JP3524153B2 - Power switch circuit for washing machines, etc. - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power switch for a washing machine or the like for driving and controlling a relay as a power switch provided in a power line of a load in response to an operation of a push switch for powering on or powering off. Regarding the circuit.

[0002]

2. Description of the Related Art An example of a power switch circuit of this type is shown in FIG. In FIG. 5, a load such as a motor (not shown) is connected between the power supply lines 2 and 3 derived from the AC power supply 1. The relay switch 4 a of the relay 4 is provided on the one power supply line 2. A series circuit including a relay coil 4b of the relay 4 and an NPN transistor 5 is connected between the DC power supply terminal V and the ground. A PNP transistor 6 and a resistor 7 are provided between the base of the transistor 5 and the DC power supply terminal V.
A series circuit consisting of and is connected. The base of the transistor 6 is connected to the port 10a of the microcomputer 10 via the resistors 8 and 9. In the microcomputer 10, an NPN type transistor 11 for setting the voltage level of the port 10a to high level or low level is provided.

A normally open push switch 12 for turning off the power source is connected between the DC power supply terminal V and the intermediate connection point of the resistors 8 and 9, and the intermediate connection point is the microcomputer 10. It is connected to port 10b. In addition, the normally open push switch 13 for powering on
Is connected between the DC power supply terminal V and the port 10c of the microcomputer 10.

In the above structure, when the push switch 13 for powering on is turned on, the port 10c of the microcomputer 10 becomes high level, the microcomputer 10 recognizes the on operation of the push switch 13, and the transistor 11 is turned on. Is turned on to bring the port 10a to a low level. As a result, the transistor 6 is turned on and the transistor 5 is turned on, so that the relay coil 4b is energized and driven, so that the relay switch 4a is turned on (that is, the power switch is turned on).

On the other hand, when the push switch 12 for turning off the power is turned on while the relay switch 4a is turned on, the intermediate connection point between the resistors 8 and 9 becomes high level, so that the transistor 6 is turned on. At the same time as it is turned off, the transistor 5 is turned off, so that the relay coil 4b is cut off and the relay switch 4a is turned off (that is, the power switch is turned off). At the same time, the port 10b of the microcomputer 10 becomes high level, and the microcomputer 10 recognizes the ON operation of the push switch 12 and turns off the transistor 11 to turn the port 10b on.
Set a to high level. As a result, the off state of the transistor 6 and the off state of the transistor 5 are held, so that the relay switch 4a is held off (that is, the power switch is off).

[0006]

However, in the above conventional configuration, if the microcomputer 10 runs away for some reason and the port 10a remains at the low level while the power is on, the power is turned off. Even if the push switch 12 for the power switch is turned on, the power may not be turned off. Specifically, when the push switch 12 for powering off is turned on, the intermediate connection point between the resistors 8 and 9 becomes high level and the transistors 6 and 5 can be turned off while the push switch 12 is turned on. However, when the operation of the push switch 12 is stopped, the port 10a of the microcomputer 10 remains at the low level, and the transistors 6 and 5 are turned on.

Therefore, an object of the present invention is to provide a washing machine or the like in which the power can be surely turned off by operating the push switch for turning off the power even if the microcomputer as the control means runs out of control. To provide a power switch circuit.

[0008]

A power supply switch circuit for a washing machine or the like according to the present invention includes a relay provided in a power supply line of a load, and a first transistor for switching the relay. The first transistor And a second transistor for controlling on / off of the second transistor, a series circuit for controlling on / off of the second transistor and including a normally-closed push switch for turning off the power source and a thyristor, and turning on the thyristor. Control means including a power-on normally-open push switch, and supplying a driving DC voltage to the first transistor and the thyristor when receiving an on-switch signal from the power-on normally-open push switch It is characterized by being equipped with.

In the case of this configuration, the thyristor includes a DC voltage circuit for generating a DC voltage for driving the thyristor, which is provided with a capacitor for preventing an instantaneous power failure, and an instantaneous power failure detecting means for detecting an instantaneous power failure of the power source. The control means stops the supply of the drive DC voltage to the first transistor and continues to supply the drive DC voltage to the thyristor when the instantaneous power failure is detected by the instantaneous power failure detection means. Then, it is preferable to control the supply of the driving DC voltage to the first transistor again when the power is restored. Further, it is more preferable that a capacitor is connected in parallel to the thyristor. Further, a current transformer for detecting a current flowing through the power supply line is provided, and the control means is based on a detection output from the current transformer, an ON / OFF operation state of the relay and a normally closed push-button for turning off the power supply. It is conceivable that the switch is configured to judge the operating state of the switch.

