JP2004166449A - Power supply device - Google Patents

Abstract

Disclosed is a power distribution unit having a magnetic material with a winding provided in the vicinity of a wiring through which an alternating current flows. In a power supply device that supplies power, the same power source supplies stable power to a power-supplied body even when the length of wiring and the number of power distribution units are different.
An AC current flowing through a wiring (18) is detected by a current detecting means (17), and the number of windings of a load adjusting means (19) is switched according to the detected magnitude of the AC current to connect the wiring to the wiring (18). The magnitude of the alternating current flowing through the wiring 18 is adjusted.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power supply device that includes a magnetic body provided with a winding near a wiring through which an alternating current flows, and supplies power to a power-supplied body by using a current that is electromagnetically induced to flow through the winding. It is about.
[0002]
[Prior art]
Conventionally, when using a power source such as a household power source or a battery to light a power-supplied object such as a light bulb or a fluorescent lamp, the light bulb or the like is directly connected to the wiring connected to the power source or the like, so that the light source or the like can be used. Power is supplied or a connector or socket is connected to the wiring, and power is supplied to a light bulb or the like through the connected connector or socket. For example, in an illumination device to be decorated on a Christmas tree, a plurality of sockets are provided in advance on the wiring, and power is supplied to the light bulb through this socket, but power is supplied through the socket as described above. Therefore, for example, if the user attempts to change the position or number of light bulbs, it is necessary to change the position or number of sockets from which power is to be extracted. It is not easy because it has to be added, and since a socket or the like has direct electrical contact with the wiring, an accident may occur due to an electrical factor such as a short circuit or a short circuit. In view of this, the present applicant has provided a power distribution means having a magnetic material provided with a winding in the vicinity of a wiring through which an alternating current flows, and utilizes a current that is electromagnetically induced and flows through the winding of the power distribution means. A power supply device for supplying power to a power-supplied body has been proposed.
[0003]
[Patent Document 1]
JP-A-8-305450
[Patent Document 2]
JP-A-10-215530
[Problems to be solved by the invention]
However, in the above-described power supply device, the length of the AC current wiring differs depending on the installation purpose and the installation environment of the power-supplied device, and the impedance of the wiring differs. In the case of using a power supply, an excessive AC current may flow in a power supply device having a relatively short wiring length, or a sufficient AC current may not flow in a power supply device having a relatively long wiring length. Therefore, in order to supply stable power to the power-supplied object in all power supply devices, it is necessary to adjust the voltage of the power supply according to the length of the wiring, and the size of the power supply device increases. Had occurred. Further, even when a plurality of power distribution means are provided on the wiring, the same problem as described above occurs because the impedance varies depending on the number. Furthermore, when detachable ones are used as a plurality of power distribution means, since the magnitude of the alternating current varies depending on the number of power distribution means in one power supply device, it is necessary to supply stable power to the power supply target. Becomes difficult.
[0006]
In view of the above-described circumstances, the present invention provides a power distribution unit having a magnetic material provided with a winding near a wiring through which an alternating current flows, and electromagnetically flows through the winding of the power distribution unit by electromagnetic induction. Provided is a power supply device that supplies electric power to a power-supplied object by using current, and can supply stable power to the power-supplied object with the same power supply even when the length of wiring and the number of power distribution units are different. It is intended to do so.
[0007]
[Means for Solving the Problems]
The power supply device of the present invention has a wiring through which an alternating current flows, and a magnetic body provided with a winding provided near the wiring so that the winding is close to the wiring, and according to the alternating current flowing through the winding. A current detecting means for detecting an alternating current flowing through the wiring, and at least one load, the power detecting apparatus comprising: at least one power distribution means for distributing the bidirectional current to the power receiving body; And a load adjusting means for adjusting the magnitude of the alternating current by connecting a load to the wiring according to the magnitude of the alternating current detected by the method.
[0008]
Here, the “alternating current” may be, for example, an output from a home power supply, or a conversion of a direct current output from a direct current power supply into an alternating current.
[0009]
In addition, the “wiring” means, for example, a copper wire or the like arranged to flow the alternating current. Alternatively, the copper wire or the like may be covered.
