JP3487487B2 - Power switching circuit - Google Patents
Power switching circuitInfo
- Publication number
- JP3487487B2 JP3487487B2 JP00317097A JP317097A JP3487487B2 JP 3487487 B2 JP3487487 B2 JP 3487487B2 JP 00317097 A JP00317097 A JP 00317097A JP 317097 A JP317097 A JP 317097A JP 3487487 B2 JP3487487 B2 JP 3487487B2
- Authority
- JP
- Japan
- Prior art keywords
- power supply
- contact
- transformer
- circuit
- winding
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Description
【発明の詳細な説明】
【０００１】
【発明の属する技術分野】本発明は、電気機器のバック
アップ用に２系統の電源を備えた場合に、その電源の切
替をするための電源切替回路に関する。
【０００２】
【従来の技術】従来の電源切替回路として、図３に示す
ものがある。これは互いに異なる商用電源Ａ、Ｂを備
え、それぞれの一方の出力線を互いに接続して共通線と
し、他方の出力線をリレー接点を介し切替可能にして、
それぞれを変圧器Ｔｒの一次側に接続したものである。
これらの接点は、開閉動作時にアークが発生して開閉タ
イミングが遅れることがあり、その場合は電源Ａと電源
Ｂが短絡される。しかも、短絡したときの両電源の位相
が一致すると、過大な電流が流れることになる。そのた
め従来の電源切替回路では、接点容量の大きい電磁接触
器を用いている。また、電磁接触器の操作用コイルＭＣ
は、一方の電源の出力に並列に接続される。
【０００３】図示例では電源Ａに操作用コイルＭＣを接
続し、それにより駆動されるａ接点を電源Ａ側に、ｂ接
点を電源Ｂ側にそれぞれ接続することにより、電源Ａに
より操作用コイルＭＣが通電されている間は、ａ接点が
閉じてｂ接点が開き、電源Ａが変圧器Ｔｒに接続され
る。この状態から電源Ａがダウンすると、操作用コイル
ＭＣの励磁がなくなり、ａ接点およびｂ接点がともに復
帰して、電源Ｂが変圧器Ｔｒに接続される。また、電源
Ａが復旧すると、操作用コイルＭＣが再び励磁されて、
ａ接点およびｂ接点が作動し、元のように電源Ａが変圧
器Ｔｒに接続される。すなわちこの電源切替回路では、
電源Ａを優先して変圧器Ｔｒに接続するように構成され
ている。
【０００４】また、他の従来例として、図４に示すもの
がある。これは図３の電磁接触器の代わりに、リレーと
タイマーを用いたことにより、ａ接点の動作タイミング
を調整可能にしたものである。すなわち、電源Ａがダウ
ンして復旧する際に、リレーによりｂ接点が開かれると
アークが発生しｂ接点の開のタイミングが遅れる。その
ため、その遅れ分を予めタイマにセットしておくことに
より、ａ接点の閉じるタイミングを遅らせて、ａ接点お
よびｂ接点がともに閉じられる瞬間がないようにしたも
のである。なお、この従来例でタイマの代わりにリレー
を複数個組み合わせて、ｂ接点の動作タイミングを遅ら
せる構成とする場合もあった。
【０００５】
【発明が解決しようとする課題】上述した従来の電源切
替回路は、前者の場合、電磁接触器を用いるため全体の
容積が大きくなるとともにコストアップになるという不
都合があった。また、後者の場合は、電磁接触器を用い
ないので、容積等が増大することはないものの、タイマ
の設定が面倒である。すなわち、アークの発生には再現
性が乏しいため、短絡を確実に防ごうとするとタイマ設
定時間を長くしなければならず、その場合は、両電源と
も変圧器Ｔｒに接続されない期間が増大することにな
り、本来の電源をバックアップする目的からはずれてし
まう。そのため、タイマの設定時間にも上限があり、最
小限の短絡期間の発生はやむをえなかった。具体的に
は、２つの電源が短絡された場合に発生する電流は１０
