JPH08278331A - Voltage monitoring device - Google Patents

Abstract

PURPOSE: To accurately and inexpensively monitor the voltage of a commercial power supply by achieving the same electrical resistance as that of a load circuit and at the same time connecting a voltage monitoring device to the secondary coil winding side of a power supply transformer and stopping operation when the load circuit is activated and performing operation when the operation stops. CONSTITUTION: When no louver operation signal 801 for operating a louver motor 30 is inputted to a microcomputer 8, a relay operation instruction part 82 does not instruct the transmission of a conduction instruction signal 820 from an output port 821, a transistor 4 does not conduct and a connection point (m) becomes a high level for causing a transistor 6 to conduct and then a current with the same resistance as that of the relay 3 flows to a resistor 5. Also, when a signal 802 for operating the motor 30 is inputted to the computer 8, the transmission of the signal 820 from the port 821 is instructed, the transistor 4 conducts and the relay 3 is activated, the connection point (m) becomes a high level and the transistor 6 does not conduct, and no electric wave flows to the resistor 5, thus accurately and inexpensively monitoring the voltage of a power supply 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage monitoring device for monitoring the voltage of a commercial power source.

[0002]

2. Description of the Related Art The commercial power supply voltage drops below the rated voltage during the morning and evening hours when power consumption is high, and the commercial power supply voltage rises above the rated voltage during the early morning hours. Therefore,
For example, a convection fan (AC motor) that operates on commercial power
In the warm air heater having the above, the amount of warm air blown out varies depending on the voltage value of the commercial power source, which causes a problem that the user is distrusted.

In order to prevent this, the following voltage monitoring device for monitoring the voltage of the commercial power supply has been known. (A) Monitor the voltage of the commercial power supply applied to the primary winding of the power transformer. (Ii) A secondary winding for detecting the voltage of the commercial power source is provided in the power transformer, and a dedicated rectifier circuit for monitoring the voltage of the commercial power source is connected to the secondary winding. Monitor voltage. (C) The voltage of the commercial power supply is monitored based on the output voltage of the rectifier circuit connected to the secondary winding of the power transformer.

[0004]

In the above technique (a), the voltage of the commercial power source can be accurately monitored even if the state of the load connected to the secondary winding of the power transformer is switched.
A circuit configuration is provided that insulates the detection unit from the primary side, which is costly.

In the above technique (i), a secondary winding for voltage detection and a rectifier circuit are required, which is costly.
In the above technique (u), when the state of the load connected to the output side of the rectifier circuit is switched, the voltage of the commercial power supply cannot be monitored accurately.

An object of the present invention is to provide a voltage monitoring device which can monitor the voltage of a commercial power source accurately at low cost.

[0007]

In order to solve the above-mentioned problems,
The present invention employs the following configuration. (1) A power transformer in which the primary winding is connected to a commercial power source,
A rectifier circuit connected to the secondary winding of the power transformer, and a load circuit connected to the secondary winding side of the power transformer,
A voltage monitoring unit that monitors the voltage of the commercial power source based on the output voltage of the rectifier circuit, and the load circuit, which has the same electrical resistance as the load circuit and is connected to the secondary winding side of the power transformer. And a pseudo load circuit which is activated when the load circuit is deactivated.

(2) A power transformer having a primary winding connected to a commercial power source, a rectifier circuit connected to the secondary winding of the power transformer, a load connected in series to the output side of the rectifier circuit, and a first A semiconductor switch element, a pseudo load and a second semiconductor switch element connected in series to the output side of the rectifier circuit, a voltage monitoring unit that monitors the voltage of the commercial power source based on the output voltage of the rectifier circuit, and the load. And a controller having an energization instructing section for instructing to send out an energization instruction signal to the first semiconductor switch element when energizing the electric resistance of the pseudo load is the same as the electric resistance of the load, The connection point between the load and the first semiconductor switching element and the control terminal of the second semiconductor switching element are electrically connected, and the second semiconductor switching element is in a conductive state when the load is not energized. .

