JPH0480614B2 - - Google Patents
Info
- Publication number
- JPH0480614B2 JPH0480614B2 JP60052536A JP5253685A JPH0480614B2 JP H0480614 B2 JPH0480614 B2 JP H0480614B2 JP 60052536 A JP60052536 A JP 60052536A JP 5253685 A JP5253685 A JP 5253685A JP H0480614 B2 JPH0480614 B2 JP H0480614B2
- Authority
- JP
- Japan
- Prior art keywords
- current transformer
- resistor
- changeover switch
- secondary winding
- motor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000004804 winding Methods 0.000 claims description 46
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000001012 protector Effects 0.000 description 1
Landscapes
- Protection Of Generators And Motors (AREA)
Description
（技術分野）
本発明は、電動機に過負荷が作用したときに前
記電動機への電力供給用の電路を開いて前記電動
機を保護する過負荷保護装置に関する。
（従来技術）
電動機の焼損を防止するための過負荷保護装置
の１つとして、前記電動機への電力供給用の電路
に組み入れられる開閉部および該開閉部を制御す
る電磁コイルを備えた電磁接触器と、前記電動機
に流れる電流量に応じて発熱する抵抗体および該
抵抗体の温度に応じて開閉されるスイツチ部を備
えた熱動継電器とを用い、前記スイツチ部を前記
電磁コイルの電源回路に組み入れた装置がある。
しかし、前記熱動継電器の動作特性、特に定格
電流は、熱動継電器の種類により異なる。このた
め、電磁接触器および熱動継電器を用いた従来の
過負荷保護装置およびこれを組み込んだ電動機用
制御装置は、熱動継電器の定格に応じて決定され
る特定の定格の電動機専用の装置として用いるこ
とができるにすぎない。
過負荷保護装置の他の１つとして、複数のタツ
プを備える変流器を、電動機への電力供給路と前
記電動機に供給される電力に応答する過電流継電
器との間に配置し、前記過電流継電器に接続する
前記タツプを電動機の定格に応じて選択するよう
にした装置がある。しかし、この装置では、電流
計をこれの定格により決定される特定の定格以外
の電動機特に前記定格より大きい定格の電動機の
負荷電流監視用として使用することはできないか
ら、電流計を交換しない限り、定格が異なる各種
の電動機用の装置として使用することができな
い。
（発明の目的）
本発明は、熱動継電器および負荷電流用の電流
計の定格が固定であつても、熱動継電器および電
流計を交換することなく、定格が異なる各種の電
動機用の装置として使用することができる、電動
機の過負荷保護装置を提供することを目的とす
る。
（発明の構成）
本発明の電動機の過負荷保護装置は、電動機へ
電力供給用の電路に組み入れられて該電路を開閉
する開閉部および該開閉部を制御する電磁コイル
を備える電磁接触器と、１次巻線、２次巻線およ
び該１次巻線または２次巻線に接続された複数の
タツプを備える第１の変流器であつて前記１次巻
線が前記電路に直列に接続される第１の変流器
と、該第１の変流器の前記２次巻線に接続される
抵抗体および該抵抗体の温度に応じて開閉される
スイツチ部を備える熱動継電器であつて該スイツ
チ部が前記電磁コイルへ電力を供給する回路に組
み入れられた熱動継電器と、切替端子およびこれ
に選択的に接続される複数の固定端子を備える第
１の切替スイツチであつて前記固定端子が前記タ
ツプに独立的に接続された、前記電路と前記第１
の変流器との間または前記第１の変流器と前記熱
動継電器との間に組み入れられた第１の切替スイ
ツチと、１次巻線および２次巻線を備える第２変
流器であつて該１次巻線が前記抵抗体を経て前記
第１の変流器の前記２次巻線に接続された第２の
変流器と、該第２の変流器の前記２次巻線に接続
された整流回路と、切替端子およびこれと選択的
に接続される複数の固定端子を備える第２の切替
スイツチであつて前記第１の切替スイツチと連動
して切り替えられる第２の切替スイツチと、前記
整流回路の出力電流を検出し表示する電流計と、
前記電動機を定格が異なる他の電動機に変更した
とき、前記電流計に加わる電圧がほぼ一定になる
ように、前記整流回路の負荷抵挺抗を補正するた
めの抵抗器群であつて抵抗値が異なる複数の抵抗
器から成り、各抵抗器の一端が前記第２の切替ス
イツチの固定端子に独立的に接続され、他端が互
いに共通に接続された抵抗器群とを含み、前記第
２の切替スイツチ、前記抵抗器群および前記電流
計は前記整流回路の出力端子に直列に接続されて
いることを特徴とする。
（発明の作用効果）
本発明の過電流保護装置において、第１の変流
器の１次巻線または２次巻線の有効巻線数が第１
の切替スイツチにより変更されると、前記第１の
変流器の２次側の電流量ひいては熱動継電器に流
れる電流量が変更され、同時に整流回路に接続さ
れる抵抗器が第２の切替スイツチにより切替られ
て整流回路の負荷抵抗値が変更される。このた
め、熱動継電器および電流計の定格と異なる定格
の電動機用の過負荷保護装置として使用するとき
は、保護すべき電動機の定格が熱動継電器および
電流計の定格と異なつても、熱動継電器および電
流計にはこれらの定格に応じた電流が流れる。
本発明によれば、熱動継電器および電流計の定
格が固定であるにもかかわらず、熱動継電器およ
び電流計を交換することなしに、定格が異なる電
動機用の装置に転用することができる。
（実施例）
以下、図面に示す実施例について説明する。
第１図に符号１０で示す過負荷保護装置は、３
相交流電源１２に接続された３相交流誘導電動機
１４に用いられる。過負荷保護装置１０は、電磁
接触器１６と、第１および第２の変流器１８，２
０と、第１の変流器１８の１次巻線１８1の有効
巻数を切り替える第１の切替スイツチ２２と、第
１の変流器１８と第２の変流器２０とに接続され
た熱動継電器２４と、第２の変流器２０の２次巻
線２０2に接続された整流回路２６と、複数の抵
抗器２８1〜２８8から成る抵抗器群２８と、整流
回路２６の出力端子に接続する抵抗器群２８の抵
抗器を切り替える第２の切替スイツチ３０と、電
動機１４に流れる負荷電流を監視する電流計３２
とを含む。
電磁接触器１６は、電源１２から電動機１４へ
の電力供給用の電路３４ａ，３４ｂ，３４ｃに組
み入れられた開閉部１６ａ，１６ｂ，１６ｃと、
該開閉部を開閉する電磁コイル１６0とを備える。