０Ａに達することもあり、そのための対策が必要であっ
た。そこで、接点切替時のタイミング不良により２つの
電源が短絡されても大電流の流れることのない電源切替
回路の開発が望まれていた。
【０００６】
【課題を解決するための手段】そこで上記課題を解決す
るために、本発明は、変圧器の一次側巻線と互いに異な
る２つの電源の出力端との間に接続され、一方の電源に
より操作コイルが励磁されるａ接点とｂ接点とを有し、
そのａ接点を一方の電源の出力端と変圧器の一次側巻線
との間に接続し、そのｂ接点を他方の電源の出力端と変
圧器の一次側巻線との間に接続した電源切替回路におい
て、変圧器の一次側巻線を、一方の巻線回路と他方の巻
線回路とを互いに共通接続する共通線を介して分割され
た２回路とし、一方の巻線回路と一方の電源とを前記ａ
接点を介して接続するとともに、他方の巻線回路と他方
の電源とを前記ｂ接点を介して接続する。それにより、
接点切替時に、２つの電源がとともに変圧器に接続され
る期間が発生しても、変圧器の一次側巻線は互いに別回
路となり、その分、インピーダンスが増大して電流の増
大が抑制される。
【０００７】
【発明の実施の形態】本発明の実施形態を図１に示す。
この実施形態では、電源が接続される変圧器Ｔｒの一次
側巻線を巻線ＮＡと巻線ＮＢとに２分割し、それぞれを
１００Ｖの商用電源Ａと電源Ｂに接続する。すなわち、
電源Ａ，Ｂと巻線ＮＡ，ＮＢとを接続するそれぞれ一方
の配線を互いに接続して共通にし、電源Ａと巻線ＮＡの
他方の配線上にリレー接点ａを接続し、電源Ｂと巻線Ｎ
Ｂの他方の配線上にリレー接点ｂを接続する。また、こ
れら接点ａ，ｂの操作用コイルＲｙをともに電源Ａに接
続したものである。
【０００８】ここで、変圧器Ｔｒの鉄心断面積を適当な
値に設定し、一次側の巻線ＮＡを１００、巻線ＮＢを１
００、二次側の巻線を２４とした巻数比で設計すると、
電源Ａ，Ｂいずれの場合も一次側の電圧が１００Ｖであ
れば二次側の電圧は２４Ｖに変圧されて負荷に供給され
る。この実施形態では、変圧器Ｔｒ単体が、従来の変圧
器に比べて、見かけ上２００Ｖ／２４Ｖ変圧比相当とな
り一次巻線は２倍の巻数になるものの、もともと一次巻
線は二次巻線に対し断面積の小さい電線を使用している
ので、変圧器Ｔｒの容積は若千の増加ですむ。
【０００９】次に、この実施形態の動作について説明す
る。図１において、電源Ａと電源Ｂとから同時に電圧が
印加された場合、両接点の操作コイルＲｙが電源Ａによ
り励磁され、ａ接点は閉じられ、ｂ接点は開かれる。そ
の結果、電源Ａが選択されて変圧器Ｔｒの巻線ＮＡが通
電状態となる。また、電源Ｂのみから電圧が印加された
場合は、操作コイルＲｙが励磁されないため、ａ接点は
開かれた状態に、ｂ接点は閉じられた状態にそれぞれ復
帰する。その結果、電源Ｂが選択されて変圧器Ｔｒの巻
線ＮＢが通電状態となる
【００１０】次にこの状態から電源Ａの電圧が復帰する
と、操作コイルＲｙが励磁されて、ａ接点、ｂ接点が作
動して電源Ａから巻線ＮＡへ通電されると同時に、電源
Ｂから巻線ＮＢへの通電が断たれる。すなわち、この回
路では、電源Ａおよび巻線ＮＡが優先される。ここで、
電源Ａにより操作コイルＲｙが励磁されて、ａ接点が閉
じ、ｂ接点が開かれる場合について考えてみると、ｂ接
点は開かれた瞬間にアークを発生し、わずかの期間では
あるが引き続き導通状態が保たれる。同時にその間もａ
接点は閉じられているため、ａ接点、ｂ接点がともに閉
じられて、電源Ａと電源Ｂが短絡状態となる。しかしな
がら、この実施形態では、後述するように、電源Ａと電
源Ｂが短絡されても、それによる電流増大を最小限にす
ることができる。
【００１１】図２（ａ）は電源Ａと変圧器Ｔｒの一次巻
線ＮＡとで形成される閉回路を、図２（ｂ）は電源Ｂと
変圧器Ｔｒの一次巻線ＮＢとで形成される開回路を、そ
れぞれ等価回路的に模擬した図である。図において、電
源Ａと電源ＢのインピーダンスをそれぞれＺＡ，ＺＢ、
変圧器Ｔｒの一次側の巻線ＮＡと巻線ＮＢの巻線インピ
ーダンスをそれぞれＺＴＡ，ＺＴＢ、変圧器Ｔｒの二次
側巻線インピーダンスをＺＴ（一次換算）、変圧器Ｔｒ
の励磁インピーダンスをＺｏ（一次換算）、負荷インピ