(3) A power transformer having a primary winding connected to a commercial power source, a rectifier circuit connected to the secondary winding of the power transformer, and a load and a semiconductor switch connected in series to the output side of the rectifier circuit. An element and a pseudo load having the same electric resistance as that of the load, which is connected to the output side of the rectifier circuit, and a voltage monitor that monitors the voltage of the commercial power source based on the output voltage of the rectifier circuit. And a controller having an energization instructing unit for instructing to send a control signal to the control terminals of the semiconductor switch element and the pseudo load circuit when energizing the load, wherein the pseudo load circuit is the control signal. Is input, the pseudo load is energized.

(4) A power transformer having a primary winding connected to a commercial power source, a rectifier circuit connected to the secondary winding of the power transformer, a relay and a first relay connected in series to the output side of the rectifier circuit. A transistor, a pseudo load and a second transistor connected in series to the output side of the rectifier circuit, a voltage monitoring unit that monitors the voltage of the commercial power supply based on the output voltage of the rectifier circuit, and based on an input signal. A microcomputer having a relay operation instructing section for instructing to send an energization instructing signal to the first transistor when determining whether or not to operate the relay and operating the relay, and the electric resistance of the pseudo load is The same as the electrical resistance of the relay, the connection point between the relay and the first transistor,
The control terminal of the second transistor is electrically connected, and the second transistor becomes conductive when the relay is inactive.

[0011]

[Action]

[Claim 1] When the load circuit is operating, the pseudo load circuit is deactivated. When the load circuit is not operating, the pseudo load circuit having the same electric resistance as the load circuit is activated. Therefore, even if the energization state to the load circuit is switched, the power consumption on the secondary winding side does not change, so that the output voltage of the rectifier circuit does not change.

[Claim 2] When the load is energized, the energization instructing unit of the controller instructs the first semiconductor element to send out the energization instructing signal. Therefore, the first semiconductor switch element becomes conductive and the load is energized. At this time, the second semiconductor switch element is turned off based on the potential at the connection point between the load and the first semiconductor element, and the pseudo load is not energized.

When the load is not energized, the energization instructing unit of the controller does not instruct the first semiconductor element to send out the energization instruction signal. Therefore, the first semiconductor switch element does not conduct, and the load is not energized. At this time, based on the potential at the connection point between the load and the first semiconductor element, the second semiconductor switching element becomes conductive and the pseudo load having the same electric resistance as the load is energized. Therefore, even if the power supply state to the load is switched, the power consumption on the secondary winding side does not change, so the output voltage of the rectifier circuit does not change.

[Claim 3] When the load is energized, the energization instructing section of the controller instructs the semiconductor switch element and the control terminal of the pseudo load circuit to send a control signal.
Therefore, the semiconductor switch element becomes conductive and the load is energized. Further, the pseudo load circuit is turned off, and the pseudo load is not energized.

When the load is not energized, the energization instructing unit of the controller does not instruct to send the control signal to the control terminals of the semiconductor switch element and the pseudo load circuit. At this time, since the semiconductor switch element is not conductive, the load is not energized. Further, the pseudo load circuit energizes the pseudo load, and the pseudo load consumes the same power as that consumed by the load when energized. Therefore, even if the power supply state to the load is switched, the power consumption on the secondary winding side does not change, so the output voltage of the rectifier circuit does not change.

[Claim 4] The relay operation instructing unit of the microcomputer determines whether or not to operate the relay based on the input signal, and when it is determined that the relay is to be operated, the first transistor of the energization instruction signal is supplied. To send to. Therefore, the first transistor becomes conductive and the relay is energized. At this time, the second transistor becomes non-conductive based on the potential at the connection point between the relay and the first transistor, and the pseudo load having the same resistance value as the relay is not energized.

The relay operation instructing unit of the microcomputer determines whether or not to operate the relay based on the input signal, and when it determines that the relay is not to operate, it does not instruct to send the energization instruction signal to the first transistor. . Therefore,
The first transistor does not conduct and the relay is not energized.
At this time, the second transistor becomes conductive based on the potential at the connection point between the relay and the first transistor, and the pseudo load having the same electric resistance as the relay is energized. Therefore, the output voltage of the rectifier circuit does not change even when the energization state of the relay is switched.