[0010]
Further, the expression "the winding is close to the wiring" means that the winding is located near the wiring without having direct electrical contact with the wiring. However, when the wiring is covered, this includes the case where the wiring is disposed in contact with the covering. Further, it is desirable that the winding be provided in a direction substantially the same as the wiring direction of the wiring.
[0011]
Further, the “bidirectional current” is a current electromagnetically induced in the winding by an alternating current flowing through a wiring, and means a current that switches in a positive or negative direction at a cycle corresponding to the alternating current.
[0012]
Further, the “power-supplied body” means, for example, a light bulb or a sensor, but does not necessarily need to be directly connected to and integrated with the “power distribution means”. For example, the power distribution means may be a socket or an outlet. Indirect connection means may be provided so that the power-supplied body receives power supply based on the bidirectional current via the connection means.
[0013]
The term "adjusting the magnitude of the AC current" means, for example, adjusting the magnitude of the AC current to be within a predetermined range, preferably to a predetermined current value. To do.
[0014]
Further, in the above-mentioned power supply device, the load adjusting means has a winding as a load, and the magnitude of the alternating current can be adjusted by switching and connecting the number of turns of the winding.
[0015]
Further, the load adjusting means may include a plurality of resistance elements connected in series as a load, and the magnitude of the alternating current may be adjusted by switching the number of the resistance elements and connecting them.
[0016]
In addition, the power distribution means is detachable from the wiring, and has wiring state detection means for detecting a state in which the power distribution means is not provided on the wiring based on the magnitude of the alternating current detected by the current detection means. It can be.
[0017]
Here, the term "removable with respect to the wiring" means that the power distribution means can be attached so that the magnetic substance is close to the wiring, and can be detached from the wiring.
[0018]
Further, "detecting a state in which the power distribution means is not provided on the wiring based on the magnitude of the alternating current detected by the current detecting means" means, for example, detecting the current value of the alternating current itself, By detecting that the value is equal to or greater than a predetermined threshold, the state where the power distribution means is not provided in the wiring may be detected, or the connection state of the load in the state where the power distribution means is not provided in the wiring May be stored in advance, and by detecting that the connection state of the load is the previously stored state, a state in which the power distribution means is not provided on the wiring may be detected. Note that the predetermined threshold value is a current value of an alternating current flowing through the wiring in a state where the wiring is not provided with the power distribution means, which is measured in advance by an experiment or the like.
[0019]
An AC power supply for outputting an AC current, and an AC power supply for intermittently supplying the AC current to the wiring while the wiring state detecting means detects that the power distribution means is not provided on the wiring. And AC power control means for controlling.
[0020]
In addition, the power distribution means is made detachable from the wiring, and a wiring detecting wire is provided on the magnetic material, and a voltage for detecting that a voltage generated in the wiring winding is equal to or less than a predetermined threshold value. It may have a detecting means.
[0021]
Further, while the AC power source that outputs the AC current and the voltage detection unit detects that the voltages of all the wiring detection windings of at least one power distribution unit are equal to or lower than a predetermined threshold, the AC current is applied to the wiring. AC power control means for controlling the AC power so as to flow intermittently.
[0022]
【The invention's effect】
According to the power supply device of the present invention, the magnitude of the alternating current is adjusted by detecting the alternating current flowing through the wiring and connecting at least one load to the wiring according to the detected magnitude of the alternating current. Therefore, even when the length of the wiring and the number of power distribution means are different, stable power can be supplied to the power-supplied body using the same power supply.
[0023]
Further, in the above-mentioned power supply device, the magnitude of the alternating current is adjusted by switching and connecting the number of windings of the winding in the load adjusting means, or by switching and connecting the number of resistance elements in the load adjusting means. When the magnitude of the alternating current is adjusted, the magnitude of the alternating current can be easily adjusted with a simple configuration.
[0024]
Further, when the power distribution means is detachable with respect to the wiring, and the state where the power distribution means is not provided in the wiring is detected based on the magnitude of the alternating current detected by the current detection means, For example, if the AC power supply is controlled so that the AC current is intermittently supplied to the wiring while it is detected that the power distribution means is not provided on the wiring, the AC current is uselessly supplied. Can be avoided.