ーダンスをＺｂ（一次換算）とする。
【００１２】それにより、両閉回路がａ接点とｂ接点間
でアーク短絡した瞬間の電流は、電気回路論の重ね合わ
せの理により、各閉回路ごとの電圧とインピーダンスと
により流れる電流の総和となる。また、実施形態で対象
にしている回路は、変圧器二次巻線インピーダンスと変
圧器励磁インピーダンス及びこの種の負荷のインピーダ
ンスの値が小さいので、それらを無視することができ
る。その結果、短絡電流は、電源Ａと電源Ｂ間で、主に
変圧器Ｔｒの一次巻線ＮＡと一次巻線ＮＢとで形成され
る直列回路を流れ、その近似値は、次式により求められ
る。
【００１３】
【数１】短絡電流＝（電源Ａ電圧十電源Ｂ電圧）／（Ｚ
Ａ＋ＺＢ＋ＺＴＡ＋ＺＴＢ）
【００１４】ここで、電源Ａと電源Ｂの電圧は１００Ｖ
であり、通常この種の変圧器の一次巻線インピーダンス
は５Ω程度であり、また、電源インピーダンスも十分小
さい値なので無視すると、最大短絡電流は、次式の値と
なり、大幅に低減できる。
【００１５】
【数２】短絡電流＝２００Ｖ／（５Ω＋５Ω）＝２０Ａ
【００１６】なお、短絡時に一瞬ではあるが、変庄器Ｔ
ｒの一次側の巻線全体に最高で２００Ｖが印加される
が、一次／二次総巻数比が２００Ｖ／２４Ｖ相当の変圧
比に設定してあり、鉄心飽和による回路の異常現象も心
配無く、変圧器Ｔｒの二次側に接続されている負荷に対
しても著しい電圧変動がなくなる。また、接点切替時
の、短絡時間も一瞬なので、変圧器Ｔｒの一次巻線に対
し、通電容量を増すためとくに断面積の大きい電線を使
用する必要もない。こうして、短絡電流が一瞬流れた後
に、ｂ接点が完全に開放しａ接点が接触して電源Ａに切
り替わり、変庄器Ｔｒの巻線ＮＡへ入力された電力は１
００Ｖ／２４Ｖに変圧されて負荷に供給される。
【００１７】このようにして、上述した実施形態では、
電源Ａと電源Ｂ間で短絡が発生しても、短絡電流が変圧
器巻線インピーダンスにより抑制されるため、小容量の
ＡＣリレーの使用が可能となる。また、本発明では、変
圧器Ｔｒの容積は若千増加するものの、回路全体では、
従来例のように電磁接触器や複数のリレーを組合わせる
ことがなくなり、小容量のリレー１個の使用ですみ、電
源切替回路のコストダウン及び回路の小型化が可能とな
る。なお、実施形態では２系統の電源を切り替えるため
片切りの切替回路を用いたが、両切りの切替回路の場合
も同様に適用可能である。
【００１８】
【発明の効果】以上述べたように本発明によれば、２つ
の電源が接続される変圧器の一次側巻線を２分割して電
源と巻線をそれぞれ対応させて接続したことにより、接
点切替時に、２つの電源がとともに変圧器に接続される
期間が発生しても、変圧器の一次側巻線が互いに別回路
となり、その分、インピーダンスが増大して電流の増大
が抑制される。その結果、従来用いていた電磁接触器、
タイマやリレーからなる遅延回路が不要となり、その
分、小型化とコストダウンが可能になる。Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a power supply switching circuit for switching a power supply when two power supplies are provided for backing up electric equipment. 2. Description of the Related Art FIG. 3 shows a conventional power supply switching circuit. This is provided with different commercial power supplies A and B, one output line of each is connected to each other to form a common line, and the other output line is switchable via a relay contact,
Each is connected to the primary side of the transformer Tr.
