Patent Publication Number: US-9425012-B2

Title: Electromagnetic operation device for vacuum circuit breaker

Description:
TECHNICAL FIELD 
     This invention relates to “an electromagnetic operation device for a vacuum circuit breaker” that controls a contact-switching operation of a vacuum switch tube used in the vacuum circuit breaker, by means of a driving force using electromagnetic force, and in more particular, relates to an electromagnetic operation device for a vacuum circuit breaker that can suppress change in speed of the contact switching operation, even if a temperature change occurs in a drive coil and/or a drive capacitor constituting the electromagnetic operation device. 
     BACKGROUND ART 
       FIG. 6  is a diagram showing an electromagnetic operation device for a power switching apparatus (vacuum circuit breaker) disclosed for example in Japanese Domestic Re-Publication No. WO2005/111641 (Patent Document 1). 
     Using  FIG. 6 , a configuration of the conventional electromagnetic operation device for a vacuum circuit breaker will be described. 
     A vacuum switch tube (called also as a vacuum valve)  50  constituting the vacuum circuit breaker has a switching contact  51  accommodated in a vacuum vessel. The switching contact  51  is composed of a fixed contact  51   a  and a movable contact  51   b , and in the contact open state, the fixed contact  51   a  and the movable contact  51   b  are placed opposite to each other with a given space therebetween. 
     To the movable contact  51   b , a driving shaft  52  is fixed, so that the movable contact  51   b  and the driving shaft  52  constitute a movable section. The movable section is coupled to a movable core  61  in an electromagnetic operation mechanism  60  through a contact pressure spring and a spring seat  54 . 
     The electromagnetic operation mechanism  60  has a movable core  61 , a closing drive coil  62  and an opening drive coil  63 . 
     The closing drive coil  62  serves to drive the movable contact  51   b  to thereby achieve the contact closed state, and the opening drive coil  63  serves to drive the movable contact  51   b  to thereby achieve the contact open state. 
     The closing drive coil  62  and the opening drive coil as driving magnetic coils are arranged in axial direction of the movable core  61  with a given distance therebetween. The movable core  61  is disposed centrally in the closing drive coil  62  and the opening drive coil  63 , and movably in its axial direction. 
     A driving power supply unit  70  has a closing drive capacitor  71 , an opening drive capacitor  72 , a close command switch  73  and an open command switch  74 . 
     When the close command switch  73  is turned on, a voltage charged in the closing drive capacitor  71  is applied to the closing drive coil  62 , so that a current flows through the closing drive coil  62  to thereby cause a drive toward the contact closed state. Meanwhile, when the open command switch  74  is turned on, a voltage charged in the opening drive capacitor  72  is applied to the opening drive coil  63 , so that a current flows through the opening drive coil  63  to thereby cause a drive toward the contact open state. 
     Note that, in  FIG. 6 , shown at  81  is a connection line, at  82  is a current measuring device, and at  83  is a contact depletion amount measuring device; however, since they are not relevant to the present invention, their description is omitted here. 
     A status recognition device disclosed in the above Patent Document 1, is to be equipped in the electromagnetic operation device which comprises a fixed core, a movable core configured movably with respect to the fixed core, and a magnetic coil that causes to move the movable core being magnetically excited by a driving power supply, to thereby drive an operational target instrument (vacuum switch tube) being coupled to the movable core, wherein the status recognition device includes a measuring means for measuring a current flowing through the magnetic coil or a voltage generated in the magnetic coil, and an exploring means for acquiring information about a change in a waveform outputted from the measuring means, to thereby estimate a status of the operational target instrument or the electromagnetic operation device on the basis of the information about the change from the exploring means. 
     In Patent Document 1, however, there is no description as to “occurrence of change in speed of the contact switching operation, due to a change in current flowing through the magnetic coil” that is caused by a temperature change of the magnetic coil (the opening drive coil, the closing drive coil) or the capacitor (the opening drive capacitor, the closing drive capacitor) in the electromagnetic operation device for a vacuum circuit breaker using the vacuum switch tube, as well as to “suppression of change in speed of the contact switching operation”. 
     Meanwhile,  FIG. 7  is a diagram showing a configuration of an electromagnetic-repulsion drive switching device disclosed for example in Japanese Domestic Re-Publication No. W001/031667 (Patent Document 2). 
     The electromagnetic-repulsion drive switching device shown in  FIG. 7  (that is, an electromagnetic operation device for a vacuum circuit breaker), is an electromagnetic-repulsion drive switching device which is configured to include a closing drive coil  101  and an opening drive coil  102  that are arranged opposite to an electrically-conductive repulsion member; and to make contact or separation between a fixed contact and a movable contact by way of an electromagnetic repulsion force produced between either one of the coils  101 ,  102  and the repulsion member, when a drive current is supplied selectively to either one of the coils  101 ,  102  from a capacitor  104  charged at a predetermined voltage by a charging power supply  103 ; wherein a voltage control means  105  is provided that controls an output voltage of the charging power supply  103  so that a peak value of the drive current falls in a predetermined range, against a temperature change of the capacitor  104 . 
     In Patent Document 2, there is described that “the contact is operated stably and accurately by providing the voltage control means to thereby control a peak value of the drive current to fall in the predetermined range even if the temperature of the capacitor changes”. 
     That is, in Patent Document 2, there is described that change in speed of the contact switching operation is suppressed by controlling the magnitude of current flowing through the closing drive coil or the opening drive coil according to a temperature change of the drive capacitor for causing a current to flow through the closing drive coil or the opening drive coil. 
     However, even in Patent Document 2, there is no description as to suppression of change in speed of the contact switching operation caused by a change in surrounding temperature of the magnetic coil (the opening drive coil, the closing drive coil) in an electromagnetic operation device for a vacuum circuit breaker using a vacuum switch tube.
     Patent Document 1: Japanese Domestic Re-Publication No. WO2005/111641   Patent Document 2: Japanese Domestic Re-Publication No. WO01/031667   

     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     For vacuum circuit breakers, an operational duty (operation specification) is defined in the standard (JEC-2300), in which it is required to make close/open (that is, a closed/open state operation) for three cycles (50 msec). 