[0018]

【The invention's effect】

[Claim 1] When the load circuit operates, the pseudo load circuit does not operate, and when the load circuit stops operating, the pseudo load circuit having the same electric resistance as the load circuit operates. , The output voltage of the rectifier circuit does not change.

The voltage monitoring means monitors the voltage of the commercial power source based on the output voltage of the rectifier circuit connected to the secondary winding of the power transformer. Therefore, a secondary winding for monitoring commercial voltage and a rectifier circuit are not required, and it is not necessary to insulate the voltage monitoring means from the primary side of the power transformer. Therefore, the voltage monitoring device can accurately monitor the voltage of the commercial power source at low cost.

[Claim 2] When the load is energized, the first semiconductor switching element is brought into conduction, and when the load is not energized, the second semiconductor switching element is brought into conduction to form a pseudo load having the same electric resistance as the load. It is a structure that energizes. Therefore, the output voltage of the rectifier circuit does not change even when the energization state of the load is switched.

The voltage monitoring unit monitors the voltage of the commercial power source based on the output voltage of the rectifier circuit connected to the secondary winding of the power transformer. Therefore, a secondary winding for commercial voltage monitoring and a rectifier circuit are not necessary, and it is not necessary to insulate the voltage monitoring unit from the primary side of the power transformer. Therefore, the voltage monitoring device can accurately monitor the voltage of the commercial power source at low cost.

[Claim 3] When the load is energized, a control signal is input to the control terminal to bring the semiconductor switch element into a conductive state, so that the pseudo load is not energized and the load is not energized. Since there is no input, the pseudo load is energized. Therefore, the output voltage of the rectifier circuit does not change even when the energization state of the load is switched.

The voltage monitoring unit monitors the voltage of the commercial power source based on the output voltage of the rectifier circuit connected to the secondary winding of the power transformer. Therefore, a secondary winding for commercial voltage monitoring and a rectifier circuit are not necessary, and it is not necessary to insulate the voltage monitoring unit from the primary side of the power transformer. Therefore, the voltage monitoring device can accurately monitor the voltage of the commercial power source at low cost.

[Claim 4] When the relay operation instructing section of the microcomputer determines that the relay is to be operated, an energization instruction signal is sent, the first transistor is turned on, and the relay is energized. If you decide not to activate, the connection point becomes high level,
In this configuration, the second transistor is turned on to energize the pseudo load having the same resistance value as the relay. Therefore, even if the operating state of the relay is switched, the output voltage of the rectifier circuit does not change.

The voltage monitoring unit monitors the voltage of the commercial power source based on the output voltage of the rectifier circuit connected to the secondary side of the power transformer. Therefore, a secondary winding for commercial voltage monitoring and a rectifier circuit are not necessary, and it is not necessary to insulate the voltage monitoring unit from the primary side of the power transformer. Therefore, the voltage monitoring device can accurately monitor the voltage of the commercial power source at low cost.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention (corresponding to claims 1, 2, and 4) will be described with reference to FIG. Commercial voltage monitor A
Is the power transformer 1 and the secondary winding 12 of the power transformer 1.
A rectifier circuit 2 connected to the rectifier circuit 2, a relay 3 and a digital transistor 4 connected to the output side of the rectifier circuit 2, a resistor 5 and a digital transistor 6 connected to the output side of the rectifier circuit 2, and a rectifier circuit 2 It is equipped with a voltage dividing circuit 7 for dividing the output voltage of 1 and a microcomputer 8 and is assembled in a hot air heater. Incidentally, 91 is a convection fan motor, and 92 is a motor energization control circuit.

The power transformer 1 is a commercial power source 10 (AC-
It has a primary winding 11 connected to 100V), a secondary winding 12 for a relay power supply, and another secondary winding {for 5V; not shown} for operating the microcomputer 8 and the like.