[0025]
In addition, the power distribution means is made detachable with respect to the wiring, and a wiring detection winding is provided on the magnetic material so that a voltage generated in the wiring winding is detected to be equal to or less than a predetermined threshold. In such a case, for example, the AC power supply is controlled so that an AC current is intermittently supplied to the wiring while the voltages of all the wiring detection windings are detected to be equal to or lower than a predetermined threshold. By doing so, it is possible to avoid passing an alternating current unnecessarily. Further, a state in which the power distribution means is not provided on the wiring can be detected with a simple configuration.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a power supply device of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of an embodiment of a power supply device according to the present invention. FIG. 2 is a detailed circuit diagram of the control unit 16, the current detection unit 17, and the load adjustment unit 19 described later.
[0027]
The power supply apparatus includes a DC power supply 10 that outputs a DC current, an oscillation circuit 12 that is connected to the DC power supply 10, generates and outputs a signal of a predetermined frequency, and divides a signal output from the oscillation circuit 12 into a desired frequency. A signal generating circuit 14 for outputting a frequency-divided signal by dividing the frequency; a control means 16 for switching the frequency-divided signal output from the signal generating circuit 14 in the positive / negative direction and outputting the signal; and a wiring 18 through which an alternating current output from the control means 16 flows A power distribution means 20 provided near the wiring 18 and through which a bidirectional current electromagnetically induced by the alternating current flowing through the wiring 18 flows; a current detecting means 17 for detecting the magnitude of the alternating current flowing through the wiring 18; A load adjusting means 19 is provided for connecting a load in accordance with the magnitude of the alternating current detected by the detecting means 17 and controlling the magnitude of the alternating current.
[0028]
The oscillation circuit 12 generates a signal of several tens of kHz, and the signal generation circuit 14 divides the signal to generate and output a frequency-divided signal having a frequency of several hundred Hz to several tens kHz. is there.
[0029]
As shown in FIG. 1, the wiring 18 is connected to the control unit 16 and the load adjusting unit 19, and may be, for example, a single copper wire or a plurality of spirally integrated wires. It may be made of a copper wire. By passing an alternating current through this copper wire, a bidirectional current based on the alternating current can be passed through the power distribution means 20.
[0030]
As shown in FIG. 2, the current detecting means 17 is composed of a comparator. When the magnitude of the alternating current flowing through the wiring 18 is larger than a current value in a predetermined range, the UP signal is sent to the load adjusting means 19. And outputs a DOWN signal to the load adjusting means 19 when the magnitude of the alternating current is smaller than a current value in a predetermined range.
[0031]
The load adjusting means 19 includes a coil 25 provided with the windings 25a to 25d, a relay 26 for switching a connection state of the windings 25a to 25d of the coil 25 to the wiring 18, and an UP signal or DOWN output from the current detecting means 17. It has an up / down shift register 27 for switching the switches 26a to 26e of the relay 26 according to the signal.
[0032]
Details of the power distribution means 20 are shown in FIGS. FIG. 3 is a perspective view of the power distribution means 20, and FIG. 4 is a sectional view of the power distribution means 20 shown in FIG. As shown in FIG. 3, the power distribution means 20 includes a half-cylinder-shaped first magnetic body 22 and a half-cylinder-shaped second magnetic body 23 having windings 21 provided in the same direction as the wiring direction of the wiring 18. Have been. As shown in FIG. 4, the wiring 18 is provided in close contact with the inside of the cylinder of the second magnetic body 23, and the second magnetic body 23 is fixed to the fixing member 24.
[0033]
The fixing member 24 includes, for example, a top plate such as a desk or a table, a wall material, and the like. The second magnetic body 23 and the wiring 18 are not directly visible from the side where the first magnetic body 22 is provided. . A recess 24a is provided on the surface of the fixed member 24 on the side where the first magnetic body 22 is provided, as shown in FIG. 4, so that the first magnetic body 22 is provided at a position facing the second magnetic body 23. I have. In the present embodiment, the recess 24a is provided on the surface of the predetermined fixing member 24 as described above. However, the present invention is not limited to this, and the surface on the side where the first magnetic body 22 is provided is opposed to the second magnetic body 23. Alternatively, a square figure or the like indicating the position may be described. Further, the first magnetic body 22 and the second magnetic body 23 may be brought into direct contact without providing the fixing member 24.
[0034]
Next, the operation of the present power supply device will be described.
