JP2009039678A - Centrifuge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a centrifuge realizing the duplexing of a means for reducing a leak current and a means for preventing electric shock by a relatively simple constitution without using a high-cost insulated transformer or using a motor of a double or reinforced insulation structure and to provide a centrifuge realizing further cost reduction and vampire energy reduction by using a two or fewer circuit switch as the power shut-off switch inserted into the power supply line of a motor driving electric source. <P>SOLUTION: The duplexing of an electric shock prevention means is realized by electrically connecting a switch 7 making electrical continuity or discontinuity to a line L supplying a power to the power conversion circuit (inverter) 15d of a motor driving circuit 15 to control it so that the switch 7 may make electrical discontinuity when a door 3 is open. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a structure for ensuring electrical safety of a centrifuge.

  A centrifuge stores a rotor in which a sample to be separated is held through a tube or bottle in a rotor chamber (rotating chamber), and drives a motor or the like with the opening of the rotor chamber sealed by a door. By rotating the rotor at a high speed with an apparatus, the sample held in the rotor is separated, purified, and the like. The rotational speed of the rotor varies depending on the application, and it has a wide range of rotational speeds, from a relatively low speed with a maximum speed of several thousand revolutions (rpm) to a high speed with a maximum speed of about 150,000 revolutions (rpm). Product groups are generally available.

  A block diagram of a known centrifuge is shown in FIG. The centrifuge includes a motor housing 5a that is a housing of a motor 5 that is a rotational drive source, an output rotation shaft (shaft) 5b of the motor 5, and a rotor 1 that is fixed to the output rotation shaft 5b and holds a sample to be separated. A rotor chamber 2 that accommodates the rotor 1 and has an opening 2a on the upper surface, a door 3 that can be opened and closed in the opening 2a of the rotor chamber 2, and a door lock mechanism 4 that restricts the opening and closing of the door 3. A door opening / closing detector 12 for detecting the opening / closing of the door, a motor driving circuit 15 for driving the motor 5, and a control circuit device 60 for inputting a signal from the door opening / closing detector 12 to control the motor driving circuit 15. The motor 5, the rotor chamber 2, the door lock mechanism 4, the motor drive circuit 15, and the control circuit device 60 are housed in a housing (frame) 10.

  In such a centrifuge, when the door 3 of the rotor chamber 2 is opened, the user may contact the rotating shaft 5b of the motor 5 or the rotor 1 that is electrically connected to the rotating shaft 5b. For this reason, generally an electric insulating layer is provided between the winding of the motor 5 and the rotating shaft 5b to prevent electric shock.

  Furthermore, in order to prevent voltage generation at the rotating shaft 5b even if such an insulating layer breaks down, as shown in FIG. 9, the housing 5a of the motor 5 electrically connected to the shaft 5b is electrically connected. The electric shock prevention means is duplicated by connecting to the ground. Usually, since the centrifuge housing 10 is grounded to the ground E by the ground connection wire 9, the ground connection wire 8 of the motor housing 5a is connected to the centrifuge housing 10 located near the motor housing 5a. Some electrical connections are made. In addition, the leakage current of the centrifuge is equal to or less than a predetermined leakage current that does not have a significant influence on the human body (for example, 3 It is obliged to install a plurality of means for preventing electric shock for centrifuge members that are limited to .5 mA or less) and that may be contacted by the user. In the case where insulation is used as an electric shock prevention means, it is also defined that the insulation portion has a high withstand voltage (for example, 1300 V or more).

  However, depending on the structure of the motor 5 or the circuit configuration of the motor drive circuit 15, it may be difficult to reduce the above-described leakage current within a limit value. In this case, the insulating transformer 13 is used as a general and reliable means for reducing leakage current, as shown in FIG. Alternatively, in the case where the ground connection line 8 (see FIG. 9) is a path for leakage current, the ground 5 is removed as a means for further ensuring safety after the ground connection line 8 is deleted. In some cases, double insulation or reinforced insulation may be performed on the wire with an insulating layer.