[0010]

According to the above means, when the power source, that is, the relay is turned on, when the normally open push switch for turning on the power source is turned on, the control means supplies the driving DC voltage to the first transistor and the thyristor, respectively. The thyristor is turned on at the same time. As a result, the second transistor is turned on, the first transistor is turned on, and the relay is turned on. When the normally closed push switch for turning off the power is operated while the relay is on, the thyristor is cut off.
The transistor is turned off, the first transistor is turned off, and the relay is turned off. In this case, even if the control means runs away, the thyristor can be turned off by operating the normally-closed push switch for turning off the power, and therefore the relay, that is, the power supply can be turned off reliably.

Further, in the case of the above construction, the DC voltage circuit for generating the DC voltage for driving the thyristor is provided with the capacitor for the instantaneous power failure, and the instantaneous power failure detection means for detecting the instantaneous power failure of the power supply is provided. When the power failure detection means detects an instantaneous power failure, the supply of the driving DC voltage to the first transistor is stopped, and the driving DC voltage is continuously supplied to the thyristor.
With a configuration that controls the supply of the driving DC voltage to the transistor, the relay can be automatically turned on again when the power is restored, even if an instantaneous power failure occurs, which is convenient for the user. It will be a good composition.

In the above structure, if the normally-closed push switch for turning off the power is momentarily turned off by an external force such as shock or vibration, the relay is turned off, and the normally-open type switch for turning on the power is turned on. The relay cannot be turned on unless the push switch is operated. On the other hand, if a capacitor is connected in parallel to the thyristor, even if the normally-closed push switch for turning off the power may be accidentally turned off accidentally, current will flow in the thyristor due to the charge stored in the capacitor. Since the flow continues, the relay can be kept in the ON state, and it is possible to prevent the relay from being turned off against the user's intention.

Further, in the above construction, since the normally closed push switch for turning off the power source is connected in series with the thyristor, the switch signal of the normally closed push switch cannot be given to the control means, and the control means is the normally closed type. It cannot be determined whether the push switch has been operated.
On the other hand, a current transformer that detects the current flowing in the power supply line is provided, and the control means controls the ON / OFF operation state of the relay and the normally closed push switch for powering off based on the detection output from the current transformer. Since the operating state is determined, the control means can reliably determine whether or not the normally closed push switch has been operated.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a fully automatic washing machine will be described below with reference to FIGS.
First, in FIG. 1 showing the electrical configuration of the fully automatic washing machine,
Between the power supply lines 22 and 23 derived from the AC power supply 21, for example, a motor 2 for washing and dehydrating operation is used as a load.
4, an electromagnetic water supply valve 25, and a motor drain valve 26 are connected in parallel. The motor 24 is composed of, for example, a condenser motor capable of rotating in the forward and reverse directions. A triac 27 is connected between the forward rotation terminal 24a and the power supply line 22, and the reverse rotation terminal 24b and the power supply line are connected. A triac 28 is connected to the terminal 22. A capacitor 29 is connected between the terminals 24a and 24b.

Further, the electromagnetic water supply valve 25 has a structure in which the triac 30 connected in series connects and disconnects electricity. Further, the motor-type drain valve 26 is configured to be electrically connected and disconnected by a triac 31 connected in series.
The relay switch 32a of the relay 32 is provided on the one power supply line 22. In order to detect whether or not the relay switch 32a is turned on, a detection resistor 33 is connected between the power supply lines 22 and 23 in parallel with each of the loads, and a current is changed to a current path of the detection resistor 33. A container 34 is provided.

On the other hand, a DC power supply circuit 35 is connected between the power supply lines 22 and 23. This DC power supply circuit 35
Is composed of a transformer 36, a full-wave rectifier circuit 37, and a smoothing capacitor 38. One end of the smoothing capacitor 38 serves as a DC voltage terminal Vpow, and the smoothing capacitor 3
The other end of 8 is grounded. A constant voltage circuit 39, which is a direct current voltage circuit, is provided at both ends of the smoothing capacitor 38.
Are connected. The constant voltage circuit 39 includes an NPN type transistor 40, a zener diode 41, a resistor 42, and a capacitor 43 as a countermeasure against instantaneous blackout, and the emitter of the transistor 40 is a DC voltage terminal Vcc.
Has become. The constant voltage circuit 39 is configured so that the output voltage can be maintained at a constant voltage by the charge charged in the capacitor 43 when an instantaneous power failure occurs.

