JPS5961431A - Load selector - 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 The present invention relates to a load selection device suitable for connecting two electrical devices to one electrical outlet and selecting one of the electrical devices.

Conventionally, large-capacity electric devices such as near conditioners and microwave ovens are usually connected to electrical outlets wired with dedicated wiring in a 1:1 correspondence with a wiring breaker. However, even if you want to use two electrical devices in a room or place such as an apartment where there is only one outlet with dedicated wiring, it is often not possible to easily add more dedicated wiring or outlets. For safety reasons, it is not possible to energize two electrical devices at the same time, so the user must alternately insert the plug into the same outlet and operate the device, which is very inconvenient for the user.

Therefore, the present applicant has previously proposed that by providing a switch for each branch circuit connected to one outlet, it is possible to connect two electrical devices to one outlet and select one of the electrical devices. It is requested.

However, in this proposal, since each branch circuit must be provided with a switching section and a current detection means, the cost becomes relatively high.

An object of the present invention is to provide a load selection device that solves the above-mentioned problems and enables cost reduction.

In order to achieve this object, the present invention includes a main circuit connected to a power supply, a branch circuit branched from the main circuit to which two loads are respectively connected, and a current detection means for detecting the current of the main circuit. and a high impedance initial closing detection means which is connected in parallel to one side of the double throw opening/closing section and detects the ON condition of one of the loads, and the ON condition of the one load is detected by the initial closing detection means. When the load current is not detected by the current detection means, one of the double-throw switching parts is turned on, and when the load current is detected by the current detection means after one of the double-throw switching parts is turned on, The control means maintains one of the opening/closing parts on, and turns on the other of the double-throw opening/closing parts at times other than the above.

The present invention will be explained in detail below based on illustrated embodiments.

The drawing shows one embodiment of the present invention, in which one of two loads is selected. Two branch circuits 4a and 4b branched from the main circuit 3 are provided between the power supply side terminal 1 and the load side terminals 2a and 2b, and the main circuit 3 and the branch circuit 4a
, 4b is provided with a double-throw opening/closing part 5. Double throw opening/closing part 5
is equipped with a normally open contact 6a, a normally closed contact 6b, and a common contact 6C, and also has a normally open contact 6a by excitation of the relay coil 7.
and a common contact 6C.

As this double-throw opening/closing part, a switching contact of a relay that is switched by energizing or de-energizing the relay coil 7 is used.

Loads 9a and 9b are connected to the load side terminals 2a and 2b, respectively. When the load 9a or the load 9b is energized,
A series circuit of a photocoupler 14 consisting of a resistor 11 whose impedance is higher than the impedance of the current transformer, a light emitting diode 12, and a phototransistor 13 is connected in parallel to the current flowing through the main circuit 3. The output from the photocoupler 14 is input to a monostable multivibrator 16 via a logic converter 15 equipped with a delay section.

An amplifier 17, a rectifier 18, and a comparator 19 are connected to the output side of the current transformer 10. Reference voltage generation circuit 20 generates a reference voltage for comparator 190. An AND gate 21, a D flip-flop 22, and a monostable multivibrator 23 are connected to the output side of the comparator 19. or gate 2
4 outputs a high level when a no-low level signal is input for a certain period of time from the monostable multivibrator 23, or when a low level signal is input from the initial reset unit 25, and resets the D clip-flop 22. The OR gate 26 outputs a high level signal to the switching circuit 27 when a high level signal is input to either input terminal.

The switching circuit 27 excites the relay coil 7 and turns on the normally open contact 6a by inputting a high level signal from the OR gate 26, and stops excitation of the relay coil 7 by inputting a low L/bell signal. Normally closed contact 6
Turn on b.

Next, the operation will be explained. When the relay coil 7 is not energized, the double-throw switching section 5 turns on the normally closed contact 6b and turns off the normally open contact 6a. First, when the load 9a is in the ON state, the power supply voltage is applied between the common contact 6c of the double-throw switching section 5, the resistor 11 connected in parallel between the normally open contact 6a, and the photocoupler 14. Note that the resistor 11 has a considerably higher resistance value than the invader of the load 9a (load 9a
impedance<<resistance 11).

When a power supply voltage is applied, a current flows through the light emitting diode 12 and it emits light, and the light hits the phototransistor 13 and is energized, is converted to a logic level by the logic converter 15, and is input to the monostable multivibrator 16. . A no-level signal is input from the monostable multi-pipe lake 16 to one input terminal of the AND gate 21, and to the other input terminals there are signals that are not detected by the current transformer 10, an amplifier 17, a rectifier 18, A low level signal is input through the comparator 19, and therefore /1 is input from the AND gate 21.
A high level signal is output. The switching circuit 27 energizes the relay coil 7 by inputting the signal of the level No.
The contact is switched from to the normally open contact 6a.

When the normally open contact 6a is turned on, the load 9a is energized and detected by the current transformer 10. In response to this detection signal, a signal of 7.times.Irepel is outputted from the comparator 19 via the amplifier 17 and the rectifier 18.