  In addition, regarding the above prior art, a technique for preventing electric shock by applying an electrical insulating layer between the rotor winding and the rotating shaft of the motor, or a so-called double insulation in which the motor casing is also made of an insulator. This technique is disclosed in Patent Document 1 below. Further, a technique for preventing leakage current by an insulating transformer is disclosed in Patent Document 2 below.

  Further, in the centrifuge, a technique for ensuring safety when a user touches the rotor or the like by configuring the centrifuge rotor attached to the rotating shaft of the motor with an insulator is shown in Patent Document 3 below. Has been.

  Further, in Patent Document 4, in a centrifuge, a switching device is inserted in a line of a motor drive power supply system between a control circuit device including a motor drive circuit electrically connected to a commercial AC power supply and a motor winding. However, a technique for ensuring safety by disabling the switchgear by the control circuit device when the user can swing to the rotor or the like when the user opens the rotor chamber door of the centrifuge is disclosed. Yes.

Japanese Utility Model Publication No. 60-20753 JP-A-9-187428 Japanese Patent Laid-Open No. 2001-87777 JP 2006-198564 A

  However, the structure using the above-described insulating transformer 13 and the structure in which the motor 5 is double-insulated or reinforced-insulated has a problem of increasing the cost. Moreover, in the technique described in Patent Document 3, there is a restriction that the processing material of the rotor is an insulator, and it is difficult to combine a commonly used metal material rotor with the centrifuge body.

  Further, although Patent Document 4 discloses a technical idea of inserting a switchgear in a motor drive power supply line, a specific example using a three-phase induction motor as a drive motor is described in the motor winding. Only an example in which three switching devices are used in the drive output circuit is disclosed. The technology that uses three such switchgears in the drive output circuit has the disadvantage that standby power consumption cannot be reduced because the power conversion circuit of the motor drive circuit or its control circuit is maintained energized. It was.

  Therefore, the object of the present invention is to reduce leakage current and prevent electric shock by a relatively simple structure without using the above-described high-cost insulation transformer, double insulation structure of motor or reinforced insulation structure. An object of the present invention is to provide a centrifuge that is duplexed.

  Another object of the present invention is to provide a centrifuge that further reduces costs and reduces standby power by using two or fewer power-off switchgears to be inserted into the power supply line of the motor drive power supply system. There is to do.

  The inventor of the present application focused on the following characteristics of the centrifuge and constructed the invention. In other words, the centrifuge is usually configured to lock the door of the rotor chamber and prevent the door from being opened during operation, in order to ensure safety against an unexpected mechanical breakage during operation. Therefore, since the user of the centrifuge cannot contact the rotating shaft or rotor of the motor during operation due to the door being closed, electric shock due to contact with the motor or rotor can be prevented. As a result, an electric shock prevention means is provided in the motor housing during operation. On the other hand, when the centrifuge is stopped, the user can open the door and contact the rotor, etc., so that the motor housing does not have double insulation or reinforced insulation structure to ensure electrical safety In this case, ground connection is required. However, since it is not necessary to rotate the motor during the stop, it is possible to provide an electric shock prevention means by disconnecting the motor drive circuit from the power source. Therefore, in both cases of operation and stop, a plurality of means for preventing electric shock can be realized together with the insulating structure provided between the winding of the motor and the rotating shaft. Furthermore, when disconnecting the power supply of the motor drive circuit, it was considered that the standby power of the motor drive circuit could be reduced by disconnecting the circuit portion closer to the commercial power supply than the power conversion circuit of the motor drive circuit. Of the inventions disclosed in the present application, the outline of typical ones will be described as follows.

  According to one aspect of the present invention, a motor having an output rotating shaft and a motor winding for applying a rotational driving force to the output rotating shaft, a rotor connected to the output rotating shaft and holding a sample to be separated; A rotor chamber containing the rotor and having an opening on the upper surface; a door provided openably and closably to open or close the opening of the rotor chamber; and restricting the opening and closing of the door A door lock mechanism; a motor drive circuit that has a power conversion circuit and supplies drive power to the motor winding; a control circuit device that controls the door lock mechanism and the motor drive circuit; the rotor chamber; the door A centrifuge that houses a lock mechanism, the motor drive circuit, and the control circuit device, and a housing that mounts the door corresponding to the opening of the rotor chamber. A switching device that is electrically connected to the power supply line to the power conversion circuit of the dynamic circuit and that is electrically conductive or non-conductive, and the control circuit device is configured such that the door lock mechanism locks the door. If not, the switchgear is controlled to be non-conductive.