     It is noted that “JEC” represents “Japanese Electro-technical Committee”. 
     In normal use conditions of the vacuum circuit breakers, in order to fulfill the operational duty, energizing the drive coil is controlled by a constant period of time. 
     However, because of variation in ambient temperature, the resistance value of the drive coil in the electromagnetic operation device changes, so that the current value flowing through the drive coil changes. This makes change in operation speed of the movable contact in the vacuum switch tube constituting the vacuum circuit breaker. 
     What is particularly problematic is that “when the surrounding ambient temperature becomes lower, the temperature of the closing drive coil also becomes lower, so that the resistance value of the drive coil becomes smaller thereby making larger the value of the current flowing through the closing drive coil.” 
     When the value of the current flowing through the closing drive coil becomes larger, the movable contact is caused to move faster, so that contact touching (making contact between the movable contact and the fixed contact in the vacuum switch tube, that is, a closing operation) is achieved faster than that in the normal condition. 
     On the other hand, when the surrounding ambient temperature becomes higher, the temperature of the opening drive coil also becomes higher, so that the resistance value of the opening drive coil becomes larger thereby making smaller the value of the current flowing through the opening drive coil. 
     When the value of the current flowing through the opening drive coil becomes smaller, the movable contact is caused to move slower, so that the opening operation becomes slower than that in the normal condition. 
     In normal use conditions of the vacuum circuit breakers, energizing the closing drive coil and the opening drive coil is controlled by a constant period of time. 
     Thus, there is a problem that when the contact operation at the time of closing becomes faster than normal or the contact operation at the time of opening becomes slower than normal, the whole time to make close/open of the contact becomes longer, so that the operational duty of making close/open for three cycles (50 msec) could not be fulfilled. 
     Meanwhile, the charging capacity of each of the closing drive capacitor and the opening drive capacitor changes when its temperature becomes lower. For example, when the temperature becomes lower and thus the charging capacity becomes smaller, the charged energy becomes smaller, so that the current flowing through the closing drive coil and the opening drive coil becomes decreased to thereby affect the operation speed of the movable contact. 
       FIG. 8  is image diagrams for illustrating a problem at the time of closing operation of a conventional vacuum circuit breaker, in which shown at  FIG. 8( a )  is a diagram for illustrating a state of the contact under operation when the temperature of the closing drive coil becomes lower. 
     The solid line A shown in  FIG. 8( a )  is a transition line of a position of the contact when the temperature of the closing drive coil is a normal temperature, and the broken line B is a transition line of a position of the contact when the temperature of the closing drive coil becomes lower, so that the contact touching (closing operation) becomes faster. 
     As shown in  FIG. 8( a ) , according to the conventional vacuum circuit breaker, when the temperature of the closing drive coil becomes lower and thus the contact touching becomes faster, the whole time to make close/open of the contact becomes longer, so that the operational duty of “making close/open for three cycles (50 msec)” can not be fulfilled. 
     Further, when there is a change in the temperature of the drive capacitor for applying its charged voltage to the closing drive coil so as to cause a current to flow therethrough, since the value of the current flowing through the closing drive coil changes, the speed for contact touching changes to thereby affect the whole time to make close/open of the contact. Thus, there is a risk that the operational duty of “making close/open for three cycles (50 msec)” can not be fulfilled. 
     It is noted that shown at  FIG. 8( b )  are a changing state of the current flowing through the closing coil (closing drive coil) and a changing state of the current flowing through the opening coil (opening drive coil). 
     Meanwhile, as described above, when the surrounding temperature becomes higher, the temperature of the opening drive coil also becomes higher, so that the resistance value of the opening drive coil becomes larger thereby making smaller the value of the current flowing through the drive coil. 
     When the value of current flowing through the opening drive coil becomes smaller, the movable contact is caused to move slower at the time of opening operation, so that the opening operation becomes slower than that of the normal condition. 
     In normal use conditions of the vacuum circuit breakers, energizing the opening drive coil is also controlled by a constant period of time. 
     Thus, there is also a problem that when the operation of the contact at the time of opening becomes slower than normal, the whole time to make close/open of the contact becomes longer, so that the operational duty of making close/open for three cycles (50 msec) can not be fulfilled. 
       FIG. 9  is image diagrams for illustrating a problem at the time of opening operation of the conventional vacuum circuit breaker, in which shown at  FIG. 9( a )  is a diagram for illustrating a state of the contact under operation when the temperature of the opening drive coil becomes lower. 
     The solid line A shown in  FIG. 9( a )  is a transition line of a position of the contact when the temperature of the opening drive coil is a normal temperature, and the broken line B is a transition line of a position of the contact when the temperature of the opening drive coil becomes higher, so that the opening operation becomes slower. 
     As shown in  FIG. 9( a ) , according to the conventional vacuum circuit breaker, when the temperature of the opening drive coil becomes higher and thus the opening operation becomes slower, the whole time to make close/open of the contact becomes longer, so that the operational duty of “making close/open for three cycles (50 msec)” can not be fulfilled. 
     It is noted that shown at  FIG. 9( b )  are a changing state of the current flowing through the closing coil (closing drive coil) and a changing state of the current flowing through the opening coil (opening drive coil). 
     This invention has been made to solve such conventional problems, and an object thereof is to provide an electromagnetic operation device for a vacuum circuit breaker, which is capable of suppressing change in speed of the contact switching operation by accurately controlling the change in the current flowing through the closing drive coil and/or the opening drive coil, even if the temperature of either or both of the closing drive coil and the opening drive coil changes and even if the temperature of the closing drive capacitor or the opening drive capacitor changes, whereby the operational duty of making close/open for three cycles (50 msec) defined in the standard (JEC-2300) can be fulfilled, 
     Means for Solving the Problems 
     An electromagnetic operation device for a vacuum circuit breaker according to the invention is such an electromagnetic operation device for a vacuum circuit breaker, which controls by its electromagnetic operation, a speed of contact switching operation of a vacuum switch tube used in the vacuum circuit breaker, said electromagnetic operation device comprising a closing drive coil for the vacuum switch tube and a first temperature sensor that measures a temperature surrounding the closing drive coil, wherein a current caused to flow through the closing drive coil is controlled based on the temperature measured by the first temperature sensor. 