In these contacts, an arc is generated at the time of opening / closing operation, so that the opening / closing timing may be delayed. In addition, if the phases of the two power supplies coincide with each other when a short circuit occurs, an excessive current will flow. Therefore, in a conventional power supply switching circuit, an electromagnetic contactor having a large contact capacity is used. Also, the operation coil MC of the electromagnetic contactor
Are connected in parallel to the output of one power supply. In the illustrated example, an operating coil MC is connected to a power source A, and an a-contact driven thereby is connected to the power source A side and a b-contact is connected to the power source B side. Is energized, the contact a is closed and the contact b is opened, and the power supply A is connected to the transformer Tr. When the power supply A goes down from this state, the excitation of the operation coil MC is stopped, the contact a and the contact b are both restored, and the power supply B is connected to the transformer Tr. When the power supply A is restored, the operation coil MC is excited again,
The a-contact and the b-contact operate, and the power source A is connected to the transformer Tr as before. That is, in this power supply switching circuit,
The power supply A is configured to be connected to the transformer Tr with priority. FIG. 4 shows another conventional example. This uses a relay and a timer instead of the electromagnetic contactor shown in FIG. 3 so that the operation timing of the a contact can be adjusted. That is, when the power supply A goes down and is restored, if the relay opens the contact b, an arc is generated and the opening timing of the contact b is delayed. Therefore, by setting the delay in a timer in advance, the closing timing of the contact a is delayed so that there is no moment when both the contact a and the contact b are closed. In this conventional example, a plurality of relays may be combined in place of the timer to delay the operation timing of the contact b. In the former conventional power supply switching circuit, in the former case, the use of an electromagnetic contactor has the disadvantage of increasing the overall volume and increasing the cost. In the latter case, since the electromagnetic contactor is not used, the volume and the like do not increase, but the setting of the timer is troublesome. That is, since reproducibility of the occurrence of arc is poor, the timer setting time must be extended in order to reliably prevent a short circuit, in which case the period during which neither power supply is connected to the transformer Tr increases. , Which deviates from the purpose of backing up the original power supply. Therefore, there is an upper limit to the set time of the timer, and the occurrence of the minimum short-circuit period has been unavoidable. Specifically, the current generated when two power supplies are short-circuited is 10
In some cases, it could reach 0A, so measures were needed. Therefore, it has been desired to develop a power supply switching circuit in which a large current does not flow even when two power supplies are short-circuited due to a timing failure at the time of contact switching. [0006] In order to solve the So the object, according to an aspect of the present invention is connected between the primary winding and two different output terminals of the power supply transformer, whereas A contact and a b contact at which the operation coil is excited by the power supply of
A power supply having its a contact connected between the output terminal of one power supply and the primary winding of the transformer and its b contact connected between the output terminal of the other power supply and the primary winding of the transformer In the switching circuit, the primary winding of the transformer is connected to one winding circuit and the other winding.
It is split via a common line commonly connecting the line circuit from each other
And 2 circuit, the a and one power one winding circuit a has
The connection is made via a contact, and the other winding circuit and the other power supply are connected via the contact b. Thereby,
Even when a period in which the two power supplies are connected to the transformer is generated at the time of the contact switching, the primary windings of the transformer are separate circuits from each other, and the impedance is accordingly increased and the increase in the current is suppressed. . FIG. 1 shows an embodiment of the present invention.
In this embodiment, the primary winding of the transformer Tr to which the power is connected is divided into two windings NA and NB, each of which is connected to a commercial power supply A and a power supply B of 100V. That is,
One of the wirings connecting the power supplies A and B and the windings NA and NB is connected to each other to make them common, the relay contact a is connected on the other wiring of the power supply A and the winding NA, and the power supply B and the windings are connected. N
A relay contact b is connected to the other wiring of B. The operating coil Ry of these contacts a and b is both connected to the power supply A. Here, the core cross-sectional area of the transformer Tr is set to an appropriate value, the primary side winding NA is set to 100, and the winding NB is set to 1
00, when the secondary side winding is designed with a turns ratio of 24,