  According to another aspect of the present invention, a motor having an output rotating shaft and a motor winding for applying a rotational driving force to the output rotating shaft, a rotor connected to the output rotating shaft and holding a sample to be separated; A rotor chamber containing the rotor and having an opening on the upper surface; a door provided openably and closably to open or close the opening of the rotor chamber; and detecting opening and closing of the door A door opening / closing detector, a motor driving circuit having a power conversion circuit and supplying driving power to the motor winding, and a control circuit device for controlling the motor driving circuit based on a detection signal of the door opening / closing detector; A housing that houses the rotor chamber, the door open / close detector, the motor drive circuit, and the control circuit device, and that mounts the door corresponding to the opening of the rotor chamber. Smell And an opening / closing device that is electrically connected in the power supply line to the power conversion circuit of the motor driving circuit and that is electrically conductive or non-conductive, and the control circuit device has the door opened. The switchgear is controlled so as to be non-conductive.

  According to still another aspect of the present invention, the motor drive circuit includes a converter that is electrically connected to the power supply line to the power conversion circuit and converts an AC power supply line to a DC power supply line. The switchgear is electrically connected in the AC power supply line or the DC power supply line.

  According to still another aspect of the present invention, the converter includes a rectifier circuit and a smoothing circuit, and the DC power supply line includes a supply line that electrically connects a rectified output of the rectifier circuit to the smoothing circuit, The switchgear is electrically connected in the supply line between the rectifier circuit and the smoothing circuit.

  According to still another aspect of the present invention, the power conversion circuit includes an inverter that converts direct current to alternating current and supplies the motor winding as a drive power source.

  According to still another aspect of the present invention, the switchgear is electrically connected in the DC power supply line that electrically connects the converter to the inverter.

  According to still another aspect of the present invention, the motor drive circuit further includes an inverter drive circuit for switching the inverter, and the drive power supply of the inverter drive circuit is supplied from the DC power supply line of the converter. When supplied and the switchgear becomes non-conductive, the supply from the DC power supply line is stopped.

  According to still another aspect of the present invention, the switchgear is electrically connected in the AC power supply line that supplies AC power to the converter.

  According to still another aspect of the present invention, the motor winding of the motor is constituted by a three-phase connection, and the inverter supplies three-phase AC power to the motor winding.

  According to still another aspect of the present invention, the motor is a three-phase induction motor.

  According to still another aspect of the present invention, the control circuit device controls the switching device to be non-conductive when the motor driving circuit is not controlled.

  According to still another aspect of the present invention, the switchgear is an electromagnetic switch.

  According to still another aspect of the present invention, the motor includes a motor housing, and the motor housing is electrically separated from the housing and housed in the housing.

  According to still another aspect of the present invention, the rotor is formed of a metal material.

  According to the configuration of the present invention described above, since the electrically conductive or non-conductive switchgear is inserted into the power supply line to the motor drive circuit, the number of switchgears to be connected is reduced or the structure thereof is reduced. It can be simple. As a result, it is possible to reduce the cost by reducing the number of power shut-off switching devices to be inserted into the power supply line to two or less, and to reduce the standby power of the motor drive circuit.

  According to the configuration of the present invention described above, the electrically opened / closed switchgear is electrically connected in the power supply line to the motor drive circuit, the centrifuge door is opened, and the user can rotate the rotor. When the switch is in contact with the motor rotating shaft, the switchgear is made non-conductive, so that the electric shock preventing means can be doubled together with the motor insulation. Accordingly, it is possible to provide a centrifugal separator with a simple configuration and low cost, which does not require the addition of an insulation transformer and the double insulation or reinforced insulation of the motor as in the prior art. On the other hand, when the motor is operated, the switchgear is turned on, but the centrifuge door is closed and the door is locked so that the user cannot contact the rotor or the motor rotating shaft. It is possible to double the electric shock prevention means.

