introduction to motor.doc

I. Course Objectives課程主題:After this course candidates will be able to通過本課程學習,各同事可以:1. Recognize basic characteristics of Johnsons products.對約翰遜產品特性有基本的認識;2. State different applications of Johnson motors.明確約翰遜馬達不同的運用.3. Select appropriate motor model for different motor characteristic requirements.選擇合適的馬達型號以滿足不同的馬達特性需求.II. Introduction引言This course module provides an introduction of basic motor theory for Johnson Electrics products-本課程介紹約翰遜電氣產品的馬達基本原理,AC universal motor, synchronous motor, shade-pole motor as well as the application characteristics如交流通用馬達，同步電機，罩极電機以及高壓直流電機的運用特性.of HVDC motor. It also involves the introduction of motor characteristics such as input, motor 同時會涉及一些馬達的特性,如輸入,馬達效率,efficiency and output performance etc., together with their application.輸出性能等,以及其它的運用.III. Motor TypeIII馬達類型A. High Volt Direct Current Motor (DC)高壓直流馬達(DC)A1 Introduction引言Johnsons HVDC motor is the DC motor that applied in rectified supply of 100240 V/AC, the 約翰遜高直流馬達是用100240V交流電源整流後供電的馬達,motor theory is same as LVDC motor except that 其原理同低壓直流馬達一樣,it requires a rectifier in application and its effect has to be taken into consideration.除開它需要一個整流器及它的效率需要考慮之外.It applies over 50V input voltage that needs to meet safety regulation.它的供電電壓超過了50V,這就需要滿足安規.A2 Rectification整流器A3 Advantage (in comparison with universal motor)優點(對比通用馬達)Stable current flow that is suitable for electronic circuit control電流穩定適於電氣電路控制High torque in relatively compact size尺寸小,輸出扭力大Lower no load speed that will be quiet operation and no damage to gear-train in gear-drive application空載轉速低,運行無噪音且不會損傷齒輪驅動馬達的齒輪.A4 Disadvantage 缺點Expensive magnet component電磁元件昂貴A5 Typical life time一般壽命時間50hour to 200 hours50200小時A6 Normal life ending phenomenon正常壽命終止時表現為Wear out of carbon brush碳刷磨損用完.B Universal Motor交直流通用電機B1 Introduction 引言A series commutator machine suitable for use on DC or AC supply一個系列的換向器機器適用交流或直流供電.Confined to fractional-kilowatt ratings because of commutation difficulties由於換向器的難題僅限於分馬力電機.The motor is applicable to vacuum cleaners, hair-dryers, drills and kitchen machines可用於吸塵機,吹風機,電鑽和廚房設施.It is most satisfactory at speeds between 5000and 20000r/min and for intermittent duty so that carbon-安全轉速為5000到20000轉之間,用於間歇性負載,brush and bearing wear is not too rapid.這樣碳刷和軸承不致於很快磨損. RPM n i TorqueLoading Armature I Stator Load speed B2 Design設計A motor must be a “machine” in the mechanical and electrical sense. 一個從機械和電氣觀念上講可說是一臺機器的馬達.It must have a tough protective frame with bearing to withstand axial and radial thrust 它必須有一個堅固的保護外殼來承受軸向和徑向的衝擊;A shaft stiff enough to limit deflection, twisting and eccentricity 一根足夠堅硬的軸以盡量減少撓彎、扭曲及其它的變形;A rotor able to accommodate rotational and clamping stresses and vibration一個合理處理旋轉和鎖緊壓力以及振動的轉子;A well-clamped stack of stator laminations一個良好扣緊的定子芯片;A rigid and truly circular commutator.一個堅固和真圓度良好的換向器.The electrical design areas電氣設計範圍The magnetic design areas磁性設計範圍The magnetic circuit磁力線回路The field and armature windings磁場和電柩繞組The commutator and brushes換向器和碳刷The insulation絕緣材料The cooling system冷卻系統B3.Cooling, Ventilation冷卻和通風系統There is a temperature-rise requirement in the Safety issue for AC electric motor對交流電機來講,在安全問題上有一個溫升控制的要求An appropriate cooling helps to cool down the motor winding temperature, increases the input power 一個合理的冷卻系統可以冷卻馬達繞組的溫度,rating of the unit with respect to increase of fan loading.增加輸入功率等級同時也考慮到風扇負載的增加的影響.Small machines are readily cooled by straightforward circulation of the ambient air小型機器通過簡易的自然通風回路可以很容易的冷卻.For larger machines a separate blower located on the frame drives air into the machine at the commutator 對大型的機器則是安裝一個分離的鼓風機在機殼上,將風吹入機器的換向器端.end. Out at the drive end , augmented where necessary by the provision of fans on the motor shaft; the fan 在驅動的末端以外,則需增加一個風葉在馬達的軸上,may also be used as a balancing disc.此風葉也可用作平衡盤.B4.Commutation換向It involves passing a current through the sliding contact between a brush and the commutator sectors換向涉及到於滑動接觸中,在碳刷和換向器元件之間通過電流的問題.As the commutator bars pass under the brush, the current in the coils to which they are attached is reversed.當換向器條在碳刷下通過時,到它到下一個接觸中,線圈電流會被保持.The brush /commutator assembly碳刷/換向器組件An electro-mechanical contact between brush and commutator bars在碳刷與換向器之間是機電接觸.Emitting the main source of EMI in application在運用中激發EMI主電源.One of the critical factors affecting motor life影響馬達壽命的一個嚴格的因素.C Synchronous Motor同步電機C.1 Motor Design馬達設計The principle of a single-phase synchronous motor with a two-pole permanent magnet rotor is per attached figure兩极永磁式單相同步電機的原理如附圖例.The stator is laminated, all laminations having the same shape定子由芯片組成,所有的芯片外形相同.To allow the motor to be self-starting it is necessary to have an asymmetric air gap為保證馬達能自動啟動,需要不對稱的氣隙設計.The stator is provided with two simple coils, which can be directly connected to the mains定子由兩個可以直接連接到主回路中簡易線圈組成.The rotor consists of a cylindrical permanent two-pole magnet, which is diametrically magnetized轉子由一個圓筒狀的磁极正相反的永久磁鐵組成.C.2 General Characteristics一般特性The synchronous motor described here has some special characteristics and advantages同步電機的一些特殊特性和優點的描述High output per volume 相對體積輸出功率高Materials saving, small dimensions體積小,材料節省High efficiency 高效率Energy saving節能Simple construction結構簡單Suitable for automation適於自動化Constant speed轉速穩定No speed control無速級控制No commutation無換向No anti-interference measures無抗干擾設施Robust reliable超強的可靠性C.3Advantage優點Low cost低耗C.4 Normal life ending phenomenon正常壽命終止表現Wearing of plastic brackets bushing and run out of grease 塑膠座碳刷磨損和潤滑油用完D Shaded-pole Motor罩极電機D.1 Shading Coil罩极線圈This shading-coil arrangement displaces the axis of the shaded poles from the axis of the main poles.罩极線圈用來將罩极的軸線從主极移開.When power is applied to the stator, the flux in the main part of the pole induces a voltage in the shading coil,當定子供電時,在主极部分的磁通量會感應出一個電壓在罩极線圈中,which acts as a transformer secondary winding.其作用好似一個變壓器的二次繞組.Since the current in the secondary winding of a transformer is out of phase with the