[0035]
First, the oscillation circuit 12 is driven by the DC power supply 10 to generate a signal of a predetermined frequency. The signal generated by the oscillation circuit 12 is input to a signal generation circuit 14, which divides the input signal to a desired frequency and outputs the frequency-divided signal to the control means 16. The control means 16 switches the input frequency-divided signal in the positive / negative direction and outputs it to the wiring 18 as an alternating current. As the waveform of the alternating current, for example, there is a waveform as shown in FIG. 5, and a signal of cycle t may be output for a desired power supply time T1. In this state, the first magnetic body 22 is not yet provided on the fixed member 24, and only the switch 26e is turned on in the relay 26 of the load adjusting means 19, and the other switches 26a to 26a are turned on. 26d is open. That is, the winding of the coil 25 of the load adjusting unit 18 is not connected to the wiring 18.
[0036]
The current value of the alternating current flowing through the wiring 18 in the above state is detected by the current detecting means 17. Then, as shown in FIG. 6, for example, when the current value of the current detected by the (arrow t1) the current detecting means 17 in the above state is higher than a predetermined threshold value I _1, the current detecting means 17 And outputs an UP signal to the up / down shift register 27 of the load adjusting unit 19. The threshold I ₁ is a value larger by a predetermined tolerance than a target value of the alternating current flowing through the wiring 28 I. When the UP signal is input to the up-down shift register 27, the up-down shift register 27 outputs a control signal to the relay 26 to turn on the switch 26d. The relay 26 turns on the switch 26d according to the control signal. When the switch 26d is turned on, the winding 25d of the coil 25 is connected to the wiring 18, whereby the impedance increases and the current value of the alternating current decreases (arrow t2). Then, the current value of the alternating current is detected by the current detecting means 17 again. Then, the detected current value, as shown in FIG. 6, if still greater than the threshold I ₁ (arrow t3), is output UP signal to the up-down shift register 27 from the current detecting means 17 again, The up / down shift register 27 outputs a control signal to the relay 26 to turn on the switch 26c. When the switch 26c is turned on, the winding 25c of the coil 25 is further connected to the wiring 18, whereby the impedance further increases and the current value of the alternating current further decreases. In the present embodiment, as shown in FIG. 6, the magnitude of the alternating current flowing through the wiring 18 when the switch 26c of the relay 25 is turned on is set to the target value I. There until less than the threshold I _1, and a switch control output and relay 26 of the control signal from the detection and the up-down shift register 27 of the current value by the current detecting means 17 as described above is repeated.
[0037]
Next, the first magnetic body 22 is installed in the concave portion 24 a of the fixing member 24, and the alternating current flowing through the wiring 18 passes through the hollow portion formed by the first magnetic body 22 and the second magnetic body 23 in the power distribution unit 20. I do. The passage of the alternating current causes the electromagnetically induced bidirectional current to flow through the winding 21 of the first magnetic body 22. Then, a bidirectional current having a waveform corresponding to the waveform of the alternating current flowing through the wiring 18 flows through the winding 21. By disposing the first magnetic body 22 as described above, the impedance increases and the current value of the alternating current decreases (arrow t4). The detected current value of the alternating current by the current detecting means 17, for example, as shown in FIG. 6, when the current value is lower than a predetermined threshold value I ₂ is the DOWN signal from the current detecting means 17 The output is input to the up / down shift register 27 of the load adjusting unit 19. The threshold I ₂ is a value smaller by a predetermined tolerance than a target value of the alternating current flowing through the wiring 28 I. When the DOWN signal is input to the up / down shift register 27, the up / down shift register 27 outputs a control signal to the relay 26 to open the switch 26c. The relay 26 opens the switch 26c according to the control signal. When the switch 26c is opened, the winding 25c of the coil 25 is disconnected from the wiring 18, thereby reducing the impedance and increasing the magnitude of the alternating current (arrow t5). Then, the current value of the alternating current is detected by the current detecting means 17 again. In the present embodiment, as shown in FIG. 6, the magnitude of the alternating current flowing through the wiring 18 when the switch 26c of the relay 26 is opened is set to the target value I. to a size larger than the threshold I _2, and a switch control output and relay 26 of the control signal from the detection and the up-down shift register 27 of the current value by the current detecting means 17 as described above is repeated.