  In addition, according to the configuration of the present invention, an electromagnetic switch can be used as the switchgear. Therefore, when the electromagnetic switch is non-conductive, a high withstand voltage (between the switch terminals required as an electric shock prevention means ( For example, 1300 V or more) can be easily obtained. In addition, the stray capacitance between the open and close terminals can be reduced compared to switch devices using electronic switches such as transistors, so leakage current that occurs when the user touches the rotating rotor or motor rotating shaft that is stopped. It is also easy to suppress the value to a value determined by the safety standard of JIS or IEC.

  The above and other objects of the present invention, and the above and other novel features of the present invention will become more apparent from the following description of the present specification and the accompanying drawings.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof will be omitted. Also, members having the same functions as those of the background art are given the same reference numerals as those of the background art.

  1 and 2 are block diagrams of a centrifuge according to an embodiment of the present invention. In particular, FIG. 1 shows that the switchgear 7 is in a non-conductive state, the motor 5 is stopped, and the rotor 1 rotates. FIG. 2 shows a state diagram when the switching device 7 is in a conducting state, the motor 5 rotates, and the rotor 1 rotates. FIG. 3 shows a first embodiment of a principal part circuit diagram in the configuration diagram shown in FIG.

  The centrifuge 100 includes a housing (frame) 10 and has a motor 5 as a rotational drive source assembled and housed therein. The motor 5 includes a metal housing 5a, an output rotating shaft 5b made of a metal material protruding from the motor housing 5a, and a motor housing 5a for applying a rotational driving force to the output rotating shaft 5b. And a built-in motor winding (field winding) 5c.

  Further, the centrifuge 100 accommodates the rotor 1 made of a metal material (for example, aluminum alloy) that is fixed to the output rotating shaft 5b of the motor 5 and holds the sample to be centrifuged, and the opening 2a on the upper surface. , A door 3 provided in an opening 2 a of the rotor chamber 2 formed in the housing 10, a door lock mechanism 4 for restricting the opening and closing of the door 3, and opening and closing of the door 3 Is electrically connected to a power supply line L (including L1 to L4 in FIG. 3) from the commercial AC power supply 11 to the motor drive circuit 15. And a control circuit device 61 that controls the opening and closing device 7, the motor drive circuit 15, the door lock mechanism 4, and the opening and closing device 7. In the present invention, a ground connection line (corresponding to the connection line 8 in FIG. 9) for electrically connecting the motor housing 5a to the housing 10 is not necessary.

  The motor drive circuit 15 includes a power conversion circuit 15 d that converts an output voltage or a power supply frequency of the input AC power supply (commercial power supply) 11. In the present embodiment, as will be described later, the power conversion circuit 15d includes an inverter 15d to which a DC power is input by a converter 15c.

  As shown in FIG. 3, the motor 5 is constituted by, for example, a three-phase induction motor in which the motor winding 5c has a star connection or a delta connection and is supplied with three-phase AC power. The present invention is particularly effective when a multiphase motor is applied as the motor 5.

  In FIG. 3, the motor 5 is composed of a three-phase induction motor that is activated by a 300V three-phase AC power source, and is disposed between the winding 5c of the motor 5 and an iron core (not shown) or on the outer peripheral surface of the rotating shaft 5b. An insulating layer is formed. Although not shown, the motor winding 5c is formed of a well-known star connection, and three-phase AC power generated by the motor drive circuit 15 is supplied to the three input sides of the motor winding 5c.

  The motor drive circuit 15 includes a rectifier circuit 15a including four rectifier diodes Di bridged to an input AC power source (commercial power source) 11 and a smoothing circuit 15b, and a DC output of the converter 15c in three phases. And an inverter (power conversion circuit) 15d for converting to an AC output.

