JPH0614418Y2 - Voltage switching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial application field" The present invention relates to a voltage switching device used for switching and supplying a holding voltage after supplying an operating voltage to a plunger solenoid, for example.

"Prior Art" Plunger solenoids require a relatively large voltage (current) to operate. When the operating current is continuously supplied to the plunger solenoid for a long time, the plunger solenoid generates heat, so that after the operation, the voltage is switched to a low voltage (current) necessary for maintaining the operating state.

In this way, a relatively high voltage is applied during operation, and a low holding voltage is switched and supplied after operation.
It was configured as shown. That is, switch 1
When 1 is turned on, an operating current flows from the power supply 12 to the plunger solenoid 14 through the contact 13, and when the plunger solenoid 14 operates, the contact 13 is turned off by the movement of the plunger (not shown), and the resistor in parallel with the contact 13 Holding current is supplied to the plunger solenoid 14 through 15.

Alternatively, as shown in FIG. 4, when the contact 17 is turned on by the control circuit 16, the AC voltage of the AC power source 18, such as a commercial power source, passes through the normally closed side b of the switching contact 19, and further through the full-wave rectifier circuit 21. An operating current is supplied to the solenoid 14. As a result, the plunger solenoid 14
, The switching contact 19 is switched to the normally open side m by the control circuit 16, and the voltage of the AC power supply 18 whose voltage is lowered by the transformer 22 is passed through the normally open side m of the switching contact 19.
Further, through the full-wave rectification circuit 21, the plunger solenoid 1
4 is supplied.

As described above, all the conventional circuits use mechanical contacts, and when the contacts are frequently opened and closed, they have a short life and generate noise during switching.

An object of the present invention is to provide a voltage switching device that has a long life and does not generate noise.

[Means for Solving the Problems] According to the present invention, the first terminal of the AC power supply for supplying the operating voltage to the plunger solenoid and the second terminal for supplying the holding voltage lower than the operating voltage to the plunger solenoid are provided. The first zero-cross semiconductor switch and the second zero-cross semiconductor switch are respectively inserted between the terminal and the plunger solenoid, and ON and OFF signals are supplied to the input terminals of these zero-cross semiconductor switches to start the operation of the plunger solenoid. Sometimes, the AC voltage is supplied from the first terminal of the AC power supply and from the second terminal after the operation is started, and the OFF signal supplied to the input terminal of the first zero-cross semiconductor switch is kept constant for a certain period of time. When it turns off after the elapse of time, the plunger is connected to the input terminal of the second zero-cross semiconductor switch. An off signal is supplied for a fixed time shorter than the solenoid's return, and an on signal is supplied to the input terminal of the second zero-cross semiconductor switch after the elapse of the fixed time shorter than the plunger solenoid's return. With this configuration, the two zero-cross semiconductor switches are never turned on at the same time. Therefore, a serious defect that a short-circuit current flows through these zero-cross semiconductor switches and destroys these switches can be eliminated.

Further, the zero-cross semiconductor switch does not conduct when the ON signal is supplied to its input terminal, the ON signal is supplied to the input terminal, and the instantaneous level of the AC power supply voltage supplied to the switch is close to zero cross. Sometimes it is triggered for the first time to conduct electricity, so there is no risk of noise when switching the voltage, and the switch does not easily deteriorate even if the voltage is switched frequently, thus improving reliability and long life. become.

[Embodiment] FIG. 1 shows an example in which the voltage switching device according to the present invention is applied to switching between an operating voltage and a holding voltage for a plunger solenoid. The AC power supply 31 has a common terminal 32 and first and second terminals 33 and 34, and the common terminal 32 and the first and second terminals
Different voltages are generated between the terminals 33 and 34. In this example, both ends of a power source 35 such as a commercial power source have terminals 32, 3
3 and a transformer 36 between terminals 32 and 33.
Is connected to the primary side of the transformer 36 and the secondary side of the transformer 36 is connected to the terminal 3
It is connected between 2 and 34. The voltage on the primary side between the terminals 32 and 33 is a relatively high voltage for starting the operation of the plunger solenoid, for example, 100 V, and the terminal 3
The voltage on the secondary side between 2 and 34 is a holding voltage lower than the operation starting voltage for holding the operation of the plunger solenoid, for example, 50V.

A first zero-cross semiconductor switch 39 is connected between the first terminal 33 and one end 38 of the load 37, and a second zero-cross semiconductor switch 41 is connected between the second terminal 34 and one end 38 of the load 37. The other end 42 of the load 37 is the common terminal 3
Connected to 2. In this example, as the load 37, the input side of the full-wave rectification circuit 43 is connected between both ends 38 and 42 thereof, and the plunger solenoid 44 is connected to the output side of the full-wave rectification circuit 43.