     Further, another electromagnetic operation device for a vacuum circuit breaker according to the invention is such an electromagnetic operation device for a vacuum circuit breaker, which controls by its electromagnetic operation, a speed of contact switching operation of a vacuum switch tube used in the vacuum circuit breaker, said electromagnetic operation device comprising an opening drive coil for the vacuum switch tube and a third temperature sensor that measures a temperature surrounding the opening drive coil, wherein a current caused to flow through the opening drive coil is controlled based on the temperature measured by the third temperature sensor. 
     Further, another electromagnetic operation device for a vacuum circuit breaker according to the invention is such an electromagnetic operation device for a vacuum circuit breaker, which controls by its electromagnetic operation, a speed of contact switching operation of a vacuum switch tube used in the vacuum circuit breaker, said electromagnetic operation device comprising a closing drive coil for the vacuum switch tube and a first temperature sensor that measures a temperature surrounding the closing drive coil, wherein a current caused to flow through the closing drive coil is controlled based on the temperature measured by the first temperature sensor; and further comprising an opening drive coil for the vacuum switch tube and a third temperature sensor that measures a temperature surrounding the opening drive coil, wherein a current caused to flow through the opening drive coil is controlled based on the temperature measured by the third temperature sensor. 
     Effect of the Invention 
     According to the invention, even if the temperature of the closing drive coil and/or the opening drive coil changes, it is possible to suppress change in the value of the current flowing through the closing drive coil and/or the opening drive coil. Thus, it becomes possible to provide an “electromagnetic operation device for a vacuum circuit breaker” that can fulfill the operational duty of making close/open for three cycles (50 msec) defined in the standard (JEC-2300) for vacuum circuit breakers. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing a configuration of an electromagnetic operation device for a vacuum circuit breaker, according to Embodiment 1. 
         FIG. 2  is a graph showing a change in a surrounding temperature of a drive coil and a change in an actual temperature thereof. 
         FIG. 3  is a functional illustration diagram schematically showing functions of a first temperature-correction indication unit. 
         FIG. 4  is a functional illustration diagram schematically showing functions of a second temperature-correction indication unit. 
         FIG. 5  is a diagram showing a configuration of an electromagnetic operation device for a vacuum circuit breaker, according to Embodiment 3. 
         FIG. 6  is a diagram showing a configuration of an electromagnetic operation device for a vacuum circuit breaker, disclosed in Patent Document 1. 
         FIG. 7  is a diagram showing a configuration of an electromagnetic-repulsion drive switching device disclosed in Patent Document 2. 
         FIG. 8  is image diagrams for illustrating a problem at the time of closing operation of a conventional vacuum circuit breaker. 
         FIG. 9  is image diagrams for illustrating a problem at the time of opening operation of a conventional vacuum circuit breaker. 
     
    
    
     MODES FOR CARRYING OUT THE INVENTION 
     Hereinafter, embodiments for carrying out the invention will be described based on the drawings. 
     Note that, in the respective figures, the same symbols represent the same or equivalent objects. 
     Embodiment 1 
       FIG. 1  is a diagram showing a schematic configuration of an electromagnetic operation device for a vacuum circuit breaker, according to Embodiment 1. 
     In  FIG. 1 , shown at  10  is a power supply (AC power supply); at  11  is a closing charging circuit; at  12  an opening charging circuit; at  21  a closing drive capacitor; at  22  an opening drive capacitor; at  31  a closing drive coil; at  32  an opening drive coil; at  41  a first energization unit; at  42  a second energization unit; at  201  a first temperature sensor; at  202  a second temperature sensor; at  203  a third temperature sensor; at  204  a fourth temperature sensor; at  300  a first temperature-correction indication unit; and, at  400  a second temperature-correction indication unit. 
     Note that the closing drive coil  31  corresponds to the closing drive coil  62  in  FIG. 6  or the closing drive coil  101  in  FIG. 7 , and the opening drive coil  32  corresponds to the opening drive coil  63  in  FIG. 6  or the opening drive coil  102  in  FIG. 7 . 
     First, description will be made to a case of executing a closing operation. 
     The closing charging circuit  11  to which a power supply voltage is applied from the power supply  10 , generates a DC voltage (charge voltage) on the basis of a charge-voltage indication value indicated from the first temperature-correction indication unit  300  as described later, to thereby charge the closing drive capacitor  21 . Then, the voltage charged in the closing drive capacitor  21  is applied to the closing drive coil  31 , so that a current flows through the closing drive coil  31  across the first energization unit  41  which is a switch mechanism. That is, by turning on the first energization unit  41  according to a closing instruction, a current flows through the closing drive coil  31 , so that the contact in a vacuum switch tube (not shown) of the vacuum circuit breaker is driven toward its closed state. 
     In order that the contact operation of the vacuum circuit breaker fulfills the operation specification (making close/open for three cycles) defined in the standard (JEC-2300), the time period to reach the closed state from the open state of the contact in the vacuum switch tube used in the vacuum circuit breaker (contact closing time period), has to be suppressed from changing due to change in the temperature surrounding the closing drive coil  31  (for example, from becoming too fast). 
     Thus, in this embodiment, the first temperature sensor  201  for measuring the temperature surrounding the closing drive coil  31  is arranged around (near) the closing drive coil  31 . The temperature measured by the first temperature sensor  201  is inputted to the first temperature-correction indication unit  300 . 
     Meanwhile, when the temperature surrounding the closing drive capacitor  21  changes, the value of the voltage to be charged in the closing drive capacitor  21  is influenced to change, and as a result, the value of the current flowing through the closing drive coil  31  changes. 
