.
[0005]
[Problems to be solved by the invention]
In view of the above problems, the present invention suppresses the power consumption of the electromagnetic coil without affecting the energization of the relay contacts and the switching performance when two electromagnetic relays are simultaneously turned on and off. The object is to suppress the temperature rise in the equipment using a relay.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention utilizes the fact that there is a difference between the first energy required for attracting the electromagnetic coil of the relay and the second energy for maintaining the state after the attracting, In this catalog, it relates to the characteristics of relay coil operating voltage and return voltage. That is, in a general relay, when a voltage higher than a certain value is applied to the coil, the relay operates, and the voltage is called an operating voltage. When the coil voltage of the relay once operated is reduced to a certain value or less, it returns to the state before the relay is operated, and this voltage is called a return voltage. Generally, the operating voltage is about 80% or less of the rated voltage, and the return voltage is 10 to 30% or more of the rated voltage. Therefore, in order to operate the relay, it is necessary to exceed the operating voltage (about 80% or more of the rated voltage), but to maintain the operation of the relay, it is more than the return voltage (about 10 to 30% or more of the rated voltage). If the same rated coil voltage is always applied to the relay coil, useless power is consumed while maintaining the operation. The present invention suppresses coil power consumption during relay operation and suppresses temperature rise due to heat generation of the relay coil.
[0007]
Delete [0008]
Delete [0009]
Delete [0010]
Therefore, claim 1 includes a voltage generating means for supplying the two electromagnetic relay having an electromagnetic coil for opening and closing the contacts and said contact, the voltage to the electromagnetic coil of the two electromagnetic relay, the two The connection changing means connects the two electromagnetic coils in parallel to the output end of the voltage generating means at the start of the relay operation, and after a suitable time has elapsed. The present invention provides a coil drive circuit for an electromagnetic relay that is reconnected in series.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a view showing a coil driving circuit which is a first embodiment. Figure 2 is a view showing a coil driving circuit which is a second example. FIG. 3 is a diagram showing a coil driving circuit as a third example . FIG. 4 is a diagram showing a coil drive circuit according to the fourth example of the invention. FIG. 5 is a diagram showing the coil drive circuit of the first invention.
[0012]
In the explanatory diagram of the first example shown in FIG. 1, 11 is an electromagnetic relay, 12 is an electromagnetic coil for driving the electromagnetic relay, 13 is a contact, 14 is a current limiting means, R141 is a resistor, and C141 is a capacitor.
[0013]
In this embodiment, the current flowing through the electromagnetic relay 11 is controlled by the current limiting means 14 by connecting the electromagnetic relay 11 and the current limiting means 14 in series. The current limiting means 14 uses a circuit in which a capacitor C141 and a resistor R141 are connected in parallel. When a DC power supply voltage is applied to the circuit shown in FIG. 1, the capacitor C141 starts to be charged, and the current limiting means 14 receives a current. Start flowing.
[0014]
The impedance of the current limiting means 14 at this time is low, most of the power supply voltage is applied to the electromagnetic coil 12, and the electromagnetic relay 11 is attracted. Next, when the charging of the capacitor C141 is completed, no current flows through the capacitor C141, the impedance of the current limiting means 14 becomes the value of R141, and the electromagnetic coil 12 is supplied with the power supply voltage R141 and the electromagnetic coil 12. A voltage distributed with a certain impedance is applied.
[0015]
At this time, the resistance value of R141 is set so that the voltage applied to the electromagnetic relay 11 is equal to or higher than the return voltage of the electromagnetic relay 11, so that the ON state of the relay can be maintained. In addition, the time constant of the circuit composed of a resistor and a capacitor is appropriately determined so that the electromagnetic relay can be attracted and driven reliably.
[0016]
In this way, the current limiting means performs control such that when the electromagnetic coil is driven, a voltage equal to or higher than the operating voltage is applied to operate the electromagnetic relay, and after driving, a voltage equal to or higher than the return voltage is applied.
[0017]
Next, a second embodiment will be described as shown in FIG. In FIG. 2, 21 is an electromagnetic relay, 22 is an electromagnetic coil for driving the electromagnetic relay, 23 is a contact, 24 is a current limiting means, R241, R242 and R243 are resistors, C241 is a capacitor, and Tr241 is a transistor.
[0018]
In this embodiment, the current flowing through the electromagnetic relay 21 is controlled by the current limiting means 24 by connecting the electromagnetic relay 21 and the current limiting means 24 in series. The current limiting means 24 has a configuration in which a transistor, a capacitor, and a resistor are combined to control ON and OFF between the collector C and the emitter E of the transistor according to the charged state of the capacitor.
[0019]
When a DC voltage is applied to the drive circuit of FIG. 2, the collector C and the emitter E of the transistor Tr241 are turned ON by the charging current of the capacitor C241, and most of the power supply voltage is applied to the electromagnetic coil 22, and the electromagnetic relay 21 is attracted. Driven.