  Converter 15c converts AC power supply lines L1 and L2 into DC power supply lines L3 and L4. That is, the AC power supply 11 supplied to the AC power supply lines L1 and L2 of the converter 15c is composed of, for example, a commercial AC power supply 100V or 200V (50/60 Hz). The power supply 11 is converted into direct current, and direct current power is supplied to the inverter 15d via the direct current power supply lines L3 and L4. Here, the DC power supply lines L3 and L4 also include a supply line that supplies the rectified output of the rectifier circuit 15a that forms the converter 15c to the smoothing circuit 15b. As shown in the embodiment, the switchgear 7 may be electrically connected in the DC power supply lines L3 and L4.

  The inverter 15d converts the DC output voltage of the converter 15c into, for example, a three-phase AC power supply 300V (5 Hz to 2.6 kHz), and supplies three-phase AC power to the three-phase motor winding 5c. The inverter 15d includes six switching elements Tr such as bipolar transistors or IGBTs (insulated gate bipolar transistors) connected in a three-phase bridge format. The collector or emitter of each switching element Tr is connected to the three-phase winding of the star-connected motor winding, and its base or gate is connected to the inverter drive circuit 15f. As a result, the six switching elements Tr perform a switching operation by the switching element drive signal input from the inverter drive circuit 15f, and the output DC voltage of the converter 15c applied to the inverter 15d is set as a three-phase drive voltage. Electric power is supplied to the motor winding (armature winding) 5c. A known technique can be applied to the inverter 15d. The inverter drive circuit 15 f is controlled by the control circuit device 61.

  The inverter drive circuit (interface circuit) 15f is composed of a switching element such as a bipolar transistor, and outputs a drive signal to drive the inverter 15d. According to one embodiment shown in FIG. 3, the DC voltage for driving the switching element of the inverter drive circuit 15f is a DC power supply circuit that converts the AC power supply 11 configured in the inverter drive circuit 15f into DC by a rectifier circuit. (Not shown). According to one embodiment shown in FIG. 3, the AC power supply 11 supplied to the DC power supply circuit is branched from the output side of the switchgear 7 (the input side of the rectifier circuit 15a). As a result, when the switching device 7 becomes non-conductive, drive power is not supplied to the inverter drive circuit 15f, so that standby power consumption of the inverter drive circuit 15f when the motor drive circuit 15 is in a stopped state is prevented. Can do. Further, the drive power supply circuit (DC power supply circuit) of the inverter drive circuit 15f may use the DC voltage branched from the output side of the converter 15c as in another embodiment shown in FIG.

  Although not illustrated, the control circuit device 61 temporarily stores a CPU for outputting a drive signal of the inverter drive circuit 15f based on the processing program and data, a ROM for storing the processing program and control data, and data. Including a microcomputer including a RAM, a timer, and the like.

  The switchgear 7 conducts (connects) or does not conduct the power supply line L that supplies the AC power supply 11 to the power converter 15d of the motor drive circuit 15 in accordance with a control signal applied from the control circuit device 61 to the control terminal CL. Control to (block). In a preferred embodiment, the switchgear 7 is constituted by an electromagnetic switch (electromagnetic relay). The example shown in FIG. 3 is a case where a dual-type (two-contact type) electromagnetic switch 7 is used. The power supply lines L1 and L2 of the drive power supply (AC power supply) 11 are connected to the two contacts S1 and S2 of the electromagnetic switch 7 serving as a switching device, and power is supplied to the power converter 15d via the contacts S1 and S2. Is done. Control of conduction (connection) or non-conduction (cutoff) of each switch S1, S2 of the electromagnetic switch 7 is controlled by a control signal of the control circuit device 61 applied to the control terminal CL.

  Second and third embodiments using an electromagnetic switch as the switchgear 7 are shown in FIGS. 4 and 5, respectively. The electromagnetic switch 7 in the second embodiment of FIG. 4 is an example using two one-contact type (S1, S2), and can be configured in the same manner as in FIG. Further, since a general commercial power supply facility is a neutral line N with one of the lines grounded, when the neutral line N can be specified, as shown in the third embodiment of FIG. It can be composed of a single contact type (S1) switchgear 7.