Further, the gates of the triacs 27, 28, 30, 31 for disconnecting and electrically connecting the loads are, for example, ports 44a-4 of the microcomputer 44 which is a control means.
It is connected to 4d. This microcomputer 44
Has a function of controlling the entire washing operation of the fully automatic washing machine, and stores a control program therefor in an internal memory. The microcomputer 44 controls ON / OFF of each of the triacs 27, 28, 30, 31 to turn the motor 24 forward or reverse, or turn off the power, turn off the electromagnetic water supply valve 25, and turn off the motor drain valve 26. It is configured to be able to cut off electricity.

A resistor 45 is provided between the DC voltage terminal Vpow of the DC power supply circuit 35 and the port 44e of the microcomputer 44, and the relay coil 3 of the relay 32.
2b and a first transistor 46, for example an NPN type transistor, are connected in series. A resistor 4 is provided between the base and the emitter of the transistor 46.
7 is connected. A diode 48 having the illustrated polarity is connected to both ends of the relay coil 32b.
Further, the base of the transistor 46 and the constant voltage circuit 39
A resistor 49 and a second transistor 50, which is, for example, a PNP type transistor, are connected in series between the DC constant voltage terminal Vcc and the DC constant voltage terminal Vcc. A resistor 51 is connected between the base of the second transistor 50 and the DC constant voltage terminal Vcc.

Between the base of the second transistor 50 and the port 44f of the microcomputer 44, a series circuit including a power-off normally closed push switch 52, a resistor 53, and a thyristor 54 is connected. . Here, the intermediate connection point between the push switch 52 and the resistor 53 and the port 44f of the microcomputer 44.
A capacitor 55 is connected between and. In this case, the capacitor 55 is connected to the thyristor 54 in parallel.

Between the gate of the thyristor 54 and the DC constant voltage Vcc, a resistor 56, a diode 57 of the polarity shown, and a normally open push switch 5 for turning on the power supply.
A series circuit consisting of 8 is connected. Between the intermediate connection point between the resistor 56 and the diode 57 and the ground, a series circuit including a capacitor 59 and a resistor 60 and a resistor 61 are provided.
And are connected in parallel. A resistor 62 is connected between the gate of the thyristor 54 and the port 44f of the microcomputer 44.

Furthermore, the intermediate connection point between the normally open push switch 58 and the diode 57, and the microcomputer 44.
Between the port 44g and the
Are connected. A resistor 64 is connected between the port 44g of the microcomputer 44 and the ground.

On the other hand, one end of the current transformer 34 is connected to the port 44h of the microcomputer 44 via the diode 65 of the illustrated polarity, and the other end is grounded. A resistor 66 is connected to both ends of the current transformer 34. Further, the port 44 of the microcomputer 44
A capacitor 67 is connected between h and ground.

Further, a portion of the power supply lines 22 and 23 near the AC power source 21 is provided with an instantaneous blackout detection circuit 68, which is an instantaneous blackout detection means. This momentary power failure detection circuit 68 detects the momentary power failure of the AC power supply 21,
The detection signal is sent to the port 44 of the microcomputer 44.
It is configured to give to i. Further, the microcomputer 44 has transistors 44j and 44k therein to bring its ports 44e and 44f to a high level or a low level. In this case, when the microcomputer 44 turns on the transistor 44j, the port 44e becomes low level and the transistor 4j
When 4j is turned off, port 44e goes high,
When the transistor 44k is turned on, the port 44f becomes low level, and when the transistor 44k is turned off, the port 44f becomes high level.

Now, the normally closed push switch 5 described above
2 and the specific configuration of the normally open push switch 58 will be described. The push switches 52 and 58 are push switches having the same mechanical structure.
This push switch will be described with reference to FIGS. 2 and 3. First, in FIG. 2, the push switch 69
In the case 70, a movable contact support plate 71 made of a conductive material is disposed so as to be capable of swinging and deforming in the vertical direction with the left end as a fulcrum. The movable contact support plate 71 is urged by a movable spring 72 so as to swing and deform upward (see FIG. 2). The movable contact support plate 71 is configured so as to swing and deform downward when the operator 73 is pushed in. Movable contacts 74, 74 are provided on the upper and lower surfaces of the right end of the movable contact support plate 71. Further, in the case 70, two fixed contacts 75 and 76 are provided so as to come into contact with and separate from the movable contacts 74 and 74 of the movable contact support plate 71. Furthermore, the lower surface of the case 70 has three
The individual terminals 77, 78, 79 are provided in a protruding manner. Among them, the terminal 77 is electrically connected to the movable contact support plate 71, the terminal 78 is electrically connected to the fixed contact 75, and the terminal 79 is electrically connected to the fixed contact 76. There is.