電磁コイル１６0は、電路３４ａ，３４ｂに接続
された回路３６に組み入れられて回路３６を電源
回路としている。
第１の変流器１８は、１次巻線１８1、２次巻
線１８2および鉄芯１８3の外に、１次巻線１８1
の途中から引き出された複数のタツプ３８1〜３
８4を備える。また、第２の変流器２０は、１次
巻線２０1、２次巻線２０2および鉄芯２０3を有
する。第１の変流器１８の２次巻線１８2と第２
の変流器２０の１次巻線２０1とは、直列に接続
されている。
第１の切替スイツチ２２は、１つの切替端子２
２0と、これに選択的に接続される複数の固定端
子２２1〜２２8とを備える。固定端子２２1，２
２5はタツプ３８1に、固定端子２２2，２２6タツ
プ３８2に、固定端子3，２２7はタツプ３８3に、
固定端子２２4，２２8はタツプ３８4にそれぞれ
接続されている。
第１の切替スイツチ２２の固定端子２２1〜２
２8は、たとえば、２２1が50Hz用1.5KWの電動
機、２２2が50Hz用2.2KWの電動機、２２3が50Hz
用3.7KWの電動機のように、保護する電動機の
定格出力に対応されている。このため、第２図に
示すように、第１の切替スイツチ２２の操作部４
０には、保護する電動機の定格出力を表示した銘
板４２が設けられている。
第１の変流器１８の１次巻線１８1の一端は、
開閉部１６ｃを経て電源１２に接続され、また第
１の切替スイツチ２２の切替端子２２0は、電動
機１４の入力端子接続されている。このため、第
１の変流器１８の１次巻線１８1と第１の切替ス
イツチ２２とは、電路３４ｃに直列に接続されて
いる。
熱動継電器２４は、複数の抵抗体２４1，２４2
と、該抵抗体の温度に応じて開閉されるスイツチ
部２４0とを備える。各抵抗体２４1，２４2は、
第１の変流器１８の２次巻線１８2と、第２の変
流器２０の１次巻線２０1とに直列に接続されて
おり、スイツチ部２４0は、電磁コイル１６0の電
源回路３６に組み込まれてこれを開閉する。スイ
ツチ部２４0は、常閉接点である。
なお、第４図に示す過負荷保護装置６０のよう
に、第１の切替スイツチ２２は、タツプ３８1〜
３８8を第１の変流器１８の２次巻線１８2から引
き出し、第１の切替スイツチ２２を第１の変流器
１８の２次側に配置してもよい。
整流回路２６は、第２の変流器２０の２次巻線
２０2に並列に接続された分圧用の抵抗４４ａ，
４４ｂと、第２の変流器２０の２次巻線２０2に
直列に接続された整流器４６ａ，４６ｂと、抵抗
４８とを備える。整流器４６ａ，４６ｂは、ダイ
オードであり、負側を互いに接続されている。
抵抗４８は、整流回路２６の負荷抵抗であり、
整流器の負側の共通接続点と第２の切替スイツチ
３０の切替端子３０0との間に直列に接続されて
いる。
抵抗器群２８の各抵抗器２８1〜２８8は、保護
する電動機を変更したときに、電流計３２に加わ
る電圧がほぼ一定になるように、整流回路２６の
負荷抵抗を補正するためのものであり、異なる抵
抗値を有する。
第２の切替スイツチ３０は、切替端子３０0と、
複数の固定端子３０1〜３０8を有する。切替端子
３０0は整流回路２６の抵抗４８に接続されてお
り、固定端子３０1〜３０8は抵抗器２８1〜２８8
に接続されている。
電流計３２の一方の端子は整流回路２６の抵抗
４４ａ，４４ｂの共通接続点に接続されており、
他方の端子は抵抗器群２８の各抵抗器２８1〜２
８8の共通接続点に接続されている。電流計３２
の表示部は、第３図に示すように、指針５０の先
端の軌跡に沿つて記された目盛５２を、電動機が
過負荷の状態であることを示す領域５４と、過負
荷の状態でないことを示す領域５６とに色分けし
ている。領域５６には、電動機を無負荷の状態で
稼動させたときに指針５０が指し示す位置を表わ
す補助の目盛５８が設けられている。
装置１０において、変流器１８の定格を
120A：5A、変流器２０の定格を5A：10mA、抵
抗４４ａ，４４ｂの抵抗値を1.00K〓、抵抗４８
の抵抗値を7K〓とすると、次表に示す仕様の基
に稼動させると好適である。
(Technical Field) The present invention relates to an overload protection device that protects the motor by opening an electric path for supplying power to the motor when an overload is applied to the motor. (Prior Art) As one of the overload protection devices for preventing burnout of an electric motor, an electromagnetic contactor is provided, which is equipped with a switching part that is incorporated into an electric circuit for supplying power to the motor, and an electromagnetic coil that controls the switching part. and a thermal relay including a resistor that generates heat in accordance with the amount of current flowing through the motor and a switch part that opens and closes in accordance with the temperature of the resistor, and the switch part is connected to the power supply circuit of the electromagnetic coil. There is a built-in device. However, the operating characteristics of the thermal relay, particularly the rated current, differ depending on the type of thermal relay. For this reason, conventional overload protection devices using electromagnetic contactors and thermal relays, and motor control devices incorporating them, are designed specifically for motors with a specific rating determined according to the rating of the thermal relay. It can only be used. Another type of overload