  Further, as shown in the fourth and fifth embodiments of FIGS. 6 and 7, the switchgear 7 is connected to DC power supply lines L3 and L4 (including rectification or pulsating power supply lines) forming the converter 15c. An electrical connection may be made. 6 and 7, the switchgear 7 is connected to the DC power supply lines L3, L4, and the drive power supply of the inverter drive circuit 15f is branched from the power supply lines L3, L4 via the switchgear 7. The so-called DC power supply input type configuration is provided. This is different from the AC power supply input type configuration in which the drive power supply of the inverter drive circuit 15f is branched and supplied from the AC power supply lines L1 and L2 of the embodiment shown in FIGS.

  In the embodiment shown in FIG. 6, the same electric shock prevention effect as that of the embodiment shown in FIG. 3 can be obtained. Moreover, since the drive power supply of the inverter drive circuit 15f is also cut off by the switchgear 7, the standby power can be reduced. In this case, the standby power of the rectifier circuit 15a of the converter 15c is sufficiently smaller than that of other circuits, so that the power consumption is not a problem.

  Also in the embodiment shown in FIG. 7, the same electric shock prevention effect as that of the embodiment shown in FIG. 6 can be obtained. Similarly, standby power when the switching device 7 is shut off can be reduced. In this case, the advantage of the embodiment of FIG. 6 is that the smoothing circuit 15b remains energized, so that the waiting time until the voltage required for operation (for example, 300V) is reached when the switchgear 7 is turned on ( For example, 0.5 to 1.0 seconds) becomes unnecessary. This can avoid the inconvenience that the acceleration time of the rotor is delayed. This embodiment is advantageous when applied to a centrifuge that needs to be accelerated in a short time.

  Next, the operation of the centrifuge 100 according to the present embodiment will be described.

  As shown in FIG. 2, the switchgear (electromagnetic switch) 7 is controlled to be in a conductive state by the control circuit device 61 when the door 3 is closed at the stage of operation of the centrifuge. When the door 3 is closed and the door opening / closing detector 12 detects the closed state of the door 3, or when the door is closed and the door is locked by the door lock mechanism 4, the electromagnetic opening and closing shown in the embodiment of FIG. Each contact S1, S2 of the container 7 is in a conductive state (connected state). Thereafter, the motor drive circuit 15 supplies a high three-phase AC power supply voltage (for example, 300 V) to the motor winding 5 c to rotate the motor 5. That is, the AC power supply 11 is frequency-converted via the motor drive circuit 15 and supplied to the winding 5 c of the motor 5. Accordingly, during the operation of the motor 5, only a single insulation provided to the motor 5 is provided between the AC power source 11, the rotor 1 and the motor housing 5a. Since 3 is closed and locked, the user of the centrifuge 100 cannot touch the motor housing 5a, the rotating shaft 5b of the motor 5, or the rotor 1, so that the second electric shock prevention means is installed. become.

  On the other hand, as shown in FIG. 1, when the operation of the centrifuge 100 is stopped and the door 3 is opened, for example, after the operation of the motor 5 is stopped, the control circuit device 61 releases the door lock mechanism 4, When the user opens the door 3, the control circuit device 61 receives the unlock signal of the door lock mechanism 4 or the open signal of the door open / close detector 12, and outputs a control signal to the control terminal CL, as shown in FIG. The electrical connection with the drive power supply with respect to the coil | winding 5c of the motor 5a is interrupted | blocked by making each contact S1, S2 of the switchgear (electromagnetic switch) 7 shown into a non-passage (shut off). When the door 3 is opened, the user may come into contact with the rotating shaft 5b of the motor 5 or the rotor 1 that is electrically connected to the rotating shaft 5b. Since the electrical connection with the drive power supply (AC power supply) to the motor winding 5c is interrupted by the device 7, the opening / closing device 7 functions as a second electric shock prevention means when the door 3 is opened. At this time, the rectifier circuit 15a, the smoothing circuit 15b, the inverter 15d, and the inverter drive circuit 15f are not supplied with power from the AC power supply 11 because the switchgear 7 is turned off, so that standby power is generated. Disappear.