The rectifier circuit 2 comprises a silicon bridge diode 21 and a smoothing capacitor 22.
The silicon bridge diode 21 has an AC input terminal 21.
1, 212 are connected to the secondary winding 12, and the rectified output terminal 21
3, 214 is a plus terminal 22 of the smoothing capacitor 22.
1, connected to the minus terminal 222.

Relay 3 {in this embodiment, DC-24V,
The internal resistance 240 Ω} has a rectified output terminal 213 at one end 31.
The other end 32 is connected to one end 41 of the digital transistor 4 and the other end 642 of the resistor 64. Further, the louver motor 30 is connected to the commercial power source 10 via the normally open contact 33 of the relay 3. Reference numeral 36 is a flywheel diode.

The other end 42 of the digital transistor 4 is connected to the rectified output terminal 214, and the control terminal 43 is connected to the output port 821 of the microcomputer 8.
When the energization instruction signal 820 is sent from the output port 821, the digital transistor 4 is electrically connected between the one end 41 and the other end 42.

The resistor 5 has the same resistance value as the relay 3 (240Ω in this embodiment). The one end 51 is connected to the rectified output terminal 213, and the other end 52 is connected to the one end 61 of the digital transistor 6.

The other end 62 of the digital transistor 6 is connected to the rectified output terminal 214, and the control terminal 63 is connected to the resistor 64.
Is connected to one end 641 of the. In this digital transistor 6, the control terminal 63 becomes high level {when the energization instruction signal 820 is not sent from the output port 821}.
Then, the one end 61 and the other end 62 are electrically connected.

The voltage dividing circuit 7 is composed of resistors 71 and 72, divides the rectified voltage Es and sends it to the input port 811 of the microcomputer 8. The relationship among the voltage E of the commercial power source 10, the rectified voltage Es, and the divided voltage Eb is as follows in this embodiment.

E Es Eb 80V 19.2V 2.4V 90V 21.6V 2.7V 100V 24.0V 3V 110V 26.4V 3.3V

The microcomputer 8 includes a voltage monitoring unit 8
1, a relay operation instruction section 82, and a motor control section 83. The voltage monitoring unit 81 detects the voltage E of the commercial power supply 10 based on the following formula. E = Eb × (100/3)

When the louver operation instruction signal 801 is input to the microcomputer 8, the relay operation instruction unit 82 instructs the output port 821 to output the energization instruction signal 820.

The motor control section 83 has a convection fan motor 9
The output signal for rotating 1 at a predetermined rotation speed is corrected based on the voltage E of the commercial power supply 10 detected by the voltage monitoring unit 81, and an instruction to send the corrected control signal 830 is issued.

The motor energization control circuit 92 controls the control signal 8 sent from the output port 831 of the microcomputer 8.
Based on 30, the amount of electricity supplied to the convection fan motor 91 is feedforward controlled. The convection fan motor 91 is
Even if the voltage E of the commercial power supply 10 fluctuates, it rotates at a predetermined rotation speed, and the impeller pivotally attached to the convection fan motor 91 blows out warm air according to the rotation speed into the room.

Next, the advantages of the commercial voltage monitoring device A of this embodiment will be described. [A] When the louver operation instruction signal 801 for operating the louver motor 30 is not input to the microcomputer 8, the energization instruction signal 820 from the output port 821.
Is not instructed by the relay operation instructing section 82, the digital transistor 4 becomes non-conductive, the connection point m becomes a high level state, the digital transistor 6 becomes conductive, and a current flows through the resistor 5 having the same resistance value as the relay 3. Flowing.

Further, the louver operation instruction signal 801 for operating the louver motor 30 is sent to the microcomputer 8
, The relay operation instructing unit 82 instructs the output of the energization instruction signal 820 from the output port 821, the digital transistor 4 becomes conductive, the relay 3 operates (the louver motor 30 operates), and the connection point m becomes In the low level state, the digital transistor 6 becomes non-conductive, and no current flows through the resistor 5.

With the above configuration, the rectified voltage Es does not fluctuate due to the operation / non-operation of the relay 3 (operation / stop of the louver motor 30). Then, the microcomputer 8 causes the voltage monitoring unit 81 to detect an output signal for rotating the convection fan motor 91 at a predetermined rotation speed.
The motor control unit 83 makes a correction based on the voltage E of 0 and sends the control signal 830.