protection device is to place a current transformer with a plurality of taps between the power supply path to the motor and an overcurrent relay responsive to the power supplied to the motor. There is a device in which the tap connected to the current relay is selected depending on the rating of the motor. However, with this device, the ammeter cannot be used to monitor the load current of a motor with a rating other than the specified rating determined by the ammeter, especially a motor with a rating greater than the above rating, so unless the ammeter is replaced, It cannot be used as a device for various electric motors with different ratings. (Object of the Invention) The present invention provides a device for various electric motors with different ratings without replacing the thermal relay and ammeter, even if the rating of the thermal relay and ammeter for load current is fixed. It is an object of the present invention to provide an overload protection device for an electric motor that can be used. (Structure of the Invention) The overload protection device for an electric motor of the present invention includes an electromagnetic contactor that is incorporated into an electric circuit for supplying power to the electric motor and includes an opening and closing section that opens and closes the electric circuit, and an electromagnetic coil that controls the opening and closing section; A first current transformer comprising a primary winding, a secondary winding, and a plurality of taps connected to the primary winding or the secondary winding, the primary winding being connected in series to the electrical circuit. A thermal relay comprising a first current transformer, a resistor connected to the secondary winding of the first current transformer, and a switch part that opens and closes depending on the temperature of the resistor. a first changeover switch in which the switch portion includes a thermal relay incorporated in a circuit for supplying power to the electromagnetic coil; a changeover terminal; and a plurality of fixed terminals selectively connected to the changeover terminal; the electrical path and the first electrical path, the terminals being independently connected to the taps;
a first changeover switch incorporated between the current transformer or between the first current transformer and the thermal relay, and a second current transformer comprising a primary winding and a secondary winding. a second current transformer, the primary winding of which is connected to the secondary winding of the first current transformer via the resistor; and the secondary winding of the second current transformer. a second changeover switch comprising a rectifier circuit connected to a winding, a changeover terminal and a plurality of fixed terminals selectively connected thereto; a second changeover switch that is switched in conjunction with the first changeover switch; a changeover switch; an ammeter that detects and displays the output current of the rectifier circuit;