[0038]
In addition, the power supply voltage value of the DC power supply 10 is a value of the AC current flowing through the wiring 18 in a state where the windings 25 a to 25 d of the coil 25 are all connected to the expected shortest wiring 18 and the power distribution unit 20 is not installed. as the size becomes I ₂ or I ₁ or less, and winding 25a~25d are all cut from the longest wiring 18 is assumed, the magnitude of the alternating current in a state in which the power distribution unit 20 is installed is I ₂ it is necessary to set to be equal to or greater than I ₁ below. Furthermore, when a plurality of power distribution means 20 are installed on the wiring 18, the windings 25 a to 25 d are all cut from the assumed longest wiring 18, and the magnitude of the AC current is increased in a state where all the power distribution means 20 are installed. Saga needs to be set such that the I ₂ or I ₁ or less.
[0039]
According to the power supply device of the present invention, the magnitude of the alternating current is detected by detecting the alternating current flowing through the wiring 18 and connecting the windings 25a to 25d to the wiring 18 according to the detected magnitude of the alternating current. Since the adjustment is performed, even when the length of the wiring 18 or the number of the power distribution means 20 is different, stable power can be supplied to the power-supplied body by the same power supply.
[0040]
In the above embodiment, the connection state of the switches 26a to 26e of the relay 26 in the load adjustment unit 19 when the first magnetic body 22 of the power distribution unit 20 is not installed is stored in the storage unit 28 as shown in FIG. While the switch is stored and the connection state of the switches 26a to 26e of the relay 26 is the state stored in the storage unit 28, the control unit 16 intermittently outputs an alternating current of a predetermined cycle T2 as shown in FIG. You may do so. Further, while the connection state of the switches 26 a to 26 e of the relay 26 is the state stored in the storage unit 28, the control unit 16 may stop outputting the alternating current to the wiring 18.
[0041]
Further, instead of controlling the output of the alternating current by storing the connection state of the switch of the relay 26 in the storage unit 28 as described above, as shown in FIG. 9 and FIG. (2) A wiring detecting coil 29 is provided on the magnetic body 23, and voltage detecting means 30 for detecting that a voltage generated in the wiring detecting coil 29 has become equal to or less than a predetermined threshold value is provided. Assuming that the first magnetic body 22 is not installed while the applied voltage is equal to or lower than the predetermined threshold, an alternating current flowing through the wiring 18 is output intermittently at a predetermined cycle T2, May be stopped. Specifically, before the first magnetic body 22 is installed, the voltage waveform of the wiring detection coil 29 has a small amplitude and a positive amplitude of a predetermined threshold V1 as shown in FIG. Less than. At this time, the voltage detection means 30 detects that the voltage value of the wiring detection coil 29 is equal to or less than the threshold value V1, and outputs a detection signal to the control means 16. In response to this detection signal, the control means 16 intermittently outputs an alternating current to the wiring 18 at a predetermined cycle T2 as shown in FIG. When the first magnetic body 22 is installed, the amplitude of the voltage waveform generated in the wiring detection coil 29 increases (arrow s1), and becomes larger than a predetermined threshold V1. Then, the voltage detecting means 30 detects that the voltage value of the wiring detecting coil 29 has become larger than the threshold value V1, and outputs a detection signal to the control means 16, and in accordance with the detection signal, the control means 16 Continuously output an alternating current. A bidirectional current flows through the winding 21 of the power distribution means 20 according to the output of the continuous alternating current. Then, when the first magnetic body 22 is removed from the fixed member 24 (arrow s2), the amplitude of the voltage generated in the wiring detection coil 29 becomes smaller again, and becomes smaller than the threshold value V1. Then, this is detected by the voltage detecting means 30, and the voltage detecting means 30 outputs this detection signal to the control means 16. The control means 16 intermittently outputs an alternating current to the wiring 18 again in the cycle T2 in response to the detection signal. FIG. 12 shows a circuit diagram of the voltage detection means 30 and the control means 16 when, for example, two power distribution means 20 having wiring detection coils 29 are provided on the wiring 18. The voltage detection means 30 is configured to output a detection signal to the control means 16 when the magnitude of the voltage generated in the wiring detection coil 29 of at least one of the two power distribution means 20 is equal to or less than a predetermined threshold. The control means 16 is configured to output an alternating current intermittently to the wiring 18 according to the detection signal.