In this case, the push switch 69 is represented by an electric circuit as shown in FIG. 3. The common contact C shown in FIG. 3 corresponds to the terminal 77, and the normally open contact A corresponds to the terminal 78. The normally closed contact B corresponds to the terminal 79. That is, when the push switch 69 is used as the normally closed push switch 52, the terminals 77 and 79 are used, and when it is used as the normally open push switch 58, the terminal 77 is used.
And the terminal 78 may be used.

Then, as shown in FIG. 4, at the right end of the operation panel 80 of the fully automatic washing machine, the normally closed push switch 52 and the normally open push switch 58 having the above-described structure are provided.
Are arranged side by side as an “off” switch key 81 for turning off the power and an “on” switch key 82 for turning on the power. In this case, the operators 73 of the normally closed push switch 52 and the normally open push switch 58 are covered with a waterproof sheet that can be pushed. The waterproof sheet portion corresponding to each operator 73 serves as the “off” switch key 81 and the “on” switch key 82. The operation panel 80 includes various operation switches for setting washing conditions and the like (course, running time, etc.), and various displays for displaying the set washing conditions and the running process. Is provided.

Next, the operation of the above configuration will be described. First,
The operation when the power is turned on will be described. in this case,
A normally open push switch 58 for the operator to turn on the power.
When the "ON" switch key 82 is pressed to turn it on, the port 44g of the microcomputer 44 goes high, and the microcomputer 44 recognizes that the normally open push switch 58 has been turned on, and the transistor 44j is turned on. And 44k on, port 44e
And 44f to low level. At the same time, when the normally open push switch 58 is turned on, a gate current flows through the thyristor 54, so that the thyristor 54 is turned on.
When the thyristor 54 is turned on, the base current of the second transistor 50 is turned on and flows, and the second transistor 50 is turned on. Then this second
When the transistor 50 is turned on, the base current of the first transistor 46 is turned on and flows, and the first transistor 46 is turned on.

As a result, since the relay coil 32b is energized and driven, the relay switch 32a is turned on and the power is turned on. Then, even if the operator stops the ON operation of the normally open push switch 58 (even if the normally open push switch 58 returns to OFF), the thyristor 54
Is kept on, the relay switch 32a is kept in the on state, that is, the power-on state.

Next, the operation when the power is turned off will be described. In this case, when the operator pushes the normally closed push switch 52 (“OFF” switch key 81) for turning off the power in the state where the power is turned on as described above to turn off, the thyristor 54 is cut off. As a result, the base current of the second transistor 50 is turned off, and the second transistor 50 is turned off.
Then, by turning off the second transistor 50, the base current of the first transistor 46 is turned off, and the first transistor 46 is turned off. As a result, since the relay coil 32b is cut off, the relay switch 32a is turned off and the power is turned off.

In this case, even if the operator stops the pushing operation of the normally closed push switch 52 (even if the normally closed push switch 52 is turned back on), no gate current is applied to the thyristor 54. The off state is retained. Therefore, the off state of the relay switch 32a, that is, the off state of the power source is maintained.

In addition, as described above, the relay switch 32
When a is turned off and the power is turned off, no current flows through the detection resistor 33, and this is done by the microcomputer 4
4 is configured to detect through the current transformer 34. Upon this detection, the microcomputer 44 turns off the relay switch 32a, that is, the normally closed push switch 5
It is possible to recognize that there has been a pressing operation of 2 (“off” switch). When the microcomputer 44 recognizes that the normally closed push switch 52 (“off” switch) has been pressed, the internal transistors 44j and 44k are turned off, and the port 44 is turned off.
It is configured to bring e and 44f to the high level. Also by this control, the thyristor 54 and the first transistor 46 are cut off (turned off).

Here, even if the microcomputer 44 runs away for some reason and keeps the ports 44e and 44f at a low level, as described above, the normally closed push switch 52 ("off" switch) is used.
By pushing in, the thyristor 54 and the first transistor 46 can be surely turned off (OFF), and the relay switch 32a can be turned off.