A group of resistors with a resistance value for correcting the load resistance of the rectifier circuit so that the voltage applied to the ammeter becomes approximately constant when the motor is changed to another motor with a different rating. a resistor group consisting of a plurality of different resistors, one end of each resistor being independently connected to the fixed terminal of the second changeover switch, and the other end being commonly connected to each other; The changeover switch, the resistor group, and the ammeter are connected in series to the output terminal of the rectifier circuit. (Operation and Effect of the Invention) In the overcurrent protection device of the present invention, the effective number of turns of the primary winding or the secondary winding of the first current transformer is the first
When changed by the changeover switch, the amount of current on the secondary side of the first current transformer and the amount of current flowing through the thermal relay are changed, and at the same time, the resistor connected to the rectifier circuit is changed by the second changeover switch. is switched to change the load resistance value of the rectifier circuit. Therefore, when used as an overload protector for a motor with a rating different from that of a thermal relay or ammeter, even if the rating of the motor to be protected is different from that of the thermal relay or ammeter, Current flows through relays and ammeters according to their ratings. According to the present invention, even though the ratings of the thermal relay and ammeter are fixed, the thermal relay and ammeter can be used for a device for a motor with a different rating without replacing the thermal relay and ammeter. (Example) Hereinafter, an example shown in the drawings will be described. The overload protection device designated by numeral 10 in FIG.
It is used for a three-phase AC induction motor 14 connected to a phase AC power supply 12. The overload protection device 10 includes an electromagnetic contactor 16 and first and second current transformers 18 and 2.
0, a first changeover switch 22 that switches the effective number of turns of the primary winding 181 of the first current transformer 18, and the first current transformer 18 and the second current transformer 20. A thermal relay 24 , a rectifier circuit 26 connected to the secondary winding 20 2 of the second current transformer 20 , a resistor group 28 consisting of a plurality of resistors 28 1 to 28 8 , and a rectifier circuit 26 connected to the secondary winding 20 2 of the second current transformer 20 A second changeover switch 30 that switches the resistors of the resistor group 28 connected to the output terminal, and an ammeter 32 that monitors the load current flowing through the motor 14.
including. The electromagnetic contactor 16 includes opening/closing parts 16a, 16b, and 16c that are incorporated in electrical circuits 34a, 34b, and 34c for supplying power from the power source 12 to the electric motor 14,
It includes an electromagnetic coil 160 that opens and closes the opening/closing section.