In both power supplies A and B, if the voltage on the primary side is 100 V, the voltage on the secondary side is transformed to 24 V and supplied to the load. In this embodiment, the transformer Tr alone has an apparent 200 V / 24 V transformation ratio equivalent to the conventional transformer, and the primary winding has twice the number of turns, but the primary winding is originally a secondary winding. On the other hand, since an electric wire having a small cross-sectional area is used, the volume of the transformer Tr can be increased by a small amount. Next, the operation of this embodiment will be described. In FIG. 1, when a voltage is simultaneously applied from the power supply A and the power supply B, the operation coil Ry of both contacts is excited by the power supply A, the contact a is closed, and the contact b is opened. As a result, the power supply A is selected, and the winding NA of the transformer Tr is turned on. When a voltage is applied only from the power supply B, the operation coil Ry is not excited, so that the contact a returns to an open state and the contact b returns to a closed state. As a result, the power source B is selected and the winding NB of the transformer Tr is energized. [0010] When the voltage of the power source A is restored from this state, the operation coil Ry is excited, and the contact a and contact b Is activated to supply electricity from the power supply A to the winding NA, and at the same time, supply of electricity from the power supply B to the winding NB is cut off. That is, in this circuit, the power supply A and the winding NA have priority. here,
Consider the case where the operating coil Ry is excited by the power supply A, the contact a is closed, and the contact b is opened. Is kept. At the same time
Since the contacts are closed, the contacts a and b are both closed, and the power supply A and the power supply B are short-circuited. However, in this embodiment, as will be described later, even if the power supply A and the power supply B are short-circuited, the current increase due to the short-circuit can be minimized. FIG. 2A shows a closed circuit formed by the power supply A and the primary winding NA of the transformer Tr, and FIG. 2B shows a closed circuit formed by the power supply B and the primary winding NB of the transformer Tr. FIG. 3 is a diagram simulating each open circuit as an equivalent circuit. In the figure, the impedances of power supply A and power supply B are ZA, ZB,
The winding impedance of the primary winding NA and the winding NB of the transformer Tr is ZTA and ZTB, respectively, the secondary winding impedance of the transformer Tr is ZT (primary conversion), and the transformer Tr is
, The excitation impedance is Zo (primary conversion), and the load impedance is Zb (primary conversion). Accordingly, the current at the moment when the two closed circuits arc short-circuit between the a-contact and the b-contact is determined by the sum of the currents flowing by the voltage and impedance of each closed circuit, based on the superposition of electric circuit theory. Become. In addition, the circuit targeted in the embodiment can ignore the transformer secondary winding impedance, the transformer excitation impedance, and the impedance of this type of load because these values are small. As a result, the short-circuit current flows between the power supply A and the power supply B through a series circuit mainly formed by the primary winding NA and the primary winding NB of the transformer Tr, and the approximate value is obtained by the following equation. . ## EQU1 ## Short-circuit current = (voltage of power supply A / voltage of power supply B) / (Z
A + ZB + ZTA + ZTB) Here, the voltage of the power supply A and the power supply B is 100 V
Normally, the primary winding impedance of this type of transformer is about 5Ω, and the power supply impedance is a sufficiently small value. If ignored, the maximum short-circuit current becomes the value of the following equation, which can be greatly reduced. [Equation 2] Short-circuit current = 200 V / (5Ω + 5Ω) = 20 A
200V is applied to the entire winding on the primary side of r, but the primary / secondary total turns ratio is set to a transformation ratio equivalent to 200V / 24V, and there is no fear of abnormal circuit phenomena due to core saturation. There is no significant voltage fluctuation even for the load connected to the secondary side of the transformer Tr. In addition, since the short-circuit time at the time of contact switching is also instantaneous, it is not necessary to use a wire having a particularly large cross-sectional area for the primary winding of the transformer Tr to increase the current carrying capacity. In this way, after the short-circuit current flows for a moment, the contact b is completely opened and the contact a contacts to switch to the power source A, and the power input to the winding NA of the transformer Tr is 1
It is transformed to 00V / 24V and supplied to the load. Thus, in the above-described embodiment,
Even if a short circuit occurs between the power supply A and the power supply B, the short-circuit current is suppressed by the transformer winding impedance, so that a small-capacity AC relay can be used. Further, in the present invention, although the volume of the transformer Tr increases by a small amount,
It is not necessary to combine an electromagnetic contactor and a plurality of relays as in the conventional example, and only one small-capacity relay is used, so that the cost of the power supply switching circuit and the size of the circuit can be reduced. In the embodiment, a one-sided switching circuit is used to switch between two power sources. However, a two-sided switching circuit is similarly applicable. As described above, according to the present invention, the primary winding of the transformer to which the two power supplies are connected is divided into two parts, and the power supplies and the windings are connected correspondingly. Therefore, even if a period occurs when the two power supplies are connected to the transformer together with the contact at the time of contact switching, the primary windings of the transformer become separate circuits from each other, and accordingly the impedance increases and the increase in current is suppressed. Is done. As a result, the conventional electromagnetic contactor,
The need for a delay circuit including a timer and a relay is eliminated, and the size and cost can be reduced accordingly.
