JP3343095B2

JP3343095B2 - Shredder control device and control method

Info

Publication number: JP3343095B2
Application number: JP35962199A
Authority: JP
Inventors: 俊一横峰; 敬堀; 正阿部; 裕晃米山
Original assignee: アイチ−エマソン電機株式会社; 株式会社明光商会
Priority date: 1999-11-12
Filing date: 1999-11-12
Publication date: 2002-11-11
Anticipated expiration: 2019-11-12
Also published as: JP2001137737A

Description

DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、モータを用いたシ
ュレッダーの制御装置及び制御方法に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control apparatus and a control method for a shredder using a motor.

【０００２】[0002]

【従来の技術】一般的なシュレッダーは、商用電源（例
えば単相１００Ｖ，５０または６０Ｈｚ）を入力とする
インダクションモータと、このモータの出力側に結合さ
れた減速機と、この減速機の出力側に結合される細断機
構とにより構成されている。2. Description of the Related Art A general shredder includes an induction motor which receives a commercial power supply (for example, single-phase 100 V, 50 or 60 Hz), a speed reducer coupled to an output side of the motor, and an output side of the speed reducer. And a shredding mechanism coupled to the

【０００３】インダクションモータで運転されるシュレ
ッダーの運転特性を図３に示す。この図３の特性は、細
断物の負荷に対するモータの回転数の変動を表してい
る。細断物が無い状態の無負荷状態Ｐ１では、回転数Ｎ
１にて運転され、最大細断負荷の状態Ｐ２では、回転数
はＮ２で運転される。細断物が投入され実負荷が大きく
なるとインダクションモータのスベリが大きくなり、回
転数がＮ１からＮ２へと下降する様になっている。した
がって図３よりわかるようにインダクションモータにお
いては、モータが始動し細断物が投入されるのを待って
いる待機状態と、点Ｐ１と点Ｐ２間の特性曲線上におい
て細断物を細断する実負荷運転の状態と、モータへの給
電を停止した停止状態という３つの状態を有している。
常時、細断物の有無に関係なく殆どの場合においてモー
タの回転数は高速域で運転されるように成っている。FIG. 3 shows the operating characteristics of a shredder driven by an induction motor. The characteristic in FIG. 3 represents a change in the number of revolutions of the motor with respect to the load of the shredded object. In the no-load state P1 with no shreds, the rotation speed N
1 and in the state P2 of the maximum chopping load, the number of rotations is operated at N2. When the shreds are thrown in and the actual load increases, the slip of the induction motor increases, and the rotation speed drops from N1 to N2. Therefore, as can be seen from FIG. 3, in the induction motor, the chopped material is cut on the characteristic curve between the point P1 and the point P2 in a standby state in which the motor is started and waiting for the input of the chopped material. There are three states: an actual load operation state and a stopped state in which power supply to the motor is stopped.
In most cases, the motor rotates at a high speed in almost all cases regardless of the presence or absence of shreds.

【０００４】該インダクションモータは商用電源の電流
制限内で最大の細断負荷が得るために、高負荷領域でモ
ータ効率が良くなる様に設計してある。そのため低負荷
領域でのモータ効率が悪い。この様にして設計されたイ
ンダクションモータの負荷−トルク特性及び負荷−モー
タ電流特性を図４に示す。低負荷時の負荷点Ｐ３におい
ての、トルクと電流をそれぞれトルクＴ３と電流Ｉ３と
し、高負荷時の負荷点Ｐ４でのトルクと電流をそれぞれ
トルクＴ４と電流Ｉ４とすると、トルクと電流の比は下
記の式のようになる。（Ｔ３／Ｉ３）＜（Ｔ４／Ｉ４）（１）また、高負荷時Ｐ４はトルクＴ４に要する電流Ｉ４によ
る巻線抵抗での電圧降下が大きく、これを見越してモー
タの巻線仕様が決定されている。しかしながら、低負荷
Ｐ３ではトルクＴ３に要する電流Ｉ３が少なく巻線抵抗
での電圧降下が少なくて済むにもかかわらずモータに印
加される電圧は一定であるので結果として不必要な電力
を供給することになり効率が悪くなっている。尚、図中
のＡはモータ電流、Ｂはトルク、Ｃは励磁電流をそれぞ
れ示す。The induction motor is designed so that the motor efficiency is improved in a high load range in order to obtain the maximum chopping load within the current limit of the commercial power supply. Therefore, motor efficiency in a low load region is poor. FIG. 4 shows load-torque characteristics and load-motor current characteristics of the induction motor designed in this manner. Assuming that the torque and the current at the load point P3 at the time of low load are torque T3 and current I3, respectively, and the torque and the current at the load point P4 at the time of high load are torque T4 and current I4, respectively, the ratio of the torque and the current is as follows. It becomes like the following formula. (T3 / I3) <(T4 / I4) (1) At high load P4, the voltage drop in the winding resistance due to the current I4 required for the torque T4 is large, and the winding specification of the motor is determined in anticipation of this. ing. However, at a low load P3, the current I3 required for the torque T3 is small, and the voltage applied to the motor is constant even though the voltage drop at the winding resistance is small. And the efficiency is getting worse. In the figure, A indicates a motor current, B indicates a torque, and C indicates an exciting current.

【０００５】図５には、インダクションモータの始動時
の時間に対するモータの始動電流の特性を示している。
モータ始動開始時間ｔ８から回転数が安定するまでの時
間ｔ９までの間には、大きな始動電流が流れる。FIG. 5 shows the characteristics of the starting current of the induction motor with respect to the starting time of the induction motor.
A large starting current flows from the motor start start time t8 to a time t9 until the rotation speed is stabilized.

【０００６】[0006]

【発明が解決しようとする課題】従来、インダクション
モータを使用したシュレッダーにおいては、図３に示す
様に大きく分けると細断物が無い状態の無負荷状態Ｐ
１、細断物が投入されモータの回転数がＮ１からＮ２へ
と下がる負荷状態のＰ１−Ｐ２間、細断物が投入され最
大負荷運転状態Ｐ２とそれぞれの動きが区別されるが、
通常細断物の有無に関係なく殆どの場合においてモータ
の回転数は高速域で運転されるように成っている。した
がって負荷に関わらず、回転数はほぼ一定の状態で高速
域で運転され、高速域の回転数にともないモータや細断
機構からの音・振動が発生するために、周辺の環境を著
しく悪化させていた。Conventionally, in a shredder using an induction motor, when roughly divided, as shown in FIG.
1. During the load state P1-P2 in which the shredded material is supplied and the motor rotation speed decreases from N1 to N2, each movement is distinguished from the shredded material and the maximum load operation state P2.
In most cases, the motor rotates at a high speed in most cases regardless of the presence or absence of shreds. Therefore, regardless of the load, the motor is operated in the high-speed range with the rotation speed almost constant, and noise and vibration from the motor and the shredding mechanism are generated with the rotation speed in the high-speed range, which significantly deteriorates the surrounding environment. I was

【０００７】また、シュレッダーにおけるインダクショ
ンモータの設計は高負荷状態を重視して設計されている
ため、高負荷において最も効率が良く運転できるように
なっている。従って、細断物を細断していない無負荷状
態や低負荷状態においてはモータ効率が悪くなり必要以
上に電力を消費している。このことは図４より明らかで
あるが、モータ電流Ａと励磁電流Ｃとの関係より判るよ
うに低負荷時Ｐ３におけるモータ電流に占める励磁電流
の割合は、高負荷時Ｐ４のモータ電流に占める励磁電流
の割合より大きくなるためである。[0007] Further, since the induction motor in the shredder is designed with emphasis on a high load state, it can be operated most efficiently at a high load. Therefore, in a no-load state or a low-load state in which the shredded material is not shredded, the motor efficiency deteriorates and power is consumed more than necessary. This is apparent from FIG. 4, but as can be seen from the relationship between the motor current A and the excitation current C, the ratio of the excitation current to the motor current at the low load P3 is higher than the excitation current at the high load P4. This is because the current ratio becomes larger than the current ratio.

【０００８】仮に、消費電力を抑えるために、細断物を
細断していない時にはモータを停止したとしても、新た
に細断物が投入される度にモータを始動させるので、頻
繁に大きな始動電流が流れるため消費電力は有効に低減
されない。また図５のように頻繁に大きな始動電流が流
れるためモータが過熱しモータ効率を悪化させたり、過
熱することによる人体への危険が発生し、有効な解決手
段がなかった。Even if the motor is stopped when the shredded material is not shredded in order to reduce the power consumption, the motor is started every time a new shredded material is introduced, so that a large start-up is frequently performed. Since current flows, power consumption is not effectively reduced. Further, a large starting current flows frequently as shown in FIG. 5, and the motor is overheated, thereby deteriorating the motor efficiency or causing a danger to the human body due to overheating, and there is no effective solution.

【０００９】[0009]

【課題を解決するための手段】本発明は、供給される電
源とモータ間に、該モータを可変速する制御手段を設
け、細断する細断物の有無によって運転状態を切り替え
る制御であり、また細断物がない場合には、低速運転状
態もしくは、運転停止状態とすることにより、モータや
細断機構から発生する音・振動を低減し、消費電力を有
効に低減させる。According to the present invention, there is provided control between a power supply to be supplied and a motor, wherein a control means for varying the speed of the motor is provided, and the operation state is switched according to the presence or absence of a chopped object. In addition, when there is no shredder, a low-speed operation state or an operation stop state is set to reduce noise and vibration generated from the motor and the shredding mechanism, thereby effectively reducing power consumption.

【００１０】本発明の第一、第二の実施例を図面に基づ
いて説明する。図１は本発明による制御の流れをタイミ
ングチャートにて説明したものである。細断する細断物
が無い場合には、低速度運転状態もしくは、運転停止状
態としている。制御手段が検出手段の信号によって細断
物が有ると判断した場合には、ｔ１−ｔ２、ｔ３−ｔ４
間の様にモータ回転数を上昇させ細断運転状態とする。
制御手段が細断物検出手段の信号によって細断物が無い
と判断した場合には、ｔ２−ｔ３間の通りモータ回転数
を下降させ、低回転状態とする。また、設定時間以上経
過した場合にはｔ５の様にモータの回転数を下降させ通
電を停止する様にしている。また、低速運転状態を運転
停止状態としても良い。First and second embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a timing chart illustrating the flow of control according to the present invention. If there are no shreds to be shredded, it is in the low speed operation state or the operation stop state. When the control means determines that there is a shred according to the signal of the detection means, t1-t2, t3-t4
In the meantime, the motor speed is increased to bring the state into the shredding operation.
If the control means determines that there is no shredder based on the signal of the shredder detection means, the motor rotation speed is decreased as between t2 and t3 to bring the motor into a low rotation state. When the set time has elapsed, the motor rotation speed is decreased to stop the energization as at t5. Further, the low-speed operation state may be set to the operation stop state.

【００１１】従来技術の課題としては、商用電源等の電
圧がそのままモータに印加されるため、運転停止状態か
ら新たに細断物が投入される度にモータを再始動させる
ことになり、頻繁に大きな始動電流が流れ消費電力は有
効に低減されなかった。また、頻繁に大きな始動電流が
流れるためモータが過熱し、モータ効率が悪化したり、
人体への危険が発生したりし有効な解決手段がなかっ
た。本発明は、商用電源とモータとの間だに、モータを
可変速できる制御手段が介在し調整することが可能であ
るため、大きな始動電流が流れることなく、モータを始
動することができるため、モータが過熱しモータ効率を
悪化させるこがない。また、細断物がない場合には、低
速運転状態もしくは、運転停止状態とすることにより、
モータや細断機構から発生する音・振動を低減し、また
消費電力も有効に低減することができる。尚、モータ仕
様については所望の用途に合せて、ＤＣモータ、ＤＣブ
ラシレスモータ、リラクタンスモータ等、適宜変更する
ことができる。As a problem of the prior art, since a voltage of a commercial power supply or the like is applied to the motor as it is, the motor is restarted every time a new shredded material is supplied from the operation stop state, and the motor is frequently restarted. A large starting current flowed and power consumption was not effectively reduced. In addition, the motor often overheats due to frequent large starting current, which reduces motor efficiency,
There was no danger to the human body and no effective solution. According to the present invention, since a control means capable of varying the speed of the motor can be interposed and adjusted between the commercial power supply and the motor, the motor can be started without flowing a large starting current. The motor does not overheat and the motor efficiency does not deteriorate. In addition, when there is no shredded material, by setting the low-speed operation state or the operation stop state,
Sound and vibration generated from the motor and the shredding mechanism can be reduced, and power consumption can be effectively reduced. Note that the motor specification can be appropriately changed to a DC motor, a DC brushless motor, a reluctance motor, or the like according to a desired use.

【００１２】図２は、本発明の制御手段による始動時の
時間に対するモータの始動電流特性を示す。モータ始動
開始時間ｔ６から回転数が安定するまでの時間ｔ７まで
の間は、従来のインダクションモータによる始動時の時
間に対するモータの始動電流の特性を示した図５と比べ
ても判る様に、モータ始動電流における大きなピークが
発生しないため滑らかな電流特性が得られる。そのた
め、頻繁に大きな始動電流が発生しモータが過熱しモー
タ効率を悪化させたり、過熱することによる人体への危
険を回避することができる。FIG. 2 shows the starting current characteristics of the motor with respect to the starting time by the control means of the present invention. From the motor start time t6 to the time t7 until the rotation speed is stabilized, as shown in FIG. 5, which shows the characteristics of the starting current of the motor with respect to the starting time by the conventional induction motor, as can be seen from FIG. Since a large peak does not occur in the starting current, a smooth current characteristic can be obtained. For this reason, a large starting current is frequently generated and the motor is overheated, thereby deteriorating the motor efficiency or avoiding danger to the human body due to overheating.

【００１３】次に、本発明のシュレッダーにおいて細断
物検出手段の信号によって細断物の有無を判断する場合
の検出手段について説明する。本発明の第三の実施例を
図面に基づいて説明する。図６は制御手段が細断物検出
手段の信号によって細断物の有無を判断する制御方法を
示したブロック図である。交流電源１と制御手段２内の
直流変換部４との間に電流検出手段３を設ける。電流検
出手段３は変流器等により構成され、交流電源１から直
流変換部４に流れる入力電流を検出して、制御部６へ信
号を出力する。入力電流の大小でモータ負荷を推測し、
細断物の有無を制御部６で判断して運転状態を切り替え
る。また、電流検出手段３だけでなく電圧検出手段を設
けることにより、入力電力の大小で細断物の有無をより
正確に判断することも可能となる。Next, a description will be given of a detecting means in the shredder of the present invention for judging the presence or absence of a shredder based on a signal of the shredder detecting means. A third embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a block diagram showing a control method in which the control means determines the presence or absence of a shred according to a signal from the shred object detection means. Current detecting means 3 is provided between the AC power supply 1 and the DC converter 4 in the control means 2. The current detecting means 3 includes a current transformer or the like, detects an input current flowing from the AC power supply 1 to the DC converter 4, and outputs a signal to the controller 6. Estimate the motor load based on the magnitude of the input current,
The control unit 6 determines the presence or absence of shreds and switches the operation state. Further, by providing not only the current detecting means 3 but also the voltage detecting means, it becomes possible to more accurately determine the presence or absence of a shredded object depending on the magnitude of the input power.

【００１４】本発明の第四の実施例を図面に基づいて説
明する。図７は制御手段が細断物検出手段の信号によっ
て細断物の有無を判断する別の制御方法を示したブロッ
ク図である。制御手段２内の直流変換部４と電力増幅部
５との間に電流検出手段３を設ける。電流検出手段３は
変流器等により構成され、直流変換部４から電力増幅部
５に流れる直流電流を検出して制御部６へ信号を出力す
る。この直流電流は、モータに流れる電流の合成電流で
ある。モータ電流は負荷に比例しているため、直流電流
の大小でモータ負荷を推測できる。それによって、細断
物の有無を制御部６で判断して運転状態を切り替える。
また、電流検出手段３だけでなく電圧検出手段を設ける
ことにより、直流電力の大小で細断物の有無をより正確
に判断することも可能である。A fourth embodiment of the present invention will be described with reference to the drawings. FIG. 7 is a block diagram showing another control method in which the control means determines the presence or absence of a shred according to the signal of the shred object detection means. The current detecting means 3 is provided between the DC converter 4 and the power amplifier 5 in the control means 2. The current detecting means 3 is composed of a current transformer or the like, detects a DC current flowing from the DC converter 4 to the power amplifier 5 and outputs a signal to the controller 6. This DC current is a composite current of the current flowing through the motor. Since the motor current is proportional to the load, the motor load can be estimated from the magnitude of the DC current. As a result, the control unit 6 determines the presence or absence of shreds and switches the operating state.
In addition, by providing not only the current detecting means 3 but also the voltage detecting means, it is possible to more accurately determine the presence or absence of the shredder depending on the magnitude of the DC power.

【００１５】本発明の第五の実施例を図面に基づいて説
明する。図８は制御手段が細断物検出手段の信号によっ
て細断物の有無を判断する別の制御方法を示したブロッ
ク図である。制御手段２内の電力増幅部５とモータ７の
間に電流検出手段３を設ける。電流検出手段３は変流器
等により構成され、電力増幅部５からモータ７に流れる
モータ電流を検出して、制御部６へ信号を出力する。こ
のモータ電流は負荷に比例しているため、直流電流の大
小でモータ負荷を推測できる。それによって、細断物の
有無を制御部６で判断して運転状態を切り替える。ま
た、電流検出手段３だけでなく電圧検出手段を設けるこ
とにより、モータ入力電力の大小で細断物の有無をより
正確に判断するも可能である。A fifth embodiment of the present invention will be described with reference to the drawings. FIG. 8 is a block diagram showing another control method in which the control means determines the presence or absence of a shred according to the signal of the shred object detection means. The current detecting means 3 is provided between the power amplifier 5 in the control means 2 and the motor 7. The current detecting means 3 includes a current transformer or the like, detects a motor current flowing from the power amplifying unit 5 to the motor 7, and outputs a signal to the control unit 6. Since the motor current is proportional to the load, the motor load can be estimated from the magnitude of the DC current. As a result, the control unit 6 determines the presence or absence of shreds and switches the operating state. Further, by providing not only the current detecting means 3 but also the voltage detecting means, it is possible to more accurately determine the presence / absence of a chopped object depending on the magnitude of the motor input power.

【００１６】本発明の第六の実施例は、シュレッダーの
投入口付近に設置したセンサーによって細断物の有無を
判断することによる別の制御手段を有した制御方法であ
る。The sixth embodiment of the present invention is a control method having another control means by judging the presence or absence of shreds using a sensor installed near the input port of the shredder.

【００１７】[0017]

【発明の効果】インダクションモータを使用しているシ
ュレッダーに対して、細断物の無い時には、低速運転状
態もしくは運転停止状態にすることにより、モータや細
断機構から発生する回転数にともなった音・振動が低減
でき、かつ消費電力が抑えられるので、大幅な省エネ化
と低騒音化が図れる。According to the present invention, when there is no shredder in a shredder using an induction motor, a low-speed operation state or an operation stop state is set, so that the sound generated by the motor and the shredding mechanism is accompanied by the rotation speed.・ Since vibration can be reduced and power consumption is suppressed, significant energy savings and low noise can be achieved.

[Brief description of the drawings]

【図１】本発明の制御方法の実施例を示すタイミングチ
ャート図。FIG. 1 is a timing chart showing an embodiment of a control method according to the present invention.

【図２】本発明の制御方法の時間に対するモータの始動
電流特性図。FIG. 2 is a graph showing a starting current characteristic of a motor with respect to time in a control method according to the present invention.

【図３】従来のインダクションモータにおけるトルクに
対するモータの回転数特性図。FIG. 3 is a characteristic diagram of motor rotation speed with respect to torque in a conventional induction motor.

【図４】従来のインダクションモータにおける負荷に対
するモータの電流特性及びトルク特性図。FIG. 4 is a diagram showing a current characteristic and a torque characteristic of a motor with respect to a load in a conventional induction motor.

【図５】従来のインダクションモータにおける時間に対
するモータの始動電流特性図。FIG. 5 is a graph showing a starting current characteristic of a conventional induction motor with respect to time.

【図６】本発明の第三実施例の制御方法を示すブロック
図。FIG. 6 is a block diagram showing a control method according to a third embodiment of the present invention.

【図７】本発明の第四実施例の別の制御方法を示すブロ
ック図。FIG. 7 is a block diagram showing another control method according to the fourth embodiment of the present invention.

【図８】本発明の第五実施例の別の制御方法を示すブロ
ック図。FIG. 8 is a block diagram showing another control method according to the fifth embodiment of the present invention.

[Explanation of symbols]

１…交流電源、２…制御手段、３…電流検出手段、４…
直流変換部、５…電力増幅部、６…制御部、７…モー
タ、８…細断手段、ｔ０〜ｔ９…時間、Ａ…モータ電
流、Ｂ…トルク、Ｃ…励磁電流。DESCRIPTION OF SYMBOLS 1 ... AC power supply, 2 ... Control means, 3 ... Current detection means, 4 ...
DC converter, 5: power amplifier, 6: controller, 7: motor, 8: shredding means, t0 to t9: time, A: motor current, B: torque, C: exciting current.

───────────────────────────────────────────────────── フロントページの続き (72)発明者阿部正愛知県春日井市愛知町２番地アイチーエマソン電機株式会社内 (72)発明者米山裕晃愛知県春日井市愛知町２番地アイチーエマソン電機株式会社内 (56)参考文献特開昭50−124112（ＪＰ，Ａ) 特開昭62−201657（ＪＰ，Ａ) 実開昭63−1644（ＪＰ，Ｕ) (58)調査した分野(Int.Cl.⁷，ＤＢ名) B02C 18/00 - 18/44 ──────────────────────────────────────────────────続き Continuing on the front page (72) Inventor Tadashi Abe 2 Aichi-cho, Aichi-cho, Kasugai-city, Aichi Prefecture Inside Aichi Emerson Electric Co., Ltd. (56) References JP-A-50-124112 (JP, A) JP-A-62-201657 (JP, A) JP-A-63-1644 (JP, U) (58) Fields investigated (Int. Cl. ⁷⁾ , DB name) B02C 18/00-18/44

Claims

(57) [Claims]

1. A shredder control device for driving and controlling a shredder configured to shred a shredded object, comprising: a motor for driving a shredding mechanism for chopping the shredded object; Control means for controlling the motor at a variable speed interposed therebetween, and shredded material presence / absence detecting means for detecting whether or not a shredded material to be shredded is loaded on the shredding mechanism, The control means switches the operating state of the motor based on the detection result by the shredded material presence / absence detecting means, and when the shredded material to be shredded is not loaded on the shredding mechanism, the operating state of the motor is changed. A control device for a shredder, wherein a low-speed operation state is set, and when the low-speed operation state has elapsed for a set time or more, the operation is stopped.