The electromagnetic coil 16 0 is incorporated into a circuit 36 connected to the electric lines 34a and 34b, making the circuit 36 a power supply circuit. The first current transformer 18 includes a primary winding 18 1 , a secondary winding 18 2 and an iron core 18 3 .
Multiple taps 38 1 to 3 pulled out from the middle of
8 Prepare for 4 . Further, the second current transformer 20 has a primary winding 20 1 , a secondary winding 20 2 and an iron core 20 3 . The secondary winding 18 2 of the first current transformer 18 and the second
are connected in series with the primary winding 20 1 of the current transformer 20 . The first changeover switch 22 has one changeover terminal 2
2 0 and a plurality of fixed terminals 22 1 to 22 8 selectively connected thereto. Fixed terminal 22 1 , 2
2 5 to tap 38 1 , fixed terminals 22 2 and 22 6 to tap 38 2 , fixed terminals 3 and 22 7 to tap 38 3 ,
Fixed terminals 22 4 and 22 8 are connected to taps 38 4 , respectively. Fixed terminals 22 1 to 2 of the first changeover switch 22
2 8 is, for example, 22 1 is a 1.5KW motor for 50Hz, 22 2 is a 2.2KW motor for 50Hz, and 22 3 is a 50Hz motor.
It corresponds to the rated output of the motor to be protected, such as a 3.7KW motor. Therefore, as shown in FIG.
0 is provided with a nameplate 42 indicating the rated output of the motor to be protected. One end of the primary winding 18 1 of the first current transformer 18 is
It is connected to the power supply 12 via the opening/closing part 16c, and the switching terminal 220 of the first switching switch 22 is connected to the input terminal of the electric motor 14. Therefore, the primary winding 181 of the first current transformer 18 and the first changeover switch 22 are connected in series to the electric line 34c. The thermal relay 24 includes a plurality of resistors 24 1 , 24 2
and a switch section 240 that is opened and closed depending on the temperature of the resistor. Each resistor 24 1 , 24 2 is
The switch portion 24 0 is connected in series to the secondary winding 18 2 of the first current transformer 18 and the primary winding 20 1 of the second current transformer 20 . It is incorporated into the power supply circuit 36 to open and close it. The switch section 240 is a normally closed contact. Note that, like the overload protection device 60 shown in FIG .
38 8 may be drawn from the secondary winding 18 2 of the first current transformer 18 and the first changeover switch 22 may be placed on the secondary side of the first current transformer 18 . The rectifier circuit 26 includes a voltage dividing resistor 44a connected in parallel to the secondary winding 202 of the second current transformer 20,
44b, rectifiers 46a and 46b connected in series to the secondary winding 202 of the second current transformer 20, and a resistor 48. The rectifiers 46a and 46b are diodes whose negative sides are connected to each other. Resistor 48 is a load resistance of rectifier circuit 26,
It is connected in series between the common connection point on the negative side of the rectifier and the switching terminal 30 0 of the second switching switch 30 . Each of the resistors 28 1 to 28 8 in the resistor group 28 is used to correct the load resistance of the rectifier circuit 26 so that the voltage applied to the ammeter 32 becomes approximately constant when the motor to be protected is changed. and have different resistance values. The second changeover switch 30 has a changeover terminal 300 ,
It has a plurality of fixed terminals 30 1 to 30 8 . The switching terminal 300 is connected to the resistor 48 of the rectifier circuit 26, and the fixed terminals 301 to 308 are connected to the resistors 281 to 288.
It is connected to the. One terminal of the ammeter 32 is connected to the common connection point of the resistors 44a and 44b of the rectifier circuit 26,
The other terminal is connected to each resistor 28 1 to 2 of the resistor group 28.
8 Connected to 8 common connection points. Ammeter 32
As shown in FIG. 3, the display unit has a scale 52 marked along the locus of the tip of the pointer 50, and an area 54 indicating that the motor is in an overload condition and an area 54 indicating that the motor is not in an overload condition. The area 56 is color-coded to indicate the area 56. An auxiliary scale 58 is provided in the area 56 to indicate the position indicated by the pointer 50 when the motor is operated under no load. In the device 10, the rating of the current transformer 18 is
120A: 5A, current transformer 20 rating is 5A: 10mA, resistance value of resistors 44a and 44b is 1.00K, resistor 48
Assuming that the resistance value of is 7K, it is suitable to operate based on the specifications shown in the following table.
【表】
電動機１４の動作時、電源１２から電路３４ｃ
を経て電動機１４へ供給される電流は、第１の変
流器１８および第１の切替スイツチ２２を経て流
れる。これにより、第１および第２の変流器１
８，２０の２次巻線１８2，２０2に２次電流が流
れ、熱動継電器２４の抵抗体２４1，２４2は発熱
し、また整流回路２６の出力に整流電圧が得ら
れ、電動機１４に流れる電流を電流計３２により
知ることができる。
電動機１４に流れる電流が熱動継電器２４の定
格電流以下であると、熱動継電器２４のスイツチ
部２４0が閉路の状態を維持することにより、電
磁接触器１６の各開閉部は閉路の状態を維持する
ため、電動機１４は回転を続ける。このとき電流
計３２の指針５０は領域５６を指し示す。
しかし、電動機１４に熱動継電器２４の定格電
流を越える電流が流れると、熱動継電器２４の各
抵抗体２４1，２４2の温度が高くなり、それによ
りスイツチ部２４0が開路するため、電磁接触器
１６の各開閉部１６ａ，１６ｂが開路する。これ
により、電動機１４の過負荷が防止される。この
とき、電流計３２の指針５０は、領域５４を指し
示す。
その後、熱動継電器２４の抵抗体２４1，２４2
の温度が低下すると、スイツチ部２４0が閉じ、
電動機１４への電力の供給が再開される。
装置１０を定格出力が異なる他の電動機に使用
するときは、第１の切替スイツチ２２の切替端子
２２0を前記電動機の定格出力に応じて固定端子
に接続する。これにより、第１の変流器１８の１
次巻線の有効巻数が前記電動機に応じた値に切り
替えられ、抵抗器群２８の抵抗器のうち前記電動
機に応じた抵抗値を有する抵抗器が整流回路２６
に接続される。
なお、第４図に示す装置６０の場合、第１の切
替スイツチ２２により第１の変流器１８の２次巻
線１８2の有効巻数が切り替えられる。[Table] When the electric motor 14 is operating, the electric line 34c from the power supply 12
The current supplied to the motor 14 via the first current transformer 18 and the first transfer switch 22 flows through the first current transformer 18 and the first transfer switch 22 . As a result, the first and second current transformers 1
A secondary current flows through the secondary windings 18 2 and 20 2 of 8 and 20, the resistors 24 1 and 24 2 of the thermal relay 24 generate heat, and a rectified voltage is obtained at the output of the rectifier circuit 26, and the electric motor The current flowing through the circuit 14 can be determined by the ammeter 32. When the current flowing through the motor 14 is below the rated current of the thermal relay 24, the switch section 240 of the thermal relay 24 maintains the closed circuit state, and each switching section of the electromagnetic contactor 16 maintains the closed circuit state. To maintain this, the electric motor 14 continues to rotate. At this time, the pointer 50 of the ammeter 32 points to the region 56. However, when a current exceeding the rated current of the thermal relay 24 flows through the electric motor 14, the temperature of each resistor 24 1 and 24 2 of the thermal relay 24 becomes high, which causes the switch section 24 0 to open. Each switching section 16a, 16b of the contactor 16 is opened. This prevents the electric motor 14 from being overloaded. At this time, the pointer 50 of the ammeter 32 points to the area 54. After that, the resistors 24 1 , 24 2 of the thermal relay 24
When the temperature decreases, the switch part 240 closes,
The supply of power to the electric motor 14 is resumed. When the device 10 is used with another electric motor having a different rated output, the switching terminal 22 0 of the first changeover switch 22 is connected to a fixed terminal according to the rated output of the motor. As a result, 1 of the first current transformer 18
The effective number of turns of the next winding is switched to a value corresponding to the motor, and the resistor having a resistance value corresponding to the motor among the resistors in the resistor group 28 is connected to the rectifier circuit 26.
connected to. In the case of the device 60 shown in FIG. 4, the effective number of turns of the secondary winding 182 of the first current transformer 18 is switched by the first changeover switch 22.
第１図は本発明の過負荷保護装置の一実施例を
示す電気回路の結線図、第２図は第１の切替スイ
ツチの操作部の一実施例を示す正面図、第３図は
電流計の銘板の一実施例を示す正面図、第４図は
過負荷保護装置の他の実施例を示す電気回路の結
線図である。
１０……過負荷保護装置、１２……３相交流電
源、１４……３相交流誘導電動機、１６……電磁
接触器、１６ａ，１６ｂ，１６ｃ……開閉部、１
６0……電磁コイル、１８，２０……変流器、２
２，３０……切換スイツチ、２４……熱動継電
器、２４0……スイツチ部、２４1，２４2……抵
抗体、２６……整流回路、２８……抵抗器群、２
８1〜２８8……抵抗器、３２……電流計、３４
ａ，３４ｂ，３４ｃ……電力供給用の電路、３６
……電磁コイル用の回路、３８1〜３８8……タツ
プ。
Fig. 1 is a wiring diagram of an electric circuit showing an embodiment of the overload protection device of the present invention, Fig. 2 is a front view showing an embodiment of the operating section of the first changeover switch, and Fig. 3 is an ammeter meter. FIG. 4 is a front view showing one embodiment of the nameplate, and FIG. 4 is a wiring diagram of an electric circuit showing another embodiment of the overload protection device. 10... Overload protection device, 12... 3-phase AC power supply, 14... 3-phase AC induction motor, 16... Magnetic contactor, 16a, 16b, 16c... Switching section, 1
6 0 ... Electromagnetic coil, 18, 20 ... Current transformer, 2
2, 30... Changeover switch, 24... Thermal relay, 24 0 ... Switch section, 24 1 , 24 2 ... Resistor, 26... Rectifier circuit, 28... Resistor group, 2
8 1 ~ 28 8 ...Resistor, 32 ... Ammeter, 34
a, 34b, 34c...Electric circuit for power supply, 36
...Circuit for electromagnetic coil, 38 1 to 38 8 ...Tap.
Claims (1)
て該電路を開閉する開閉部および該開閉部を制御
する電磁コイルを備える電磁接触器と、１次巻
線、２次巻線および該１次巻線または２次巻線に
接続された複数のタツプを備える第１の変流器で
あつて前記１次巻線が前記電路に直列に接続され
る第１の変流器と、該第１の変流器の前記２次巻
線に接続される抵抗体および該抵抗体の温度に応
じて開閉されるスイツチ部を備える熱動継電器で
あつて該スイツチ部が前記電磁コイルへ電力を供
給する回路に組み入れられた熱動継電器と、切替
端子およびこれに選択的に接続される複数の固定
端子を備える第１の切替スイツチであつて前記固
定端子が前記タツプに独立的に接続された、前記
電路と前記第１の変流器との間または前記第１の
変流器と前記熱動継電器との間に組み入れられた
第１の切替スイツチと、１次巻線および２次巻線
を備える第２の変流器であつて該１次巻線が前記
抵抗体を経て前記第１の変流器の前記２次巻線に
接続された第２の変流器と、該第２の変流器の前
記２次巻線に接続された整流回路と、切替端子お
よびこれと選択的に接続される複数の固定端子を
備える第２の切替スイツチであつて前記第１の切
替スイツチと連動して切り替えられる第２の切替
スイツチと、前記整流回路の出力電流を検出し表
示する電流計と、前記電動機を定格が異なる他の
電動機に変更したときに、前記電流計に加わる電
圧がほぼ一定になるように、前記整流回路の負荷
抵抗を補正するための抵抗器群であつて抵抗値が
異なる複数の抵抗器から成り、各抵抗器の一端が
前記第２の切替スイツチの固定端子に独立的に接
続され、他端が互いに共通に接続された抵抗器群
とを含み、前記第２の切替スイツチ、前記抵抗器
群および前記電流計は前記整流回路の出力端子に
直列に接続されている、電動機の過負荷保護装
置。 ２ 前記タツプのそれぞれは前記１次巻線に接続
され、該１次巻線および前記第１の切替スイツチ
は前記電路に直列に接続されている、特許請求の
範囲第１項記載の過負荷保護装置。 ３ 前記タツプのそれぞれは前記２次巻線に接続
され、該２次巻線および前記第１の切替スイツチ
は前記熱動継電器の前記抵抗体に接続されてい
る、特許請求の範囲第１項記載の過負荷保護装
置。[Claims] 1. An electromagnetic contactor that is incorporated into an electrical circuit for supplying power to an electric motor and includes a switching section that opens and closes the electrical circuit, and an electromagnetic coil that controls the switching section, a primary winding, and a secondary winding. a first current transformer comprising a wire and a plurality of taps connected to the primary or secondary winding, the primary winding being connected in series to the electrical path; and a thermal relay comprising a resistor connected to the secondary winding of the first current transformer and a switch section that opens and closes depending on the temperature of the resistor, the switch section being connected to the electromagnetic coil. a thermal relay incorporated in a circuit for supplying power to a switch, a switching terminal and a plurality of fixed terminals selectively connected to the switching terminal, the fixed terminal being independently connected to the tap; a first changeover switch connected between the electrical circuit and the first current transformer or between the first current transformer and the thermal relay; a second current transformer comprising a secondary winding, the primary winding being connected to the secondary winding of the first current transformer via the resistor; a second changeover switch comprising a rectifier circuit connected to the secondary winding of the second current transformer, a changeover terminal and a plurality of fixed terminals selectively connected to the changeover terminal; a second changeover switch that is switched in conjunction with the changeover switch; an ammeter that detects and displays the output current of the rectifier circuit; and an ammeter that is added to the ammeter when the motor is changed to another motor with a different rating. The group of resistors is for correcting the load resistance of the rectifier circuit so that the voltage is approximately constant, and is composed of a plurality of resistors having different resistance values, and one end of each resistor is connected to the second changeover switch. a group of resistors that are independently connected to a fixed terminal and whose other ends are commonly connected to each other, and the second changeover switch, the resistor group, and the ammeter are connected in series to the output terminal of the rectifier circuit. Connected motor overload protection device. 2. The overload protection according to claim 1, wherein each of the taps is connected to the primary winding, and the primary winding and the first changeover switch are connected in series to the electrical circuit. Device. 3. Each of the taps is connected to the secondary winding, and the secondary winding and the first changeover switch are connected to the resistor of the thermal relay. overload protection device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5253685A JPS61214722A (en) | 1985-03-18 | 1985-03-18 | Overload protector for motor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5253685A JPS61214722A (en) | 1985-03-18 | 1985-03-18 | Overload protector for motor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61214722A JPS61214722A (en) | 1986-09-24 |
| JPH0480614B2 true JPH0480614B2 (en) | 1992-12-21 |
Family
ID=12917490
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5253685A Granted JPS61214722A (en) | 1985-03-18 | 1985-03-18 | Overload protector for motor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61214722A (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS49103548U (en) * | 1972-12-27 | 1974-09-05 | ||
| JPS5136547A (en) * | 1974-09-20 | 1976-03-27 | Choichiro Hori | Oobaakajuniokeru denkikeihosochi |
-
1985
- 1985-03-18 JP JP5253685A patent/JPS61214722A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61214722A (en) | 1986-09-24 |
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