  The advantage of using an electromagnetic switch as the switchgear 7 inserted according to the present invention is that the withstand voltage at both ends of the switchgear 7 when opened can be set to 1300 V or more, and when the switchgear 7 is shut off. The stray capacitance (stray capacitance Cs) between both ends (when non-conducting) can be reduced. In particular, when an electromagnetic switch is used, it is advantageous when performing a high withstand voltage test of a centrifuge, and since an electromagnetic switch has a small floating capacity Cs when cut off, it is used for a rotor or a rotating shaft of a rotor. It is also advantageous in that the leakage current generated when a person contacts can be reduced. When the switch device 7 may have a relatively low withstand voltage, an electronic switch including a semiconductor switch such as a transistor may be used in addition to the electromagnetic switch.

  The control of the opening / closing device 7 by the control circuit device 61 may be executed when the door opening / closing detector 12 detects the opening / closing of the door 3, or when the door lock mechanism 4 detects the door lock or release thereof. You may do it. In addition, when the control circuit device 61 is not driving the motor 5, the opening / closing device 7 may be controlled to be non-conductive.

  As shown in FIG. 2, when the centrifuge is used in an environment having a grounding facility, the casing 10 of the centrifuge body may be connected to the ground E via the ground connection line 9.

  As will be apparent from the above description of the embodiment, according to the present invention, the switchgear is inserted into the power supply line of the motor drive circuit, and the open / closed control of the motor is controlled by the motor drive control circuit device. The electric shock prevention means can be duplicated by controlling by.

  In this case, consumption of standby power when the motor operation is stopped can be reduced, and a relatively simple switchgear can be applied. Further, the motor ground connection line 8 in the prior art as shown in FIG. 9 can be eliminated, and the leakage current can be reduced. As a result, the motor core or rotating shaft does not use a double insulation structure or a reinforced insulation structure, and is not restricted by the shape and material of the centrifuge rotor and the structure of the switchgear. The intended purpose can be achieved by the configuration.

  As mentioned above, although the invention made | formed by this inventor was demonstrated based on embodiment, this invention is not limited to the said embodiment, A various change is possible within the range which does not deviate from the summary. In the above embodiment, a three-phase motor is used as the motor, but other motors such as a two-phase motor may be applied in addition to the three-phase motor. Also, a PWM modulated (pulse width modulated) signal may be used as the drive signal for the inverter drive circuit. Furthermore, a power transformer may be used on the input side of the power conversion circuit to transform the input AC power source.

The block diagram of the centrifuge which concerns on embodiment of this invention. The block diagram which shows the state which obstruct | occluded the door in the centrifuge of this invention shown in FIG. The principal part block diagram according to 1st Example in the centrifuge of this invention shown in FIG. The principal part block diagram according to 2nd Example in the centrifuge of this invention shown in FIG. The principal part block diagram according to the 3rd Example in the centrifuge of this invention shown in FIG. The principal part block diagram according to the 4th Example in the centrifuge of this invention shown in FIG. The principal part block diagram according to the 5th Example in the centrifuge of this invention shown in FIG. The block diagram of the centrifuge which shows an example of a prior art. The block diagram of the centrifuge which shows the other example of a prior art.

Explanation of symbols

1: Rotor 2: Rotor chamber 2a: Opening of rotor chamber 3: Door 4: Door lock mechanism 5: Motor 5a: Motor housing (motor housing)
5b: Output rotating shaft (shaft) 5c: Motor winding (three-phase field winding)
7: Switchgear 8: Motor ground connection line 9: Chassis ground connection line 10: Centrifuge housing 11: AC power supply (commercial AC power supply)
12: Door open / close detector 13: Insulation transformer 15: Motor drive circuit 15a: Rectifier circuit 15b: Smoothing circuit 15c: Converter 15d: Power conversion circuit (inverter) 15f: Inverter drive circuit 60: Control circuit device (conventional) 61: Control Circuit device (present invention)
100: Centrifuge E: Earth L, L1, L2, L3, L4: Power supply line N: Neutral wire S, S1, S2: Electromagnetic switch contact