In this example, the operation switch 51 is provided in parallel with the capacitor 52, and both ends of the capacitor 52 are connected to both ends of the capacitor 53 through the coils 54 and 55.
One end of 3 is grounded, the other end is connected to the power supply terminal 56, and is also connected to the gate 59 and the input terminal B of the monostable multivibrator 61 through the inverters 57 and 58. The output of the monostable multivibrator 61 is supplied to the gate 59, and the output side of the gate 59 is connected to the input terminal of the first zero-cross semiconductor switch 39.

The Q output of the monostable multivibrator 61 is supplied to the input terminal B of the monostable multivibrator 61 as a delay circuit, and the Q outputs of the monostable multivibrators 61 and 62 are supplied to the gate 63. The output of the gate 63 is supplied to the gate 64, and the output of the inverter 58 is supplied to the gate 64 through the gate 65. The output of the gate 64 is supplied to the input terminal of the second zero-cross semiconductor switch 41.

The first and second zero-cross semiconductor switches 39, 41 do not conduct when an OFF signal is supplied to their input terminals, and do not conduct when an ON signal (low level “0” in this example) is given. It is triggered when the instantaneous level of the AC voltage supplied from the device is close to zero cross, and is conductive, and is generally called a zero cross solid state relay (zero cross SSR). Gate 59,
63 and 64 each act as an OR gate.
A monostable multivibrator 62 for supplying an ON or OFF signal to the input terminal of the second zero-cross semiconductor switch 41.
The duration of the signal generated at the time of operation from the output Q of is set to be shorter than the time when the plunger solenoid that started the operation returns to the original state when the supply of the power supply voltage is cut off. ..

Next, the operation of the voltage switching device shown in FIG. 1 will be described with reference to the time chart of FIG. When the operation switch 51 is turned on, at that time t ₁ , the output of the inverter 58 becomes a low level “0” as shown in FIG. 2A, and the falling thereof triggers the monostable multivibrator 61, and its Q The output and the output are, as shown in FIGS. 2B and 2C, respectively, for a certain period of time T ₁ , high level “1” and low level “0”.
become. Therefore, during this period T ₁ , both inputs of the gate 59 are at the low level “0” and their outputs are also at the low level “0”.
During this period, the ON signal is given to the first zero-cross semiconductor switch 39, and immediately thereafter, when the instantaneous level of the output of the AC power supply 31 becomes close to zero, the switch 39 is turned ON, and for almost this period T ₁ , The first zero-cross semiconductor switch 39 is turned off after being turned on. In this example, the period T _{1 of the} ON state is the plunger solenoid 44.
Is selected for more than the time required to operate reliably.

On the other hand, at the time t ₁ when the Q output of the monostable multivibrator 61 has passed the high level period T ₁ , the monostable multivibrator 61 as a delay circuit is triggered at its falling edge,
The Q output becomes high level "1" during the period T ₂ as shown in FIG. 2E. That is, the monostable multivibrator 61
The change in the Q output (FIG. 2B) from the high level to the low level is the generation of the switching control signal, and the switching control signal is delayed by the period T ₂ and the monostable multivibrator 62 is output.
Of the switching control signal, i.e., t ₂
A switching control signal appears at the Q output of the monostable multivibrator 62 at a time point t ₃ after a period T ₂ from the second zero-cross semiconductor switch 41 is turned on by the switching control signal.

That is, while the first zero-cross semiconductor switch 39 is on, the Q output of the monostable multivibrator 61 is supplied to the gate 63 so that the second zero-cross semiconductor switch 41 does not turn on, and while the operation switch 51 is off. The output of the inverter 58 is supplied to the gate 64 through the gate 65 so that the second zero-cross semiconductor switch 41 is off.

Thus, the output of the gate 63, as shown in FIG. 2 F, change in period T _1, T the time t ₃ after a lapse of ₂ from the high level "1" to low level "0", and by the fall Both inputs of the gate 64 become low level "0", the output becomes low level "0" as shown in FIG. 2G, and the low level "0" is sent to the second zero-cross semiconductor switch 41 as a switch-on signal. Then, the second zero-cross semiconductor switch 41 is turned on.

That is, when the switching control signal is generated at time t ₂ , its inverted signal is given to the gate 59 from the output of the monostable multivibrator 61, the switch-on signal from the gate 59 is cut off, and the first zero-cross semiconductor switch 39 is turned off. is, the second zero-crossing semiconductor switch 41 is turned on with a delay than this T ₂ of the time. Therefore, when the switching control signal is issued while the first voltage is being applied from the AC power supply 31 to the load 37 through the first terminal 33, the voltage supply from the first terminal 33 is stopped and the period T ₂ Second after
The second voltage from the terminal 34 is supplied to the load 37. In this example, when the operation switch 51 is turned on, the operating voltage is applied to the plunger solenoid 44 from the first terminal 33 for the period T ₁ , and the plunger solenoid 44 operates,
The holding voltage is automatically switched and supplied from the second terminal 34 to the plunger solenoid 44.