By the way, in the case of the above-mentioned structure, once the thyristor 54 and the first transistor 46 are turned off (OFF) and the relay switch 32a is turned off, the normally open push switch 58 (the "ON" switch) is turned on. ) Is configured so that the power cannot be turned on unless you push it in. Therefore, for example, when an instantaneous power failure occurs, the thyristor 54 and the first transistor 46 are cut off (turned off), and the relay switch 32a is turned off,
Even if the power is immediately restored, the microcomputer 44 has a configuration in which the relay switch 32a (power supply) cannot be turned on again, and thus the configuration may not be very convenient for the user.

On the other hand, in this embodiment, the constant voltage circuit 39 for generating the DC voltage for driving the thyristor 54 is provided with the capacitor 43 as a countermeasure against the instantaneous power failure, and the AC power supply 21 is used.
The momentary power failure detection circuit 68 for detecting the instantaneous power failure is provided, and when the microcomputer 44 detects the momentary power failure of the power source, the microcomputer 44 turns off the internal transistor 44j and sets the port 44e to the high level. , The supply of the driving DC voltage to the first transistor 46 is stopped, the internal transistor 44k is continuously turned on to keep the port 44f at the low level, and the driving DC voltage is continuously supplied to the thyristor 54. ing. As a result, the supply of the driving DC voltage to the first transistor 46 is stopped, so that the first transistor 46 is turned off and the relay switch 32a is turned off.
At this time, the thyristor 54 continues to be turned on by the charge stored in the capacitor 43 of the constant voltage circuit 39, and the base current of the first transistor 46 continues to be turned on.

After this, the power is immediately restored to detect the instantaneous power failure detection circuit 68.
When power recovery is detected by the microcomputer 44,
Turns on transistor 44j to turn on port 44e
Is set to a low level, and the supply of the driving DC voltage to the first transistor 46 is restarted. Due to this restart, the thyristor 54 is continuously turned on, and the base current of the first transistor 46 is continuously turned on. Therefore, the first transistor 46 is turned on and the relay switch 32a is turned on again. There is. Thus, even if an instantaneous power failure occurs, when the power is restored, the power supply (relay switch 32a) can be automatically turned on, which is convenient for the user.

Further, in the above structure, the normally closed push switch 52 for turning off the power may be momentarily turned off by some external force such as shock or vibration. In such a case, if the thyristor 54 is turned off by the momentary off operation of the normally closed push switch 52, the relay switch 32a (power supply) is turned off by turning off the thyristor 54.
Is turned off, and the relay switch 32a cannot be turned on unless the normally-open push switch 58 for turning on the power is operated, which again causes a problem of poor usability.

On the other hand, in this embodiment, since the capacitor 54 is connected in parallel to the thyristor 54, even if the normally-closed push switch 52 for turning off the power may be momentarily turned off, the capacitor Since the current continues to flow in the thyristor 54 due to the charge stored in 54, the relay switch 32a can be held in the ON state,
It is possible to prevent the relay switch 32a from being turned off against the intention of the user, and the usability is improved accordingly.
In the case of the above embodiment, the capacity of the capacitor 54 is such that the current flowing through the thyristor 54 (thyristor holding current) can be held when the normally closed push switch 52 is turned off for about 0.2 to 0.3 seconds or less. It has become a capacity. Therefore, the user (operator) can operate the normally closed push switch 52.
Since the time for turning off the switch is about 0.5 seconds, when the user turns off the normally closed push switch 52 with the intention of turning off the power, the thyristor 54 and thus the relay switch 32a are surely turned off. be able to.

In the above embodiment, the constant voltage circuit 39 is provided with the capacitor 43 for the countermeasure against the instantaneous power failure, and the AC power supply 2 is used.
Although the instantaneous blackout detection circuit 68 for detecting the instantaneous blackout of No. 1 is provided, the above configuration is not necessarily provided and may be omitted if no countermeasure against the instantaneous blackout is required. Further, the capacitor 54 connected in parallel to the thyristor 54 is not an absolutely necessary structure, but the capacitor 54 may be turned off by the momentary off operation of the normally closed push switch 52.
May be omitted. Further, in the above embodiment,
Although the thyristor 54 is used, a triac may be used instead. Furthermore, in the above embodiment, the present invention is applied to a fully automatic washing machine, but the present invention is not limited to this.
It may be applied to a tub-type washing machine or a clothes dryer.