Due to the high level signal input, the output of the AND gate 21 becomes low level. The high level signal from the comparator 19 is input to the clock input terminal CK of the D clip-flop 22, and at this time, since the high level signal from the monostable multivibrator 16 is input to the input terminal,
The output of the output terminal Q of the D flip-flop 22 is inverted to the Kino level. Therefore, the D flip-flop 427 continues to excite the relay coil 7 and continues to energize the load 9a. Furthermore, when the load 9a changes from the energized state to the OFF state,
When the output of the comparator 19 is inverted from high level to low level, the pulse generated by the monostable multivibrator 23 is input to the input terminal R of the D flip-flop 7 block 220, and the relay coil 7 is de-energized by being reset. becomes.

Next, a case where the load 9b is in the on state will be explained. Double throw opening/closing part 5
is not switched, the load 9b is energized, and the current transformer 1
0, current is detected.

The detection signal passes through an amplifier 17 and a rectifier 18, and from a comparator 19, a signal at a level of 7.I is input to an AND gate 21, whose output becomes a low level. Furthermore, since a low level signal is input to the input terminal of the D flip-flop 22, the output from the output terminal Q of the D flip-flop 22 is at a low level. Therefore, the output of the OR gate 26 becomes a low level, the switching circuit 27 does not excite the relay coil 7, and the load 9b continues to be energized.

Next, a case where the loads 9a and 9b are in the ON state at the same time will be described.

Since the relay coil 7 is not excited, the double-throw switching section 5 turns on the normally closed contact 6b, and therefore the load 9b
is energized, and the current is detected by the current transformer 10. In response to the detection signal, a high level signal is output from the comparator 19 via the amplifier 17 and the rectifier 18, and is input to the AND gate 21 and the D flip-flop 22, respectively. Due to the high level signal input, the output of the AND gate 21 becomes low level. On the other hand, the photocoupler 14 operates due to the ON state of the load 9a, and the current of the phototransistor 13 is input to the logic converter 15. However, since the logic converter 15 is equipped with a delay section, The output is delayed for a predetermined period of time. Therefore, at the time when the output of the comparator 19 is inverted to a high level, the output of the monostable multi-bi break 16 is still at a low level, and the output of the output terminal Q of the D flip-flop 22 is held at the loan .theta. Therefore, the outputs of the two OR gates become low level, the switching circuit 27 does not excite the relay coil 7, the normally closed contact 6b continues to be turned on, and the load 9b is preferentially energized.

According to this embodiment, each one double-throw switch 5 and current transformer 10
Since the circuit can be configured by using
It is possible to reduce costs.

In the illustrated embodiment, the current transformer 10 corresponds to the current detection means, the resistor 11 and the photocoupler 14 correspond to the initial input detection means, the AND gate 21, the Dzl amplifier 22,
The monostable multi-by-break 16 and the OR gate 26 correspond to the control means of the present invention.

In this embodiment, the current transformer 10 is used to detect the current, but the present invention is not limited to this, and a current shunt may be used, and a transformer may be used instead of a resistor and a photocoupler. Note that the DC power supply section is omitted.

As explained above, according to the present invention, there is provided a double-throw opening/closing section that switches the opening and closing of two branch circuits, a high impedance initial loading detection means that detects the loaded state, and a high impedance initial loading detection means that detects the loaded state of the one load. When the load current is detected by the initial closing detection means and the load current is not detected by the current detection means, one of the double-throw opening/closing parts is turned on, and following the turning on of one of the double-throw opening/closing parts, the load current is detected by the current detection means. Since a control means is provided that keeps one of the double-throw opening/closing parts turned on when the detection is detected, and turns on the other of the double-throw opening/closing parts at other times, a circuit configuration that reduces costs can be achieved.

[Brief explanation of drawings]

The drawing is a circuit diagram showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Power supply side terminal, 3... Main circuit, 5... Double throw switching part, 7... Relay coil, 10... Transformer, 11
--Resistor, 14... Photocoupler, 21... e-and gate, 22... D-flip-flop, 27...
Tatami switching circuit. Patent applicant Minoru Nakamura, representative of Osaki Electric Industry Co., Ltd.

Claims (1)

[Claims] 1. A main circuit that connects to the power supply, a branch circuit that branches off from the main circuit and connects two loads to each, a double-throw switching section that switches the opening and closing of the two branch circuits, and a circuit that detects the current in the main circuit. a high-impedance initial-on detection means connected in parallel to one side of the double-throw switching section to detect the on-state of one of the loads; and the on-state of the one load is detected by the initial-on detection means. and when the load current is not detected by the current detection means, one of the double-throw switching parts is turned on, and when the load current is detected by the current detection means following one of the double-throw switching parts being turned on,
Keep one side of the double-throw opening/closing part turned on, and at times other than the above,
A load selection device comprising a control means for turning on the other of the double-throw opening/closing parts.