Therefore, regardless of whether the louver motor 30 is operated or not and the value of the voltage E of the commercial power source 10, the convection fan motor 91 rotates at a predetermined rotation speed, and hot air of a set air volume is blown into the room. Do not give distrust to the user.

[A] The voltage monitoring unit 81 monitors the voltage of the commercial power source 10 based on the divided voltage Eb obtained by dividing the rectified voltage Es obtained by rectifying the AC voltage generated in the secondary winding 12 of the power transformer 1. This is the configuration. Therefore, a secondary winding for commercial voltage monitoring and a rectifier circuit are not required, and the voltage monitoring unit 8
There is no need to insulate 1 from the primary side. Therefore, the commercial voltage monitoring device A can accurately monitor the voltage of the commercial power source 10 at low cost.

[C] Digital transistors 4 and 6 are used to switch between energization of the resistor 5 and energization of the relay 3. Therefore, the cost of parts is low, and switching can be performed at high speed, and malfunction of the voltage monitoring unit 81 at the time of switching can be prevented.

Next, a second embodiment of the present invention (claim 1,
2) will be described with reference to FIG. The commercial voltage monitoring device B includes a power transformer 1, a rectifier circuit 2 connected to the secondary winding 12 of the power transformer 1, a load 34 and a transistor 44 connected to the output side of the rectifier circuit 2, and a rectifier circuit. The pseudo load 53, the transistor 65, the voltage dividing circuit 7 for dividing the output voltage of the rectifier circuit 2, and the microcomputer 8 which are connected to the output side of 2 are provided in the microwave oven.

The load 34 is a light bulb (24V) for illuminating the inside of the refrigerator.
-48 W), one end 341 is connected to the rectified output terminal 20, and the other end 315 is the collector 443 of the transistor 44.
Connected to In the transistor 44, the base 441 is connected to the output port 821 via the resistor 442, and the emitter 444 is grounded.

The pseudo load 53 is a resistance of 12Ω, one end 531 is connected to the rectified output terminal 20, and the other end 532 is connected to the collector 651 of the transistor 65. In the transistor 65, the base 652 is connected to the connection point m2 via the resistor 654, and the emitter 653 is grounded.

The microcomputer 8 includes a voltage monitoring unit 8
0 and an energization instruction unit 84. The energization instruction unit 84 is
When the lighting instruction signal 802 (transmitted from the illumination lamp lighting switch) 802 is input to the microcomputer 8, the output port 821 is instructed to transmit the energization instruction signal 820.

The voltage monitoring unit 80 controls the voltage E of the commercial power source 10.
Is detected based on the following formula, and the detected voltage E is 80
When the voltage is less than V or 110 V or more for a predetermined time (for example, 1 second), an operation stop signal (not shown) is sent to instruct the operation stop. E = Eb × (100/3)

Next, the advantages of the commercial voltage monitoring apparatus B of this embodiment will be described. [D] The pseudo load 53 is not energized when the light bulb (load 34) is not lit, and the pseudo load 53 is not energized when it is lit. For this reason, since the rectified voltage Es does not change depending on whether the electric bulb is turned on or off, it is possible to accurately detect the presence or absence of a commercial voltage abnormality (when the voltage is less than 80 V or exceeds 110 V).

[E] The detected power supply voltage is less than 80 V or 11
If the voltage monitoring unit sends an operation stop signal to instruct the operation stop as soon as the voltage exceeds 0 V, the actual voltage E
Is relatively high (when the voltage is 110 V or less and is close to 110 V), the voltage monitoring unit may malfunction and the operation may be stopped. This is because the transistors 44 and 65 are turned on and off at the same time when the energization instruction signal 820 is sent, and the bulb (load 3
4) lights up, power consumption in the pseudo load 53 stops,
Since the resistance value is high at the beginning of lighting the light bulb, the voltage E
This is because s and Eb increase. However, since the commercial voltage monitoring device B has a configuration in which the voltage monitoring unit 80 sends an operation stop signal to instruct the operation stop when the detected power supply voltage is less than 80 V or continues to be 110 V or more for a predetermined time, the above-mentioned erroneous Operation can be prevented.