【図面の簡単な説明】 【図１】本発明の実施形態を示す図である。 【図２】図１の回路構成を示すブロック図である。 【図３】従来例を示す図である。 【図４】従来例を示す図である。 【符号の説明】 Ａ，Ｂ 電源 ａ，ｂ 接点 ＮＡ，ＮＢ 一次側巻線 Ｒｙ 操作用コイル Ｔｒ 変圧器[Brief description of the drawings] FIG. 1 is a diagram showing an embodiment of the present invention. FIG. 2 is a block diagram showing a circuit configuration of FIG. 1; FIG. 3 is a diagram showing a conventional example. FIG. 4 is a diagram showing a conventional example. [Explanation of symbols] A, B power supply a, b contact NA, NB Primary winding Ry operation coil Tr transformer
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭50−54852（ＪＰ，Ａ) 特開 平４−121034（ＪＰ，Ａ) 特開 平８−154349（ＪＰ，Ａ) 特開 平３−60343（ＪＰ，Ａ) 特開 昭62−221834（ＪＰ，Ａ) 実開 平５−43731（ＪＰ，Ｕ) 実公 昭54−41942（ＪＰ，Ｙ１) 実公 平７−21074（ＪＰ，Ｙ２) (58)調査した分野(Int.Cl.7，ＤＢ名) H02J 9/06 501 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-50-54852 (JP, A) JP-A-4-121034 (JP, A) JP-A-8-154349 (JP, A) JP-A-3-154 JP-A-62-221834 (JP, A) JP-A-5-43371 (JP, U) JP-A-54-41942 (JP, Y1) JP-A-7-21074 (JP, Y2) (58) Field surveyed (Int. Cl. 7 , DB name) H02J 9/06 501
Claims (1)
の電源の出力端との間に接続され、一方の電源により操
作コイルが励磁されるａ接点とｂ接点とを有し、そのａ
接点を一方の電源の出力端と変圧器の一次側巻線との間
に接続し、そのｂ接点を他方の電源の出力端と変圧器の
一次側巻線との間に接続した電源切替回路において、 変圧器の一次側巻線を、一方の巻線回路と他方の巻線回
路とを互いに共通接続する共通線を介して分割された２
回路とし、一方の巻線回路と一方の電源とを前記ａ接点
を介して接続するとともに、他方の巻線回路と他方の電
源とを前記ｂ接点を介して接続したことを特徴とする電
源切替回路。(57) [Claim 1] A primary winding of a transformer and two different windings
And an a-contact and a b-contact, the operation coil of which is energized by one of the power supplies.
A power supply switching circuit having a contact connected between an output terminal of one power supply and a primary winding of a transformer, and a b contact connected between an output terminal of the other power supply and a primary winding of the transformer. The primary winding of the transformer is connected to one winding circuit and the other winding
Divided over a common line commonly connecting the road from each other 2
A power supply switching circuit, wherein one winding circuit and one power supply are connected via the a contact, and the other winding circuit and the other power supply are connected via the b contact. circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP00317097A JP3487487B2 (en) | 1997-01-10 | 1997-01-10 | Power switching circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP00317097A JP3487487B2 (en) | 1997-01-10 | 1997-01-10 | Power switching circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10201134A JPH10201134A (en) | 1998-07-31 |
| JP3487487B2 true JP3487487B2 (en) | 2004-01-19 |
Family
ID=11549915
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP00317097A Expired - Fee Related JP3487487B2 (en) | 1997-01-10 | 1997-01-10 | Power switching circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3487487B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111711193A (en) * | 2020-07-17 | 2020-09-25 | 中车大连机车车辆有限公司 | Power supply control method and device for multi-connection electric locomotive |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7352082B2 (en) * | 2004-02-10 | 2008-04-01 | Liebert Corporation | Transfer switch device and method |
| JP4792341B2 (en) * | 2006-07-12 | 2011-10-12 | 株式会社リコー | Fixing device and warm-up method of image forming apparatus |
| CN106655156A (en) * | 2016-10-18 | 2017-05-10 | 国网山东省电力公司烟台供电公司 | Automatic load control terminal switching device of dual-power-supply user |
-
1997
- 1997-01-10 JP JP00317097A patent/JP3487487B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111711193A (en) * | 2020-07-17 | 2020-09-25 | 中车大连机车车辆有限公司 | Power supply control method and device for multi-connection electric locomotive |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH10201134A (en) | 1998-07-31 |
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