[0020]
When the charging of the capacitor C241 is completed, no current flows through the capacitor C241 and the collector C and the emitter E of the transistor 241 are turned off. As a result, the impedance of the current limiting means 24 is equal to R243.
[0021]
The supply voltage of the electromagnetic coil 22 is a voltage obtained by dividing the power supply voltage by the R243 and the electromagnetic coil 22. At this time, R243 is set so that the voltage applied to the electromagnetic coil 22 is equal to or higher than the return voltage of the electromagnetic relay 21. In addition, the time constant of the circuit using resistors and capacitors is appropriately determined so that the transistor is cut off after the electromagnetic relay is driven.
[0022]
Thus, the power limiting means 24 performs current control such that the electromagnetic relay is driven by applying a voltage equal to or higher than the relay operating voltage when the electromagnetic relay is driven, and a voltage of about the return voltage is applied after the driving. According to the first and second inventions described above, the current consumption can be reduced by the current limiting means while the operation of the power relay is maintained, so that the power consumption can be reduced and the amount of heat generated can be reduced.
[0023]
Next, in the figure showing a coil drive circuit as a third example shown in FIG. 3, 31 is an electromagnetic relay, 312 is an electromagnetic coil, 313 is a contact, 32 is a voltage generating means, and 33 is a generated voltage changing means. , 33d are generated voltage control units. A switching power supply that changes the generated voltage between a and c according to the potential at the reference potential point b is used as the voltage generating means 33, and resistors R333 and R334, a capacitor C331, and a transistor Tr331 are combined in the generated voltage control unit 33d. Thus, a voltage is applied to the base B of the transistor Tr331 in accordance with the charged state of the capacitor C331, and the switching operation is performed between the collector C and the emitter E of the transistor. The generated voltage changing means 33 changes the voltage between ac so that the potential at point b with respect to point c is always constant.
[0024]
Therefore, the voltage generating means 32 operates as follows. When a DC voltage is applied to the circuit shown in FIG. 3, immediately after the voltage is applied, a current flows through the base B of the Tr 331 through the C 331, the collector C and the emitter E of the Tr 331 are turned on, and R 332 and R 333 are connected in parallel. As a result, the voltage dividing ratio of resistance between bc with respect to ac becomes low.
[0025]
Therefore, the generated voltage changing means 33 controls the voltage between ac so that the voltage between bc becomes the constant value.
[0026]
Next, when charging of C331 is completed, current stops flowing to the base B of Tr331, and when the collector C and emitter E of Tr331 are turned OFF, the resistance between bc becomes only R332, and the amount of bc relative to ac The pressure ratio is high.
[0027]
Therefore, the generated voltage changing means 33 controls the voltage between ac to be lower than the previous state so that the voltage between bc becomes a constant value in the previous period.
[0028]
Therefore, the voltage when Tr331 is ON is the operating voltage of the electromagnetic coil 312. If the voltage when Tr 331 is OFF is about the holding voltage, the electromagnetic coil 312 can initially perform a suction operation at a high voltage, and can then be sucked and held at a lower voltage.
[0029]
Note that the charging time constant of C331 is set to about the time for which the electromagnetic coil 312 is sufficiently attracted. In the example of FIGS. 1 and 2, the resistor R144 or R243 also consumes power and generates heat while the electromagnetic coil is in the holding state, but in the example of FIG. Since a high-efficiency DC-DC converter or the like can be used and there is no extra heat generating part such as R144 or R243, the amount of heat generation as a whole can be further suppressed.
[0030]
Next, in a diagram showing a coil driving circuit as a fourth example shown in FIG. 4, 41 is an electromagnetic relay, 42 is an electromagnetic coil for driving the electromagnetic relay, 43 is a contact, 44 is a voltage generating means, and 45 is an electromagnetic Relay opening / closing instruction means 40d is a generated voltage changing means. A switching power supply is used as the voltage generating means 44, and a microcomputer is used as the opening / closing instruction means of the 45 electromagnetic relays. A combination of resistors R411, R412, R413, and transistors Tr411, Tr412 are combined with the generated voltage changing means 40d to switch ON / OFF between the electromagnetic relay open / close instruction means 45 and the collector C and emitter E of Tr411, Tr412. It has become. The voltage change between a and c due to the ON / OFF operation between the collector C and the emitter E of the Tr 412 is the same as the description of FIG. 45 is an electromagnetic relay open / close instruction means for controlling ON / OFF of the electromagnetic relay 41. A signal is output to the base B of the Tr411 to turn ON / OFF between the collector C and the emitter E, and to the electromagnetic coil 42. Energization is controlled.