     That is, when the temperature surrounding the closing drive capacitor  21  changes, the value of the current flowing through the closing drive coil  31  changes too. 
     Thus, in this embodiment, the second temperature sensor  202  for measuring the temperature surrounding the closing drive capacitor  21  is arranged around (near) the closing drive capacitor  21 . The temperature measured by the second temperature sensor  202  is inputted to the first temperature-correction indication unit  300 . 
     It is noted that in this embodiment, since the first temperature sensor  201  is arranged around the closing drive coil  31 , a difference emerges between the temperature measured by the first temperature sensor  201  and the actual temperature of the closing drive coil  31 . That is, as shown in  FIG. 2 , the change in the actual temperature (indicated by the broken line B) of the drive coil (closing drive coil  31 ) is delayed from the change in the surrounding temperature (indicated by the solid line A) of the closing drive coil  31  measured by the first temperature sensor  201 . 
     Further, since the second temperature sensor  202  is arranged around the closing drive capacitor  21 , the change in the actual temperature of the closing drive capacitor is delayed from the change in the surrounding temperature of the closing drive capacitor  21  measured by the second temperature sensor  202 , as similar to the case of delay in the measured temperature by the first temperature sensor  201 . 
     Thus, in consideration of these delays in measured temperature, the first temperature-correction indication unit  300  determines a charge-voltage indication value for the closing charging circuit  11 , on the basis of values of temperatures measured by the first temperature sensor  201  and the second temperature sensor  202  and their corresponding predetermined correction tables (or predetermined calculation formulae). 
     Then, the first temperature-correction indication unit  300  indicates to the closing charging circuit  11  through a D/A converter  310 , a charge voltage (that is, a voltage value to be charged in the closing drive capacitor  21 ), so that the closing charging circuit  11  charges the closing drive capacitor  21  to the indicated voltage. 
       FIG. 3  is a functional illustration diagram schematically showing functions of the first temperature-correction indication unit  300 . 
     In  FIG. 3 , shown at  301  is a measured temperature measured by the first temperature sensor  201  arranged around the closing drive coil  31 ; at  302  is a measured temperature measured by the second temperature sensor  202  arranged around the closing drive capacitor  21 ; at  303  is a first correction table for correcting the measured temperature measured by the first temperature sensor  201 ; and at  304  is a second correction table for correcting the measured temperature measured by the second temperature sensor  202 . 
     As shown in  FIG. 3 , in the first temperature-correction indication unit  300 , the temperature measured by the first temperature sensor  201  (that is, measured temperature by the first temperature sensor  301 ) is corrected by the first temperature-correction table  303 , and the temperature measured by the second temperature sensor  202  (that is, measured temperature by the second temperature sensor  302 ) is corrected by the second temperature-correction table  304 . 
     A predetermined reference voltage (reference DC voltage at a predetermined temperature)  305 , is firstly corrected by a first correction factor  306  produced from the first temperature-correction table  303 . Further, the DC voltage corrected by the first correction factor  306  is corrected by a second correction factor  307  produced from the second temperature-correction table  304 . Then, the DC voltage corrected by the first correction factor  306  and the second correction factor  307  is converted by the D/A converter  310  and is then outputted from the first temperature-correction indication unit  300 , as the charge-voltage indication value for the closing charging circuit  11  (that is, as a D/A output voltage  308 ). The closing charging circuit  11  charges the closing drive capacitor  21  according to the charge-voltage indication value indicated from the first temperature-correction indication unit  300 . 
     Next, description will be made to a case of executing an opening operation. 
     The opening charging circuit  12  to which a power supply voltage is applied from the power supply  10 , generates a DC voltage (charge voltage) on the basis of a charge-voltage indication value indicated from the second temperature-correction indication unit  400 , to thereby charge the opening drive capacitor  22 . Then, the voltage charged in the opening drive capacitor  22  is applied to the opening drive coil  32 , so that a current flows through the opening drive coil  32  across the second energization unit  42  which is a switch mechanism. 
     That is, by turning on the second energization unit  42  according to an opening instruction, a current flows through the opening drive coil  32 , so that the contact in the vacuum switch tube (not shown) of the vacuum circuit breaker is driven toward its open state. 
     In order that the contact operation of the vacuum circuit breaker fulfills the operation specification (making close/open for three cycles) defined in the standard (JEC-2300), also in the case of opening operation, the time period to reach the open state from the closed state of the contact in the vacuum switch tube used in the vacuum circuit breaker (contact opening time period), has to be suppressed from changing due to change in the temperature surrounding the opening drive coil  32  (for example, from becoming too slow). 
     Thus, in this embodiment, the third temperature sensor  203  for measuring the temperature surrounding the opening drive coil  32  is arranged around (near) the opening drive coil  32 . The temperature measured by the third temperature sensor  203  is inputted to the second temperature-correction indication unit  400 . 
     Meanwhile, when the temperature surrounding the opening drive capacitor  22  changes, the value of the voltage to be charged in the opening drive capacitor  22  is influenced to change, and as a result, the value of the current flowing through the opening drive coil  32  changes. 
     Thus, in this embodiment, the fourth temperature sensor  204  for measuring the temperature surrounding the opening drive capacitor  22  is arranged around (near) the opening drive capacitor  22 . The temperature measured by the fourth temperature sensor  204  is inputted to the second temperature-correction indication unit  400 . 
     It is noted that in this embodiment, since the third temperature sensor  203  is arranged around the opening drive coil  32 , a difference emerges between the temperature measured by the third temperature sensor  203  and the actual temperature of the opening drive coil  32 . That is, as shown in  FIG. 2 , the change in the actual temperature (indicated by the broken line B) of the drive coil (opening drive coil  32 ) is delayed from the change in the surrounding temperature (indicated by the solid line A) of the opening drive coil  32  measured by the third temperature sensor  203 . 
     Further, since the fourth temperature sensor  204  is arranged around the opening drive capacitor  22 , the change in the actual temperature of the opening drive capacitor is delayed from the change in the surrounding temperature of the opening drive capacitor  22  measured by the fourth temperature sensor  204 , as similar to the case of delay in the measured temperature by the third temperature sensor  203 . 