Claims (14)

A motor having an output rotating shaft and a motor winding for applying a rotational driving force to the output rotating shaft, a rotor connected to the output rotating shaft and holding a sample to be separated, and housing the rotor, opening on the upper surface A rotor chamber having a section, a door that can be opened and closed in the opening to open or close the opening of the rotor chamber, a door lock mechanism that restricts the opening and closing of the door, and a power conversion circuit. A motor drive circuit that supplies drive power to the motor winding, a control circuit device that controls the door lock mechanism and the motor drive circuit, the rotor chamber, the door lock mechanism, the motor drive circuit, and the In a centrifuge having a housing that houses a control circuit device and that mounts the door corresponding to the opening of the rotor chamber,
The motor drive circuit further includes an opening / closing device that is electrically connected in the power supply line to the power conversion circuit and electrically conductive or non-conductive, and the control circuit device includes the door lock mechanism that includes the door. The centrifuge is controlled so that the switchgear is turned off when the switch is not locked. A motor having an output rotating shaft and a motor winding for applying a rotational driving force to the output rotating shaft, a rotor connected to the output rotating shaft and holding a sample to be separated, and housing the rotor, opening on the upper surface A rotor chamber having a portion, a door that is openable and closable to open or close the opening of the rotor chamber, a door open / close detector that detects opening and closing of the door, and a power conversion circuit A motor drive circuit for supplying drive power to the motor winding, a control circuit device for controlling the motor drive circuit based on a detection signal of the door open / close detector, the rotor chamber, and the door open / close detector A centrifuge having a housing for housing the motor drive circuit and the control circuit device and mounting the door corresponding to the opening of the rotor chamber.
The motor drive circuit further includes an opening / closing device that is electrically connected in the power supply line to the power conversion circuit and electrically conductive or non-conductive, and the control circuit device has the door open. Then, the centrifuge is controlled so that the switchgear is turned off.   The motor drive circuit includes a converter that is electrically connected to the power supply line to the power conversion circuit and converts an AC power supply line to a DC power supply line, and the switchgear is in the AC power supply line. Alternatively, the centrifugal separator according to claim 1 or 2, wherein the centrifugal separator is electrically connected in the DC power supply line.   The converter includes a rectifier circuit and a smoothing circuit, the DC power supply line includes a supply line that electrically connects a rectified output of the rectifier circuit to the smoothing circuit, and the switchgear includes the rectifier circuit, the smoothing circuit, and the smoothing circuit. The centrifuge according to claim 3, wherein the centrifuge is electrically connected in the supply line between the two.   5. The centrifugal separator according to claim 1, wherein the power conversion circuit includes an inverter that converts direct current into alternating current and supplies the motor windings as drive power. 6.   6. The centrifugal separator according to claim 5, wherein the switchgear is electrically connected in the DC power supply line that electrically connects the converter to the inverter.   The motor drive circuit further includes an inverter drive circuit for switching the inverter, and drive power for the inverter drive circuit is supplied from the DC power supply line of the converter, and the switchgear is turned off. The centrifuge according to claim 6, wherein the supply from the DC power supply line is stopped.   6. The centrifugal separator according to claim 5, wherein the switchgear is electrically connected in the AC power supply line that supplies AC power to the converter.   The centrifugal motor according to any one of claims 5 to 8, wherein the motor winding of the motor is constituted by a three-phase connection, and the inverter supplies three-phase AC power to the motor winding. Separator.   The centrifuge according to claim 9, wherein the motor is a three-phase induction motor.   The centrifugal separator according to any one of claims 1 to 10, wherein the control circuit device controls the switching device to be non-conductive when the motor driving circuit is not controlled. Machine.   The centrifuge according to any one of claims 1 to 11, wherein the switchgear is an electromagnetic switch.   13. The motor according to claim 1, wherein the motor includes a motor housing, and the motor housing is electrically separated from the housing and housed in the housing. Centrifuge.   The centrifuge according to any one of claims 1 to 13, wherein the rotor is made of a metal material.

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