[F] The AC voltage generated in the secondary winding 12 of the power transformer 1 is rectified, and the voltage monitoring unit 80 causes the voltage E of the commercial power supply 10 to be detected based on the divided voltage Eb obtained by dividing the rectified voltage Es. Is configured to monitor. Therefore, since the secondary winding for lighting the electric bulb is used, a dedicated secondary winding for commercial voltage monitoring is not required and the voltage monitoring unit 80 does not need to be insulated from the primary side. Therefore, the commercial voltage monitoring device B
Can accurately monitor the voltage E of the commercial power supply 10 at low cost.

Next, a third embodiment of the present invention (corresponding to claim 3) will be described with reference to FIG. Commercial voltage monitoring device C
Is the power transformer 1 and the secondary winding 12 of the power transformer 1.
The rectifier circuit 2 connected to the rectifier circuit 2, the load 34 and the transistor 44 connected to the output side of the rectifier circuit 2, and the rectifier circuit 2
The pseudo load circuit 66, the voltage dividing circuit 7 that divides the output voltage of the rectifier circuit 2, and the microcomputer 8 that are connected to the output side of the, are provided in the microwave oven.

The pseudo load circuit 66 has a pseudo load 53 and a transistor 65 connected in series to the output side of the rectifier circuit 2. In the pseudo load circuit 66, when the control signal 841 is not input, the transistor 65 is turned on and the pseudo load 53 is energized. The commercial voltage monitoring device C of the present embodiment also exhibits the effects according to the above (D) to (F).

Next, a fourth embodiment of the present invention (corresponding to claim 1) will be described with reference to FIG. Commercial voltage monitoring device D
Is the power transformer 1 and the secondary winding 12 of the power transformer 1.
The load circuit 35 and the pseudo load circuit 54 connected to each other, the rectifier circuit 2 connected to the secondary winding 12, and the voltage monitoring circuit 9 for monitoring the voltage E of the commercial power supply 10 are provided and assembled to various devices. Has been.

The load circuit 35 comprises a freeze prevention switch 90 and an electric heater 351 connected in series, and when turned on, the electric heater 351 is connected to the secondary winding 12.
The pseudo load circuit 54 is configured by connecting an antifreezing switch 90 and a pseudo load 541 in series.
When 0 is off, the pseudo load 541 is connected to the secondary winding 12.

The voltage monitoring circuit 9 detects the voltage E of the commercial power source 10.
Is detected and the detected voltage E continues to be less than 80 V or 110 V or more for a predetermined time (for example, 5 seconds), the operation is stopped to ensure the safety of the equipment.

Next, the advantages of the commercial voltage monitoring device D of this embodiment will be described. [G] By the freeze prevention switch 90, the electric heater 351
When the electric heater 351 is not energized, the pseudo load 541 is energized, and when the electric heater 351 is energized, the pseudo load 541 is not energized. Therefore, the freeze prevention switch 9
Since the rectified voltage Es does not change even if 0 is switched to any direction, the commercial voltage abnormality {below 80 V or 110
If V is exceeded}, it can be detected.

[H] The detection power supply voltage is less than 80 V or 11
If the voltage monitoring circuit 9 is configured to stop the operation as soon as it exceeds 0 V, if the actual voltage E is relatively high {8
When the voltage is 0 V or higher and is close to 80 V}, the voltage monitoring circuit 9
May malfunction and stop operation. This is because when the antifreezing switch 90 is turned on from off, the secondary AC voltage decreases because the resistance value is low at the start of energization of the electric heater 351. However, the commercial voltage monitoring device D
The above malfunction can be prevented because the voltage monitoring circuit 9 is configured to stop the operation when the detected power supply voltage is lower than 80 V or continuously exceeds 110 V for a predetermined time or longer.

[0060]

[Brief description of drawings]

FIG. 1 is an electric circuit diagram of a voltage monitoring device according to a first embodiment of the present invention.