Turning off the operation switch 51 outputs a high-level of the inverter 58 as shown in the time t ₄ in FIG. 2 A "1"
Then, the output of the gate 64 also becomes a high level "1" as shown in FIG. 2G, the switch-on signal is cut off, and the second
The zero-cross semiconductor switch 41 is turned off.

In the above description, the present invention is applied to the switching of the supply voltage to the plunger solenoid 44.
While supplying the first alternating voltage to the second alternating second voltage
The present invention can be applied to the case of supplying an AC voltage.

[Advantage of the Invention] As described above, according to the present invention, the first and second zero-cross semiconductor switches 39 and 41 are controlled to be switched to switch the AC voltage supplied to the plunger solenoid. Even if switching is performed, the switch does not easily deteriorate and a long-life product can be obtained. Further, since the semiconductor switches 39 and 41 are the zero-cross switches, the semiconductor switches 39 and 41 are turned on only during a period when the instantaneous level of the alternating voltage is small, so that noise is not generated.

Further, the first zero-cross semiconductor switch 39 is turned off,
Since the second zero-cross semiconductor switch 41 is turned on after the elapse of a certain period T ₂ , the terminals 33, 34 are switched at the time of voltage switching.
There is no danger of short-circuiting between the zero-cross semiconductor switches 39 and 41, and therefore, there is a serious drawback that a short-circuit current flows from the AC power supply 31 to these zero-cross semiconductor switches 39 and 41 and destroys these switches 39 and 41. Can be removed.

[Brief description of drawings]

FIG. 1 is a connection diagram showing an example of a voltage switching device according to the present invention, and FIG. 2 is a time chart used for explaining the operation thereof.
FIG. 3 and FIG. 4 are connection diagrams showing a conventional switching circuit for operating voltage and holding voltage for a plunger solenoid. 31: AC power supply, 33: First terminal, 34: Second terminal, 3
7: load, 39: first zero-cross semiconductor switch, 4
1: Second zero-cross semiconductor switch, 51: Operation switch, 61: Monostable multivibrator, 62: Monostable multivibrator as a delay circuit, 59: Gate that turns off the switch-on signal at the time of switching, 63: Delay switching control signal A gate that generates a switch-on signal.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ken Ito 1 170-1 Kamikawate, Gifu City, Gifu Prefecture (56) References JP-A-59-108121 (JP, A) JP-A-54-159141 (JP, U) 57-64038 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. An operating voltage is supplied to the plunger solenoid from a first terminal of the AC power supply when the operation of the plunger solenoid is started, and a second terminal of the AC power supply is operated from the operating voltage after the operation of the plunger solenoid is started. In a voltage switching device that switches the output voltage of the AC power supply so as to supply a low holding voltage to the plunger solenoid, the voltage switching device is inserted between a first terminal of the AC power supply and one end of the plunger solenoid, and is turned on at an input terminal. A first zero-cross semiconductor switch that is triggered and conducts when the instantaneous level of the AC power supply voltage supplied while a signal is applied approaches zero cross, a second terminal of the AC power supply, and one end of the plunger solenoid. Of the AC power supply voltage that is supplied when an ON signal is applied to the input terminal. A second zero-cross semiconductor switch that is triggered and conducts when the time level is near zero-cross, switch means for operating the plunger solenoid, and the first and second zero-cross semiconductor switches when the switch means is off. Circuit means for supplying an OFF signal to each of the input terminals of the first zero-cross semiconductor switch, the circuit means operating when the switch means is turned on to supply the ON signal to the input terminal of the first zero-cross semiconductor switch for a predetermined time. An OFF signal is supplied to the input terminal of the second zero-cross semiconductor switch for the same constant time, and the first zero-cross semiconductor switch is made conductive by the plunger solenoid operating voltage supplied from the first terminal of the AC power supply. A first on / off signal for supplying an operating voltage to the plunger solenoid Generating means and an input terminal of the second zero-cross semiconductor switch that operates when the off signal generated from the first on / off signal generating means is turned on after the elapse of the certain time. An OFF signal is supplied for a fixed time shorter than the plunger solenoid returning, and an ON signal is supplied to the input terminal of the second zero-cross semiconductor switch after the elapse of a constant time shorter than the plunger solenoid returning. Second ON / OFF signal generating means for electrically connecting the second zero-cross semiconductor switch with the plunger solenoid holding voltage supplied from the second terminal of the AC power source and supplying the holding voltage to the plunger solenoid. A voltage switching device comprising: