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🚴 | Matsudo City To support the purchase of bicycles for infants


Photo Matsudo City To support the purchase of bicycles for infants

To support the purchase of bicycles for infants in Matsudo City

 
If you write the contents roughly
According to the city, it is the first time for a local government in the prefecture to support the purchase of an electric bicycle that can carry infants.
 

As a child-rearing support measure, Matsudo City is starting an initiative to subsidize the purchase cost of electric bicycles that can carry children ... → Continue reading

 Cibatere + Plus

It will be "Ciba Tele + Plus" operated by Chiba Television Broadcasting.


Wikipedia related words

If there is no explanation, there is no corresponding item on Wikipedia.

electric motor

electric motor(Dendoki,British: Electric motor) Means electrical energyMechanical energyConvert toPower equipment,Prime moverIs the general term for.motor,Electric motorAlso called[1].

In general,magnetic field(magnetic field)When電流Interaction (Lorentz force) Is used to output rotational motion, but linear motion is obtained.Linear motorAnd use ultrasonic vibration without using magnetic fieldUltrasonic motorEtc. have also been put into practical use.Electrostatic forceUsedElectrostatic motorHas been known for a long time.

Originally, the word "motor" ("moter") means "power" and is not particularly limited to electric motors.Therefore, a device that plays a role in some kind of power is often described as a motor (Rocket motorSuch).

In the following, we will mainly explain general electric motors that generate rotational force by electromagnetic force, and other than that.Linear motor,Ultrasonic motorWill be briefly explained at the end.

Electric motor structure

A rotating electric motor has a shaft and rotates.Rotor(Rotor: Rotor) and interacting with the rotorMoment of forceGeneratestator(Stator: Stator), rotation that transmits the rotation of the rotor to the outside軸, Support the axis of rotationbearingCaused by lossheatTo coolCooling deviceIt is composed of.

The part that generates the magnetic field of the rotor and statorFieldThat.

Commutator motor (Brush Motor)Synchronous motorSo, what generates a magnetic field to interact with the field and obtain torqueArmatureThat.

Coupling to connect with load equipment ・ Reduce the number of revolutions for the purposetorqueTo getDeceleratorEtc. are connected as an accessory device.

The commutator motor isCommutatorとbrushThe current flowing through the armature is changed and the direction of rotation is maintained.

Operating principle

There are various types of electric motors, but electric motors have a stator and a rotor, and one of them generates a magnetic field that changes in rotation, and the driving force is obtained by the change in the magnetic field.

Classification by rotor

Except for commutator motors, motors that have a coil in the stator and generate a fluctuating magnetic field by supplying a changing current to the coil can be classified into rotor types.

  1. permanent magnetField (Permanent Magnet Type): If the poles of a permanent magnet are arranged in the circumferential direction, a driving force is generated as the poles of the stator move.
  2. Electromagnet field: Since it is possible to give a magnetic field to the rotor with an electromagnet, both the rotor and the stator are configured to be electromagnets.
  3. Difference in magnetic permeability (Variable Reluctance Type): A driving force is generated by providing a protrusion on the magnetic material so that the magnetic field lines can easily pass through and difficult to pass through.
  4. Arago's disc : If a metal conductor is placed, an eddy current is generated by the change of the magnetic field, and a driving force is generated by the interaction with the magnetic field created by the eddy current.
  5. WindingShapeInduction motor : If a conductor coil is placed, a change in the magnetic field will generate a current that flows through the coil, and the interaction with the magnetic field will generate a driving force.

A plurality of coils on the driving side are provided in order to continuously generate a driving force in a certain direction, and the magnetic phases are shifted in order to generate the driving force.As for the method, various arrangements have been put into practical use.

またRotorとstatorIt can be classified into inner rotor type, outer rotor type, and flat rotor type according to the internal and external positional relationship of.Linear motorIf you apply it toPrimary on-board type-Ground (orbit) linear expressionbecome.

Field and armature current types

Next, there are the following types of current for generating a magnetic field that fluctuates depending on the armature and the primary winding.

  1. Three-phase exchange : A rotating magnetic field can be generated by supplying a commercial three-phase alternating current (a sine wave out of phase by 120 degrees) to three or multiples of the coils.
  2. Single-phase AC: CapacitorIs often used to create another phase that is out of phase.
  3. Variable voltage variable frequency controlInverterThree-phase alternating current by: Commercial three-phase alternating current has a constant frequency, so it is used for starting and changing the speed.
  4. DCPulse: Feeds out-of-phase pulse voltages to separate coils.So-calledStepping motorCorresponds to this.
  5. Commutatorless motor (Brushless DC Motor)SensorThe rotor position is detected by the above, and the polarity of the direct current is switched accordingly.

The classification of DC motors and AC motors can be considered as the classification of usage, not the classification of the structure of the motor, and there may be motors that rotate in either case.

Classification of electric motors

Other classification

  • High-efficiency motor-Complies with high-efficiency motor standards.Less loss than ordinary motors.
  • - FieldTo exciteSuperconductivityElectric motor to use

Electric motor specifications

Motor loss

Motor loss is defined as the difference between input power and output work.

  • Total loss
    • Fixed loss
      • Iron loss : Hysteresis loss / eddy current loss
      •  : Friction loss / wind loss of bearing / cooling device
    • Load loss: Loss that occurs in proportion to load fluctuations

Special electric motor

Most electric motors generate changes in the magnetic field by electricity and generate rotational force by the changes in the magnetic field, but there are special electric motors with other principles and structures as described below.

Linear motor

Linear motorIs a rotary electric motorstatorOn the part that extends in a straight line corresponding toRotorA linear motion is obtained by changing the magnetic field by placing a part corresponding to.There are linear induction motors (LIM), linear synchronous motors (LSM), linear DC motors (LDM), linear stepping motors, linear piezoelectric motors, linear electrostatic motors, and the like.

Vibration motor

Ultrasonic vibration motor
Ultrasonic motorChanges small position changes due to deformation of the vibrating body into rotary motion or linear motion by friction.Lorentz forceLow efficiency compared to conventional motors that use
  • Piezoelectric elementThose that utilize the piezoelectric phenomenon caused by the above are sometimes called piezoelectric motors.It is used for focusing the camera.
Vibration motor
Has been developed for the purpose of vibrating incoming calls on mobile phones and the like.In some small ones, the center of gravity of the rotor is biased and the rotor itself is a weight that creates vibration.

History

principle

1821, British scientistMichael Faraday ElectromagneticAn experiment was conducted to convert electrical energy into kinetic energy by means of a target.Hang the lead wire from above,mercurySoak a little in the pool and put a permanent magnet on it.On that lead電流A round magnetic field is generated around the wire, and the wire rotates around the magnet.[3]..This experiment is often performed in school physics classes, but instead of toxic mercurybrineMay be used.this isHomopolar motorIt is the simplest type of electric motor called.Later improved this Barlow's Wheel There is also.These were only demonstration devices and had no practical structure as a power source.

1827, HungarianJedrik AgnoshStarted experimenting with electromagnetically rotating devices, calling them "lightning-magnetic self-rotors".He uses it for college education, and in 1828statorとArmatureとCommutatorWorld's first practical withDCI succeeded in experimenting with an electric motor.Both the fixed part and the rotating part are electromagnets, and no permanent magnets are used.[4][5][6][7][8][9]..This device was also for experimentation and could not be used as a power source.

Early electric motor

The world's first power source for machinesCommutatorType DC motor is a British scientistWilliam sturgeonInvented in 1832[10]..Following Stajan, he developed a commutator-type DC motor at a level that could be used commercially in the United States and with his wife Emily, and obtained a patent in 1837.This electric motor drove machines such as printing presses at a maximum speed of 600 rpm.[11]..As a power source at that timePower InputThere is no choice but for that electrodezincWas very expensive.As a result, the Davenports failed commercially and went bankrupt.There were several other inventors who developed DC motors, but all faced the problem of power supply costs.At that time, the power grid did not yet exist.Therefore, there was no market for electric motors that was worth the power supply cost.[Source required].

In 1855, Jedrik created a device that did useful work on a similar principle to electromagnetic self-rotors.[4][6].. Also in the same year,Automobile driven by electric motorMaking a model of[12]..However, Jedrik's achievements were not known worldwide and did not affect subsequent motor development.[Source required].

1873 years,Zenobe GrammIs 2GeneratorI happened to discover that the power generated by one can be used to drive the other as an electric motor.This is the world's first commercially successful electric motor[Source required].

1886 years,Frank SpragueInvented a spark-free DC motor that can maintain a constant rotational speed even when the load changes.Around this time, Sprague invented a regenerative technology that returns the power of the electric motor to the power grid.TramWe also invented a method of collecting current from the overhead wire.Using these technologies, in 1887VirginiaRichmondSucceeded in operating a tram in 1892, an electric elevator and its control system, and moreIllinoisChicagoCentralized control type electric subway (commonly known asChicago L) Was successful.Sprague's electric motors and related inventions have exploded the demand for electric motors in the industry, triggering other inventors to invent similar systems one after another.

1888 years,Nikola TeslaIs the first practicalAC motorInvented.Tesla will continue to develop AC motorsWestinghouseContinued at[Source required].

Improving the efficiency of electric motorsstatorとRotorIt was hard to realize that it was important to reduce the gap between the two, and there was no progress for decades.In early electric motors, the gap was relatively large, and the magnetic circuitMagnetic resistanceWas very large.For this reason, the torque that can be generated with the same power consumption is considerably smaller than that of modern efficient electric motors.The reason for this is thought to be that the closer the magnets and electromagnets are, the stronger the attractive force is, so we tried to separate them to some extent.In an efficient design, the gap between the stator and the rotor should be as small as possible to create a magnetic flux pattern that easily generates torque.

Electric motor in Japan

1895 (Meiji 28), Shibaura Seisakusho (currentToshiba) Created Japan's first two-phase induction motor with 6 poles and 25 horsepower (18.5 kW) for copper mine pumps.

1901 (Meiji 34),MeidenshaManufactured a one-horsepower (1kW) three-phase induction motor.

1906 (Meiji 39),MeidenshaHas standardized a three-phase induction motor with 5 horsepower (3.8 kW) or less using its own design method, and started full-scale production as a general-purpose motor.

In 1906 (Meiji 39), a survey as of the end of December,MeidenshaOccupied about 6% of the electric motor Shure in Tokyo.Of the 746 electric motors in Tokyo, 463 were made by Meidensha, and the majority of the remaining 283 were imported products.[13]

A short film about electric motors

Matsushita Electric Industrial Co., Ltd. (currently one of the electric motor manufacturers)Panasonic), In 1963,Power Technology-Motor-A short film (about 28 minutes) entitled "" has been produced.

In this movie work, starting from the explanation of the principle of the motor, the scene of the assembly site of each of the various motor products and the operation scene of the finished product are explained.Tatsuya Jô OfNarrationEntered and introduced.

Here, "Motor" seen in the movie title is a notation based on the German pronunciation of "Motor", which was modeled until the first half of the 20th century. "By the way, at Panasonic, nowadays The notation "motor" is not used (production of motors for general industry continues) >>[1].

This movie work was produced by Tokyo Cinema (currently Tokyo Cinema Shinsha) and is currentlyScience picture museum(NPO corporation, association supporting science picture museum) It is released for free on the website.

Footnote/Source

  1. ^ a b Regarding the katakana notation "motor"Institute of Electrical EngineersIn "motorIn addition to the notation of "motor" depending on the electric motor manufacturerGermanThe notation "Motor" was used as a model for German pronunciation until the first half of the 20th century.Stage pronunciationFollowing the pronunciation based on ""Motor"(Or"Motor”) Can be seen using the notation <<NidecIn the website "What is a motor? 1-3-6.Ultrasonic motorFrom the column "Etymology of Motors" published in the latter half of the page; the notation "motor" is currently at least日立Of seriesHitachi Industrial Equipment SystemとToshibaMainly used in brand names in affiliated Toshiba Industrial Equipment Systems >>
  2. ^ Faraday, Michael (1844). Experimental Researches in Electricity. 2  See plate 4.
  3. ^ spark museum
  4. ^ a b Electricity and magnetism, translated from the French of Amédée Guillemin. Rev. and ed. By Silvanus P. Thompson. London, MacMillan, 1891
  5. ^ Nature 53. (printed in 1896) page: 516
  6. ^ a b Battery and Technology History Timeline Electropedia
  7. ^ http://www.fh-zwickau.de/mbk/kfz_ee/praesentationen/Elma-Gndl-Generator%20-%20Druckversion.pdf
  8. ^ http://www.uni-regensburg.de/Fakultaeten/phil_Fak_I/Philosophie/Wissenschaftsgeschichte/Termine/E-Maschinen-Lexikon/Chronologie.htm
  9. ^ Electrical Technology History Electropedia
  10. ^ Gee, William (2004). “Sturgeon, William (1783–1850)”. Oxford Dictionary of National BiographyOxford, England: Oxford University Press. two:10.1093 / ref: odnb / 26748 
  11. ^ Garrison, Ervan G., "A history of engineering and technology".CRC Press, 1998. ISBN 084939810X, 9780849398100. Retrieved May 7, 2009.
  12. ^ http://www.frankfurt.matav.hu/angol/magytud.htm
  13. ^ "Friend of Electricity" (1906) |

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