     Thus, in consideration of these delays in measured temperature, the second temperature-correction indication unit  400  determines a charge-voltage indication value for the opening charging circuit  12 , on the basis of values of temperatures measured by the third temperature sensor  203  and the fourth temperature sensor  204  and their corresponding predetermined correction tables (or predetermined calculation formulae). 
     Then, the second temperature-correction indication unit  400  indicates to the opening charging circuit  12  through a D/A converter  410 , a charge voltage (that is, a voltage value to be charged in the opening drive capacitor  22 ), so that the opening charging circuit  12  charges the opening drive capacitor  22  to the indicated voltage. 
       FIG. 4  is a functional illustration diagram schematically showing functions of the second temperature-correction indication unit  400 . 
     In  FIG. 4 , shown at  401  is a measured temperature measured by the third temperature sensor  203  arranged around the opening drive coil  32 ; at  402  is a measured temperature measured by the fourth temperature sensor  204  arranged around the opening drive capacitor  22 ; at  403  is a third correction table for correcting the measured temperature measured by the third temperature sensor  203 ; and at  404  is a fourth correction table for correcting the measured temperature measured by the fourth temperature sensor  204 . 
     As shown in  FIG. 4 , in the second temperature-correction indication unit  400 , the temperature measured by the third temperature sensor  203  (that is, measured temperature by the third temperature sensor  401 ) is corrected by the third temperature-correction table  403 , and the temperature measured by the fourth temperature sensor  204  (that is, measured temperature by the fourth temperature sensor  402 ) is corrected by the fourth temperature-correction table  404 . 
     A predetermined reference voltage (reference DC voltage at a predetermined temperature)  405 , is firstly corrected by a third correction factor  406  produced from the third temperature-correction table  403 . Further, the DC voltage corrected by the third correction factor  406  is corrected by a second correction factor  407  produced from the fourth temperature-correction table  404 . 
     Then, the DC voltage corrected by the third correction factor  406  and the fourth correction factor  407  is converted by the D/A converter  410  and is then outputted from the second temperature-correction indication unit  400 , as the charge-voltage indication value for the opening charging circuit  12  (that is, as a D/A output voltage  408 ). 
     The opening charging circuit  12  charges the opening drive capacitor  22  according to the charge-voltage indication value indicated from the second temperature-correction indication unit  400 . 
     Next, description will be made to an influence by the temperature change of the closing drive capacitor or the opening drive capacitor, effected on the operation speed of the movable contact at the time of closing or opening. 
     When the temperature becomes lower, each capacity of the closing drive capacitor  21  and the opening drive capacitor  22  becomes smaller, so that each output voltage of the closing drive capacitor  21  and the opening drive capacitor  22  becomes lower. 
     This decreases the current flowing through the closing drive coil  31  or the opening drive coil  32 , so that the operation speed of the movable contact at the time of closing or opening becomes slower. 
     With respect to the closing operation, the amount of change in the current flowing through the closing drive capacitor  31 , is actually larger in the case where the contact moves faster due to decrease in the resistance value of the closing drive coil  31  when the temperature of the closing drive coil  31  becomes lower, than in the case where the contact speed becomes slower due to decrease in the capacity of the closing drive capacitor  21  when its temperature becomes lower. 
     Thus, a changed portion in the contact speed that is attributed to the change in the capacity of the closing drive capacitor  21 , will be disappeared. 
     However, when the charge voltage for the closing drive capacitor  21  is corrected based solely on the temperature change of the closing drive coil  31 , an error occurs due to a capacity changed portion of the closing drive capacitor  21 . 
     The same applies to the opening operation. 
     In this embodiment, the charge voltage for the closing drive capacitor  21  is corrected based on both the temperature change of the closing drive coil  31  measured by the first temperature sensor  201  and the temperature change of the closing drive capacitor  21  measured by the second temperature sensor  202 . 
     Likewise, the charge voltage for the opening drive capacitor  22  is corrected based on both the temperature change of the opening drive coil  32  measured by the third temperature sensor  203  and the temperature change of the opening drive capacitor  22  measured by the fourth temperature sensor  204 . 
     By doing so, it is possible to stably and accurately control the current flowing through the closing drive coil  31 , even if the surrounding temperature of the closing drive coil  31  or the closing drive capacitor  21  changes. Likewise, it is possible to stably and accurately control the current flowing through the opening drive coil  32 , even if the surrounding temperature of the opening drive coil  32  or the opening drive capacitor  22  changes. 
     Accordingly, the closing operation speed and the opening operation speed of the switching contact can be accurately fallen within a predetermined range. 
     That is, it becomes possible to stably and accurately control the closing operation and/or the opening operation of the contact so that the vacuum circuit breaker fulfills the operational duty (that is, making close/open for three cycles). 
     It is noted here that in the above description, such cases are described, where the first temperature sensor  201  for measuring the surrounding temperature of the closing drive coil  31  is arranged around the closing drive coil  31 , and the second temperature sensor  202  for measuring the surrounding temperature of the closing drive capacitor  21  is arranged around the closing drive capacitor  21 , so that the charge voltage for the closing drive capacitor  21  is corrected based on the temperatures measured by both of the sensors; and where the third temperature sensor  203  for measuring the surrounding temperature of the opening drive coil  32  is arranged around the opening drive coil  32 , and the fourth temperature sensor  204  for measuring the surrounding temperature of the opening drive capacitor  22  is arranged around the opening drive capacitor  22 , so that the charge voltage for the opening drive capacitor  22  is corrected based on the temperatures measured by both of the sensors. 
     However, it is allowable not to arrange the second temperature sensor  202  for measuring the surrounding temperature of the closing drive capacitor  21  around the closing drive capacitor  21 , and thus to provide a configuration in which the first temperature sensor  201  for measuring the surrounding temperature of the closing drive coil  31  is solely arranged around the closing drive coil  31 . Also, it is allowable not to arrange the fourth temperature sensor  204  for measuring the surrounding temperature of the opening drive capacitor  22  around the opening drive capacitor  22 , and thus to provide a configuration in which the third temperature sensor  203  for measuring the surrounding temperature of the opening drive coil  32  is solely arranged around the opening drive coil  32 . 
     In this instance, although an accuracy for correcting the charge voltage for the closing drive capacitor  21  or the opening drive capacitor  22  is somewhat degraded, it is possible to control the current flowing through the closing drive coil  31  or the opening drive coil  32  to have an almost constant value. 
     That is, the contact switching speed can be suppressed to be almost constant even without arranging the second temperature sensor  202  or the fourth temperature sensor  204 , so that the operational duty of making close/open for three cycles defined in the standard (JEC-2300) can be fulfilled. 
     It is noted that, in vacuum circuit breakers, when the contact switching speed of the vacuum switch tube becomes faster, the impact at the time of contact switching becomes greater, thus shortening the life duration of the vacuum switch tube, whereas when the contact switching speed becomes slower, the closing operation of the vacuum circuit breaker becomes unstable, thus causing a state incapable of keeping a power-throw. 
     According to this embodiment, however, it is possible to cause switching of the contact of the vacuum circuit breaker at an optimum speed (that is, a least one of the speed required to fulfill the operational duty) regardless of change in the temperature of the closing drive coil  31 , the opening drive coil  32 , the closing drive capacitor  21  or the opening drive capacitor  22 . Thus, it becomes possible to reduce too-much impact at the time of contact switching, to thereby prolong the life duration of the vacuum switch tube in the vacuum circuit breaker. 
     By the way, in the above description, such a case is described, where the first temperature sensor  201  for measuring the surrounding temperature of the closing drive coil  31  is arranged around the closing drive coil  31 , and the second temperature sensor  202  for measuring the surrounding temperature of the closing drive capacitor  21  is arranged around the closing drive capacitor  21 , so that the charge voltage for the closing drive capacitor  21  is corrected based on the temperatures measured by both of the sensors. 
     Further described is such a case where the third temperature sensor  203  for measuring the surrounding temperature of the opening drive coil  32  is arranged around the opening drive coil  32 , and the fourth temperature sensor  204  for measuring the surrounding temperature of the opening drive capacitor  22  is arranged around the opening drive capacitor  22 , so that the charge voltage for the closing drive capacitor  21  is corrected based on the temperatures measured by both of the sensors. 
     As described above, an electromagnetic operation device for a vacuum circuit breaker according to this embodiment, is such an electromagnetic operation device for a vacuum circuit breaker which controls by its electromagnetic operation, a speed of contact switching operation of a vacuum switch tube used in the vacuum circuit breaker, said electromagnetic operation device including the closing drive coil  31  for the vacuum switch tube, and the first temperature sensor  201  that measures the temperature surrounding the closing drive coil  31 , wherein a current caused to flow through the closing drive coil  31  is controlled based on the temperature measured by the first temperature sensor  201 . 
     Thus, the current flowing through the closing drive coil  31  can be controlled even if the surrounding temperature of the closing drive coil  31  changes; therefore, it is possible to control the closing operation speed of the switching contact to fall within a predetermined range, and thus to move the contact so that the vacuum circuit breaker fulfills the operational duty (that is, making close/open for three cycles). 
     Further, an electromagnetic operation device for a vacuum circuit breaker according to this embodiment, is such an electromagnetic operation device for a vacuum circuit breaker which controls by its electromagnetic operation, a speed of contact switching operation of a vacuum switch tube used in the vacuum circuit breaker, said electromagnetic operation device including the opening drive coil  32  for the vacuum switch tube, and the third temperature sensor  203  that measures the temperature surrounding the opening drive coil  32 , wherein a current caused to flow through the opening drive coil  32  is controlled based on the temperature measured by the third temperature sensor  203 . 
     Thus, the current flowing through the opening drive coil  32  can be controlled even if the surrounding temperature of the opening drive coil  32  changes; therefore, it is possible to control the opening operation speed of the switching contact to fall within a predetermined range, and thus to move the contact so that the vacuum circuit breaker fulfills the operational duty. 
     Further, an electromagnetic operation device for a vacuum circuit breaker according to this embodiment, is such an electromagnetic operation device for a vacuum circuit breaker which controls by its electromagnetic operation, a speed of contact switching operation of a vacuum switch tube used in the vacuum circuit breaker, said electromagnetic operation device including the closing drive coil  31  for the vacuum switch tube, and the first temperature sensor  201  that measures the temperature surrounding the closing drive coil  31 , wherein a current caused to flow through the closing drive coil  31  is controlled based on the temperature measured by the first temperature sensor  201 ; and said electromagnetic operation device further including the opening drive coil  32  for the vacuum switch tube, and the third temperature sensor  203  that measures the temperature surrounding the opening drive coil  32 , wherein a current caused to flow through the opening drive coil  32  is controlled based on the temperature measured by the third temperature sensor  203 . 
     Thus, the currents flowing through the closing drive coil  31  and the opening drive coil  32  can be controlled even if the surrounding temperature of the closing drive coil  31  or the opening drive coil  32  changes; therefore, it is possible to control the closing operation speed and the opening operation speed of the switching contact to fall within predetermined ranges, and thus to move the contact so that the vacuum circuit breaker surely fulfills the operational duty. 
     Further, an electromagnetic operation device for a vacuum circuit breaker according to this embodiment, is such an electromagnetic operation device for a vacuum circuit breaker which controls by its electromagnetic operation, a speed of contact switching operation of a vacuum switch tube used in the vacuum circuit breaker, said electromagnetic operation device including the closing drive coil  31  for the vacuum switch tube, the closing drive capacitor  21  for causing a contact-closing drive current to flow through the closing drive coil  31 , the closing charging circuit  11  that charges the closing drive capacitor  21 , the first temperature sensor  201  that measures the temperature surrounding the closing drive coil  31 , and the first temperature-correction indication unit  300  that indicates to the closing charging circuit  11 , a charge voltage correction value for the closing drive capacitor  21 , on the basis of the temperature measured by the first temperature sensor  201 . 