FIG. 2 is an electric circuit diagram of a voltage monitoring device according to a second embodiment of the present invention.

FIG. 3 is an electric circuit diagram of a voltage monitoring device according to a third embodiment of the present invention.

FIG. 4 is an electric circuit diagram of a voltage monitoring device according to a fourth embodiment of the present invention.

[Explanation of symbols]

1 Power Transformer 2 Rectifier Circuit 3 Relay (Load) 4 Digital Transistor (First Transistor) 6 Digital Transistor (Second Transistor) 8 Microcomputer (Controller) 9 Voltage Monitoring Circuit (Voltage Monitoring Means) 10 Commercial Power Supply 11 Primary Winding 12 Secondary Winding 34 Load 35 Load Circuit 43 Control Terminal 44 Transistor (First Semiconductor Switching Element) 53 Pseudo Load 54 Pseudo Load Circuit 63 Control Terminal 65 Transistor (Second Semiconductor Switching Element) 80 Voltage Monitoring Section (Voltage Monitoring Unit) 81 voltage monitor (voltage monitor) 82 relay operation instructor 84 energization instructor 801 louver operation instructing signal (signal) 820 energization instructing signal 841 control signal Es rectified voltage (output voltage) E voltage A, B, C, D commercial Voltage monitoring device m connection point m ₂ connection point

Claims (4)

[Claims] 1. A power transformer having a primary winding connected to a commercial power source, a rectifier circuit connected to the secondary winding of the power transformer, and a load circuit connected to the secondary winding side of the power transformer. A voltage monitoring unit that monitors the voltage of the commercial power source based on the output voltage of the rectifier circuit, and the same electrical resistance as that of the load circuit, which is connected to the secondary winding side of the power transformer, And a pseudo load circuit which is deactivated when the circuit is activated and activated when the load circuit is deactivated. 2. A power transformer having a primary winding connected to a commercial power source, a rectifier circuit connected to the secondary winding of the power transformer, a load and a first semiconductor connected in series to the output side of the rectifier circuit. A switch element, a pseudo load and a second semiconductor switch element connected in series to the output side of the rectifier circuit, a voltage monitoring unit that monitors the voltage of the commercial power source based on the output voltage of the rectifier circuit, and the load. And a controller having an energization instructing unit for instructing to send out an energization instruction signal to the first semiconductor switch element when energizing, wherein the electric resistance of the pseudo load is the same as the electric resistance of the load, A connection point between the load and the first semiconductor switching element,
A voltage monitoring device that is electrically connected to a control terminal of the second semiconductor switch element and is in a conductive state when the load is not energized. 3. A power transformer having a primary winding connected to a commercial power source, a rectifier circuit connected to the secondary winding of the power transformer, and a load and a semiconductor switch element connected in series to the output side of the rectifier circuit. And a pseudo load circuit having a pseudo load having the same electric resistance as that of the load and connected to the output side of the rectifier circuit, and a voltage monitoring unit that monitors the voltage of the commercial power source based on the output voltage of the rectifier circuit. , And a controller having an energization instructing unit for instructing to send a control signal to the control terminals of the semiconductor switch element and the pseudo load circuit when energizing the load, the pseudo load circuit is A voltage monitoring device for energizing the dummy load when no input is made. 4. A power transformer having a primary winding connected to a commercial power source, a rectifier circuit connected to the secondary winding of the power transformer, a relay and a first transistor serially connected to the output side of the rectifier circuit. A pseudo load and a second transistor connected in series to the output side of the rectifier circuit, a voltage monitoring unit that monitors the voltage of the commercial power source based on the output voltage of the rectifier circuit, and the voltage based on an input signal. And a microcomputer having a relay operation instructing section for instructing to send an energization instruction signal to the first transistor when determining whether or not to operate the relay, and the electric resistance of the pseudo load is the relay. Is the same as the electrical resistance of, the connection point between the relay and the first transistor, the control terminal of the second transistor is electrically connected, the second transistor Is a voltage monitoring device that becomes conductive when the relay is inactive.