[0031]
The electromagnetic relay open / close instruction means 45 generates an ON operation instruction signal for Tr 411, and at the same time, Tr 412 generates an ON signal for an appropriate period of time, and then turns OFF. Therefore, when the electromagnetic coil 42 is attracted by the output of the opening / closing instruction means of the electromagnetic relay, the voltage between ac is high, and the voltage between ac can be controlled low after a certain time thereafter. The power consumption and heat generation of the electromagnetic coil can be suppressed by setting the operating voltage to be equal to or higher than the operating voltage at the time of suction 42 and higher than the holding voltage after suction. The electromagnetic relay open / close instruction means 45 is constituted by a microcomputer device, a simple electronic circuit, or the like.
[0032]
FIG. 5 shows an example in which two electromagnetic relays are simultaneously ON / OFF controlled in the embodiment of the first invention. In FIG. 5, 511 and 512 are electromagnetic relays, 5112 and 5122 are electromagnetic coils for driving the electromagnetic relays, 5113 and 5123 are contacts, 521 and 522 are connection changing means, and D51 is a diode. The connection changing means of 521 and 522 is configured to perform a switching operation by combining resistors R5211, R5221, capacitors C5211, C5221, and transistors Tr5211, Tr5221.
[0033]
When a direct current voltage is applied to the circuit of FIG. 5, charging starts in the capacitors C5211, C5221 provided in the connection changing units 521, 522. Thereby, a current flows through the base B of Tr 5211 and Tr 5221, and Tr 5211 and Tr 5221 are turned on.
[0033]
At that time, the DC voltage is applied to the electromagnetic coils 5122 and 5112 as they are. If the voltage applied at this time is set to be equal to or higher than the operating voltage of the electromagnetic relay, the electromagnetic relay is driven for suction.
[0034]
Next, when charging of the capacitors C5211, C5221 is completed, no current is input to the base of each transistor, and therefore the collector C and emitter E of each transistor are in the OFF state. At this time, the electromagnetic coils 5112 and 5122 are connected in series via the diode D51, that is, the applied DC voltage is divided by the electromagnetic coils 5112 and 5122 so that the divided voltage is equal to or higher than the return voltage. If so, the contacts 5113 and 5123 of the electromagnetic relay can be held in the ON position. Therefore, the applied voltage of the electromagnetic coil in the holding state is lowered to suppress power consumption and heat generation.
[0035]
Since the voltage change circuit is configured using a resistor, a capacitor, a transistor circuit, etc., and the time constant at the time of charging is appropriately set according to the driving time of the electromagnetic relay, the voltage to the electromagnetic relay is An economical circuit can be provided, requiring few separate parts to make the change.
[0036]
In Example 3, the transistor base of the voltage change circuit can be directly controlled from a microcomputer or the like, so that the number of parts can be reduced and the relay can be driven at an arbitrary timing.
[0037]
As described above, the applied voltage to the electromagnetic coil is initially increased to operate the electromagnetic coil, and then reduced to such an extent that the electromagnetic coil can be held, thereby suppressing the power consumption of the electromagnetic coil without impairing the operation of the relay. As a result, the heat generation of the electromagnetic coil provided in the electromagnetic relay can be reduced. Therefore, it becomes possible to suppress the temperature rise of the electronic components used together with the relay in the device, and it is not necessary to use expensive components having a high operating temperature upper limit for the used components.
[0038]
【The invention's effect】
As described above, according to the present invention, it is possible to suppress the power consumption of the electromagnetic coil without affecting the energization and switching performance of the relay contact, and to suppress the temperature rise in the device using the relay. .
[Brief description of the drawings]
[1] The coil drive circuit of a first diagram showing a coil driving circuit is an example of FIG. 2 is a diagram [3] showing the coil drive circuit is a second example is a third example INVENTION Fig. 4 is a diagram showing a coil drive circuit according to a fourth example . Fig. 5 is a diagram showing a coil drive circuit according to the first invention.
11, 21, 31, 41, 511, 512 Electromagnetic relays 12, 22, 42, 5112, 5122 Electromagnetic coils 13, 23, 43, 5113, 5123 Contacts 14, 24 Current limiting means R141, R241, R242, R243, R331, R332, R333, R334, R411, R412, R413, R5211, R5221 Resistors C141, C241, C331, C5211, C5221 Capacitors
Tr241, Tr331, Tr411, Tr412, Tr5211, Tr5221 Transistors 32, 44, 53 Voltage generating means 33, 40d Generated voltage changing means 33d Transistor drive circuit unit 45 Electromagnetic relay switching instruction means 521, 522 Connection changing means D51 Diode

Claims (1)

Two electromagnetic relays having contacts and electromagnetic coils for opening and closing the contacts; voltage generating means for supplying a voltage to the electromagnetic coils of the two electromagnetic relays; and electromagnetic coils of the two electromagnetic relays; Consists of connection changing means for voltage generating means, which connects two electromagnetic coils in parallel to the output end of the voltage generating means at the start of relay operation and reconnects them in series after an appropriate time. A coil drive circuit for an electromagnetic relay.

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