2. A shredder presence / absence detecting means for applying a shredder to be shredded to the shredding mechanism based on an input current or a magnitude of an input power supplied from the commercial power supply to the control means. The control device for a shredder according to claim 1, wherein it is detected whether the shredding is performed.

3. A shredder presence / absence detecting means, wherein a shredder to be shredded is loaded on the shredding mechanism based on an input current or a magnitude of input power supplied from the control means to the motor. The control device for a shredder according to claim 1, wherein the control device detects whether or not the shredder exists.

4. The control means includes: a DC converter for converting an AC current supplied from the commercial power supply to a DC; a power amplifier for amplifying power supplied to the motor via the DC converter. Current detection means for detecting an amount of current supplied from the commercial power supply to the DC converter, and a control unit for controlling electric power supplied to the motor via the power amplification unit based on a detection result by the current detection means Wherein the shredder presence / absence detection means detects whether or not a shredder to be shredded is loaded on the shredding mechanism based on a detection result by the current detection means. Claim 1
3. The control device for a shredder according to claim 1.

5. A control device comprising: a DC converter for converting an AC current supplied from the commercial power supply to a DC; a power amplifier for amplifying power supplied to the motor via the DC converter; Current detection means for detecting the amount of current supplied from the DC converter to the power amplifier, and control for controlling the power supplied to the motor via the power amplifier based on the detection result by the current detector And a shredder presence / absence detector, wherein the shredder mechanism detects whether or not a shredder to be shredded is loaded based on a detection result by the current detector. Claim 1
3. The control device for a shredder according to claim 1.

6. A control device, comprising: a DC converter for converting an AC current supplied from the commercial power supply into a DC; a power amplifier for amplifying power supplied to the motor via the DC converter. Current detecting means for detecting an amount of current supplied from the DC converter to the power amplifier, voltage detecting means for detecting a voltage output from the DC converter to the power amplifier, the current detecting means, A control unit for controlling power supplied to the motor via the power amplification unit based on a detection result by the voltage detection unit, wherein the shredder presence / absence detection unit includes the current detection unit and the voltage detection Detecting whether a shredder to be shredded is loaded on the shredding mechanism based on a magnitude of DC power supplied to the power amplifying unit obtained from a detection result by the means. Term 2. The control device for a shredder according to claim 1.

7. A control device, comprising: a DC converter for converting an AC current supplied from the commercial power supply into a DC; a power amplifier for amplifying power supplied to the motor via the DC converter. A current detection unit that detects an amount of current supplied to the motor from the power amplification unit, and a control unit that controls power supplied to the motor via the power amplification unit based on a detection result by the current detection unit. The shredded object presence / absence detecting means detects whether or not a shredded material to be shredded is loaded on the shredding mechanism based on a detection result by the current detecting means. Item 1
3. The control device for a shredder according to claim 1.

8. The shredder presence / absence detecting means has a sensor for detecting the presence / absence of a shredder provided in the vicinity of a shredder inlet for feeding the shredder to the shredding mechanism. The control device for a shredder according to claim 1, wherein the control unit switches the operation state of the motor based on a detection result of the sensor.

9. A shredder for shredding by a motor, comprising a control means for varying the speed of the motor between a supplied power supply and the motor, switching an operation state according to the presence or absence of a shredder, and providing a shredding mechanism. When the chopped material to be shredded is not loaded, the operation state of the motor is set to a low-speed operation state, and control is performed so that the operation state is stopped when the low-speed operation state exceeds a set time. Shredder control method.

10. The shredder control method according to claim 9, wherein the presence or absence of shreds is determined based on an input current or input power to control means for varying the speed of the motor.

11. The shredder according to claim 9, wherein the presence or absence of shreds is determined based on current or power immediately after conversion from AC to DC in the control means for varying the speed of the motor. Control method.

12. The shredder control method according to claim 9, wherein the presence or absence of shreds is determined based on the input current or input power to the motor.

13. The shredder control method according to claim 9, wherein the presence or absence of the shredder is determined by a sensor installed near the shredder inlet.