     Since the first temperature-correction indication unit  300  indicates to the closing charging circuit  11 , a charge voltage correction value for the closing drive capacitor  21 , on the basis of the temperature measured by the first temperature sensor  201 , it is possible to accurately control the current flowing through the closing drive coil  31  even if the surrounding temperature of the closing drive coil  31  changes. 
     Further, in an electromagnetic operation device for a vacuum circuit breaker according to this embodiment, the second temperature sensor  202  is provided that measures the temperature surrounding the closing drive capacitor  21 , and the first temperature-correction indication unit  300  indicates to the closing charging circuit  11 , the charge voltage correction value for the closing drive capacitor  21 , on the basis of the temperatures measured by the first temperature sensor  201  and the second temperature sensor  202 . 
     Thus, it is possible to accurately control the current flowing through the closing drive coil  31  even if the surrounding temperatures of both of the closing drive coil  31  and the closing drive capacitor  21  change. 
     Further, an electromagnetic operation device for a vacuum circuit breaker according to this embodiment, is such an electromagnetic operation device for a vacuum circuit breaker which controls by its electromagnetic operation, a speed of contact switching operation of a vacuum switch tube used in the vacuum circuit breaker, said electromagnetic operation device including the opening drive coil  32  for the vacuum switch tube, the opening drive capacitor  22  for causing a contact-opening drive current to flow through the opening drive coil  32 , the opening charging circuit  12  that charges the opening drive capacitor  22 , the third temperature sensor  203  that measures the temperature surrounding the opening drive coil  32 , and the second temperature-correction indication unit  400  that indicates to the opening charging circuit  12 , a charge voltage correction value for the opening drive capacitor  22 , on the basis of the temperature measured by the third temperature sensor  203 . 
     Since the second temperature-correction indication unit  400  indicates to the opening charging circuit  12 , a charge voltage correction value for the opening drive capacitor  22 , on the basis of the temperature measured by the third temperature sensor  203 , it is possible to accurately control the current flowing through the opening drive coil  32  even if the surrounding temperature of the opening drive coil  32  changes. 
     Further, in an electromagnetic operation device for a vacuum circuit breaker according to this embodiment, the fourth temperature sensor  204  is provided that measures the temperature surrounding the opening drive capacitor  22 , and the second temperature-correction indication unit  400  indicates to the opening charging circuit  12 , the charge voltage correction value for the opening drive capacitor  22 , on the basis of the temperatures measured by the third temperature sensor  203  and the fourth temperature sensor  204 . 
     Thus, it is possible to accurately control the current flowing through the closing drive coil  31  even if the surrounding temperatures of both of the opening drive coil  32  and the opening drive capacitor  22  change. 
     Further, an electromagnetic operation device for a vacuum circuit breaker according to this embodiment, is such an electromagnetic operation device for a vacuum circuit breaker which controls by its electromagnetic operation, a speed of contact switching operation of a vacuum switch tube used in the vacuum circuit breaker, said electromagnetic operation device including the closing drive coil  31  for the vacuum switch tube, the closing drive capacitor  21  for causing a contact-closing drive current to flow through the closing drive coil  31 , the closing charging circuit  11  that charges the closing drive capacitor  21 , the first temperature sensor  201  that measures a temperature surrounding the closing drive coil  31 , the second temperature sensor  202  that measures a temperature surrounding the closing drive capacitor  21 , and the first temperature-correction indication unit  300  that indicates to the closing charging circuit  11 , a charge voltage correction value for the closing drive capacitor  21 , on the basis of the temperatures measured by the first temperature sensor  201  and the second temperature sensor  202 , and said electromagnetic operation device further including the opening drive coil  32  for the vacuum switch tube, the opening drive capacitor  22  for causing a contact-opening drive current to flow through the opening drive coil  32 , the opening charging circuit  12  that charges the opening drive capacitor  22 , the third temperature sensor  203  that measures a temperature surrounding the opening drive coil  32 , the fourth temperature sensor  204  that measures a temperature surrounding the opening drive capacitor  22 , and the second temperature-correction indication unit  400  that indicates to the opening charging circuit  12 , a charge voltage correction value for the opening drive capacitor  22 , on the basis of the temperatures measured by the third temperature sensor  203  and the fourth temperature sensor  204 . 
     Thus, it is possible to accurately control the current flowing through the closing drive coil  31  and the opening drive coil  32  even if the surrounding temperatures of the closing drive coil  31  and the closing drive capacitor  21  or the surrounding temperatures of the opening drive coil  32  and the opening drive capacitor  22  change. 
     Embodiment 2 
     In the foregoing Embodiment 1, description is made to the case where the first temperature sensor  201  for measuring the surrounding temperature of the closing drive coil  31  is arranged around the closing drive coil  31 , or the case where the third temperature sensor  203  for measuring the surrounding temperature of the opening drive coil  32  is arranged around the opening drive coil  32 , whereas, an electromagnetic operation device according to Embodiment 2 is characterized in that the first temperature sensor  201  is embedded in the closing drive coil  31  and the third temperature sensor  203  is embedded in the opening drive coil  32 . 
     This makes it possible to directly measure the temperature of the closing drive coil  31  or the opening drive coil  32 , and thus to enhance accuracy for correcting the charge voltage for the closing drive capacitor  21  or the opening drive capacitor  22  with respect to a change in the surrounding temperature. 
     That is, according to this embodiment, since the current flowing through the closing drive coil  31  or the opening drive coil  32  can be more accurately controlled, it becomes possible to suppress the closing operation speed of the switching contact to be within a predetermined range. 
     Embodiment 3 
       FIG. 5  is a diagram showing a configuration of an electromagnetic operation device for a vacuum circuit breaker, according to Embodiment 3. 
     In the foregoing Embodiment 1, the temperature of the closing drive coil  31  is measured by using the first temperature sensor  201  arranged around the closing drive coil  31  and the temperature of the opening drive coil  32  is measured by using the third temperature sensor  203  arranged around the opening drive coil  32 , whereas this embodiment is characterized in that, as shown in  FIG. 5 , a first temperature-measuring energization unit  43  is provided instead of using the first temperature sensor  201 , and a second temperature-measuring energization unit  44  is provided instead of the third temperature sensor  203 . 
     In this embodiment, a weak current is caused to flow through the closing drive coil  31  by the first temperature-measuring energization unit  43 . 
     Then, the first temperature-correction indication unit  300  determines the resistance value of the closing drive coil  31  by detecting a value of the voltage produced due to the weak current flowing through the closing drive coil  31 . 
     Because the resistance value of the closing drive coil  31  changes depending on its temperature, the first temperature-correction indication unit  300  determines the temperature of the closing drive coil  31  through calculation after determined the resistance value of the closing drive coil  31 . 
     The first temperature-correction indication unit  300  corrects the charge voltage for the closing drive capacitor  21  on the basis of both of the temperature of the closing drive coil  31  determined through calculation and the temperature of the closing drive capacitor  21  measured by the second temperature sensor  202 . 
     Likewise, in this embodiment, a weak current is caused to flow through the opening drive coil  32  by the second temperature-measuring energization unit  44 . 
     Then, the second temperature-correction indication unit  400  determines the resistance value of the opening drive coil  32  by detecting a value of the voltage produced due to the weak current flowing through the opening drive coil  32 . 
     Because the resistance value of the opening drive coil  32  changes depending on its temperature, the second temperature-correction indication unit  400  determines the temperature of the opening drive coil  32  through calculation after determined the resistance value of the opening drive coil  32 . 
     The second temperature-correction indication unit  400  corrects the charge voltage for the opening drive capacitor  22  on the basis of both of the temperature of the opening drive coil  32  determined through calculation and the temperature of the opening drive capacitor  22  measured by the fourth temperature sensor  204 . 
     As described above, an electromagnetic operation device according to this embodiment includes, instead of the first temperature sensor  201  in Embodiment 1, the first temperature-measuring energization unit  43  for causing a current to flow through the closing drive coil  31 ; wherein the first temperature-correction indication unit  300  includes a closing-drive-coil temperature measuring means that determines the resistance value of the closing drive coil  31  by detecting a value of the voltage produced due to the current flowing through the closing drive coil  31  caused by the first temperature-measuring energization unit  43 , followed by measuring the temperature of the closing drive coil  31  through calculation from the determined resistance value; and wherein the first temperature-correction indication unit  300  indicates to the closing charging circuit  11 , the charge voltage correction value for the closing drive capacitor  21 , on the basis of the temperatures measured by the closing-drive-coil temperature measuring means and the second temperature sensor  202 . 
     Thus, according to this embodiment, it becomes possible to determine the temperature of the closing drive coil  31  without using the first temperature sensor  201  for measuring the temperature of the closing drive coil  31 . 
     Further, an electromagnetic operation device according to this embodiment includes, instead of the third temperature sensor  203  in Embodiment 1, the second temperature-measuring energization unit  44  for causing a current to flow through the opening drive coil  32 ; wherein the second temperature-correction indication unit  400  includes an opening-drive-coil temperature measuring means that determines the resistance value of the opening drive coil  32  by detecting a value of the voltage produced due to the current flowing through the opening drive coil caused by the second temperature-measuring energization unit  44 , followed by measuring the temperature of the opening drive coil  32  through calculation from the determined resistance value; and wherein the second temperature-correction indication unit  400  indicates to the opening charging circuit  12 , the charge voltage correction value for the opening drive capacitor  12 , on the basis of the temperatures measured by the opening-drive-coil temperature measuring means and the fourth temperature sensor  204 . 
     Thus, according to this embodiment, it becomes possible to determine the temperature of the opening drive coil  32  without using the third temperature sensor  203  for measuring the temperature of the opening drive coil  32 . 
     Further, an electromagnetic operation device according to this embodiment includes, instead of the first temperature sensor  201 , the first temperature-measuring energization unit  43  for causing a current to flow through the closing drive coil  31 , wherein the first temperature-correction indication unit  300  indicates to the closing charging circuit  11 , the charge voltage correction value for the closing drive capacitor  21 , on the basis of the temperatures measured by the closing-drive-coil temperature measuring means and the second temperature sensor  202 , said electromagnetic operation device further including, instead of the third temperature sensor  203 , the second temperature-measuring energization unit  44  for causing a current to flow through the opening drive coil  32 , wherein the second temperature-correction indication unit  400  indicates to the opening charging circuit  12 , the charge voltage correction value for the opening drive capacitor  22 , on the basis of the temperatures measured by the opening-drive-coil temperature measuring means and the fourth temperature sensor  204 . 
     Thus, according to this embodiment, it becomes possible to determine the temperature of the closing drive coil  31  without using the first temperature sensor  201  for measuring the temperature of the closing drive coil  31 , and also to determine the temperature of the opening drive coil  32  without using the third temperature sensor  203  for measuring the temperature of the opening drive coil  32 . 
     INDUSTRIAL APPLICABILITY 
     This invention is useful for actualizing an electromagnetic operation device for a vacuum circuit breaker which can suppress a change in closing operation speed or opening operation speed even if the temperature surrounding the drive coil or the drive capacitor changes, thereby making it possible to fulfill the operational duty of making close/open for three cycles (50 msec) defined in the standard (JEC-2300). 
     DESCRIPTION OF REFERENCE NUMERALS AND SIGNS 
       10 : power supply,  11 : closing charging circuit,  12 : opening charging circuit,  21 : closing drive capacitor,  22 : opening drive capacitor,  31 : closing drive coil,  32 : opening drive coil,  41 : first energization unit,  42 : second energization unit,  43 : first temperature-measuring energization unit,  44 : second temperature-measuring energization unit,  201 : first temperature sensor,  202 : second temperature sensor,  203 : third temperature sensor,  204 : fourth temperature sensor,  300 : first temperature-correction indication unit,  400 : second temperature-correction indication unit.