[0042]
Further, in the above embodiment, the bidirectional current flowing through the winding 21 of the first magnetic body 22 is stabilized by a constant voltage circuit 31 as shown in FIG. .
[0043]
Further, in the above embodiment, the magnitude of the alternating current flowing through the wiring 18 is controlled by changing the windings 25a to 25d of the coil 25 connected to the wiring 18, but the present invention is not limited to this. Alternatively, a plurality of resistance elements may be provided instead of the windings 25a to 25d, and the magnitude of the alternating current may be controlled by changing the number of resistance elements connected to the wiring 18.
[0044]
In the above embodiment, a fixing means for fixing the first magnetic body 22 and the second magnetic body 23 so that the first magnetic body 22 and the second magnetic body 23 sandwich the wiring 18 can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an embodiment of a power supply device according to the present invention; FIG. 2 is a circuit diagram of a control unit, a current detection unit, and a load adjustment unit in the power supply device shown in FIG. 1; FIG. 4 is a cross-sectional view of the power distribution means shown in FIG. 3; FIG. 5 is a diagram showing an example of a current waveform of an AC current flowing through the wiring; FIG. FIG. 7 is a diagram for explaining the relationship with the operation of the adjusting means. FIG. 7 is a schematic configuration diagram of another embodiment of the power supply device of the present invention. FIG. 8 shows a current waveform when an AC current is intermittently applied to wiring. FIG. 9 is a schematic configuration diagram of another embodiment of the power supply device of the present invention. FIG. 10 is a detailed view of a power distribution unit in the power supply device shown in FIG. 9. FIG. 11 explains the operation of the power supply device shown in FIG. FIG. 12 is a diagram illustrating the power supply in the power supply device shown in FIG. 9; Circuit diagram of the detection means and control means [13] Figure [EXPLANATION OF SYMBOLS] showing a circuit for outputting a power supply voltage bidirectional current flowing in the power distribution unit to an external device
REFERENCE SIGNS LIST 10 DC power supply 12 oscillation circuit 14 signal generation circuit 16 control means 17 current detection means 18 wiring 19 load adjustment means 20 power distribution means 21 winding 22 first magnetic body 23 second magnetic body 24 fixing member 25 coil 26 relay 27 up / down shift Register 28 storage means 29 wiring detection coil 30 voltage detection means 31 constant voltage circuit

Claims (7)

A wiring through which an alternating current flows, and a magnetic body provided with a winding provided near the wiring so that the winding is close to the wiring, and a bidirectional current corresponding to the alternating current flowing through the winding And at least one power distribution means for distributing power to the power-supplied body,
Current detection means for detecting an alternating current flowing through the wiring,
Load adjusting means for adjusting the magnitude of the alternating current by connecting the load to the wiring in accordance with the magnitude of the alternating current detected by the current detecting means. A power supply device, comprising: The load adjusting means has a winding as the load,
2. The power supply device according to claim 1, wherein the magnitude of the alternating current is adjusted by switching and connecting the number of turns of the winding. The load adjusting unit has a plurality of resistance elements connected in series as the load,
2. The power supply device according to claim 1, wherein the magnitude of the alternating current is adjusted by switching and connecting the number of the resistance elements. The power distribution means is detachable from the wiring,
4. The apparatus according to claim 1, further comprising a wiring state detecting unit configured to detect a state in which the power distribution unit is not provided on the wiring based on a magnitude of the alternating current detected by the current detecting unit. A power supply device according to the item. An AC power supply that outputs the AC current;
AC power supply control means for controlling the AC power supply so as to intermittently supply an AC current to the wiring while the wiring state detecting means detects that the wiring is not provided with the power distribution means. The power supply device according to claim 4, comprising: The power distribution means is detachable from the wiring, and the magnetic body is provided with a wiring detection winding,
4. The power supply device according to claim 1, further comprising a voltage detection unit configured to detect that a magnitude of a voltage generated in the wiring winding is equal to or smaller than a predetermined threshold. 5. An AC power supply that outputs the AC current;
While the voltage detecting means detects that the magnitude of the voltage of all of the wiring detection windings of the at least one power distribution means is equal to or less than the threshold value, an alternating current may be intermittently supplied to the wiring. 7. The power supply device according to claim 6, further comprising an AC power supply control unit for controlling the AC power supply.

Images