[0039]

As is apparent from the above description, the present invention includes a relay provided on the power supply line of the load and a first transistor for switching the relay,
A second transistor for controlling on / off of the first transistor, and a series circuit for controlling on / off of the second transistor, the series circuit including a normally-closed push switch for powering off and a thyristor, and A normally-on push switch for turning on the thyristor is provided, and when the on-switch signal is received from the normally-open push switch for turning on the power, the driving DC voltage is supplied to the first transistor and the thyristor, respectively. Since the control means is provided, even if the control means runs out of control, the power can be surely turned off by turning off the thyristor by pushing in the push switch for turning off the power. It has an excellent effect.

Further, in the case of the above construction, the DC voltage circuit for generating the DC voltage for driving the thyristor is provided with the capacitor for the instantaneous power failure, and the instantaneous power failure detecting means for detecting the instantaneous power failure of the power supply is provided. When the power failure detection means detects an instantaneous power failure, the supply of the driving DC voltage to the first transistor is stopped, and the driving DC voltage is continuously supplied to the thyristor.
It is configured to control so as to restart the supply of the driving DC voltage to the transistor. As a result, when an instantaneous power failure occurs, the relay can be automatically turned on again when the power is restored, and the usability can be improved.

Further, since the capacitor is connected in parallel to the thyristor, even if the normally-closed push switch for turning off the power may be accidentally turned off by mistake, a current will flow in the thyristor due to the charge of the capacitor. Because it keeps flowing, you can keep the relay on.
It is possible to prevent the relay from being turned off accidentally against the intention of the user.

Furthermore, a current transformer for detecting the current flowing in the power supply line is provided, and the control means controls the ON / OFF operation state of the relay and the normally closed push-button for powering off based on the detection output from the current transformer. Since it is configured to determine the operating state of the switch, the control means can reliably determine whether or not the normally closed push switch has been operated.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of the present invention.

[Figure 2] Vertical side view of push switch

FIG. 3 is an electric circuit diagram of a push switch.

FIG. 4 is a top view of the operation panel.

FIG. 5 is an electric circuit diagram showing a conventional configuration.

[Explanation of symbols]

21 is an AC power supply, 22 and 23 are power lines, 24 is a motor (load), 25 is an electromagnetic water supply valve (load), 26 is a motor drain valve (load), 32 is a relay, 32a is a relay switch, and 32b is a relay coil. , 33 is a detection resistor, 34 is a current transformer, 35 is a DC power supply circuit, 39 is a constant voltage circuit (DC voltage circuit), 43 is a capacitor, 44 is a microcomputer (control means), 46 is a first transistor, 50 Is a second transistor, 52 is a normally closed push switch,
54 is a thyristor, 55 is a capacitor, 58 is a normally open push switch, 68 is an instantaneous blackout detection circuit (instantaneous blackout detection means), 69 is a push switch, 71 is a movable contact support plate, 73 is an operator, and 74 is a movable contact. , 75 and 76 are fixed contacts, and 80 is an operation panel.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01H 9/54 D06F 39/00 H03K 17/73

Claims (4)

(57) [Claims] 1. A relay provided in a power supply line of a load, a first transistor for switching the relay, a second transistor for ON / OFF controlling the first transistor, and an ON / OFF control for the second transistor. And a series circuit composed of a normally closed push switch and a thyristor for turning off the power, a normally open push switch for turning on the thyristor, and a normally open push switch for turning on the power. A power supply switch circuit for a washing machine or the like, which comprises a control means for supplying a driving DC voltage to the first transistor and the thyristor when receiving an on-switch signal from the device. 2. A capacitor provided for a DC voltage circuit for generating a DC voltage for driving the thyristor, which is provided to a DC voltage circuit, and an instantaneous power failure detection unit for detecting an instantaneous power failure of the power supply, the control unit comprising: When the momentary power failure is detected by the momentary power failure detection means, the supply of the driving DC voltage to the first transistor is stopped, the driving DC voltage is continuously supplied to the thyristor, and the power is restored. The power supply switch circuit for a washing machine or the like according to claim 1, wherein the supply of the driving DC voltage to the first transistor is restarted when this occurs. 3. A power switch circuit for a washing machine or the like according to claim 1, wherein a capacitor is connected in parallel to the thyristor. 4. A current transformer for detecting a current flowing through the power supply line is provided, and the control means is an ON / OFF operation state of the relay and a normally closed type for turning off the power supply based on a detection output from the current transformer. The power switch circuit for a washing machine or the like according to claim 1, wherein the operating state of the push switch is determined.