![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisbHnbh54Y2OQLw03bp61K6SbPaHjA6P-ClLITNHPMxTFqyNjCTkgcTXyo7iCROQezgZ6-YCvl2qOB1PVJ-_eb6DK6cFi_JsIfdCHYEdbfZeeNgcYdjCYVEsjAvKBzd1G0-Gc1y-BRPOQ/w441-h368/electrical-motor+%25281%2529.gif)
簡單地用三種比較﹕
1. Synchronous Motor 同步電機 vs Induction Motor 異步電機;
2. Single Phase vs Three Phase;
3. Induction Motor (Squirrel-Cage Rotor) vs Induction Motor (Slip Ring Rotor) ;
1. Synchronous Motor 同步電機 vs Induction Motor 異步電機;
Synchronous Motor 個 rotor係 D.C.經由 slip ring比,個rotor就好似一舊永久磁鐵, Stator rotating magnetic field;
兩者最大分別係Synchronous Motor 加 load 只要唔過個limit, 個轉速都唔會改變;有slip ring, non self started (要D.C.+A.C.), 個lagging or leading can be operated, Efficiency 高啲但又貴啲;响啲需要轉速精準既場合會用到。
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRpZh_jl9CcfqPdEDmPzkQZP5AVLvtq3N8MWJLYjNhNwJ61gXyw8iErvsEzx8Y9kTtOe15w4BSf4S24NBIbNqildi7n8cxgyfkSmomAvYS7l2bWS5eTLZKgU5MkRP8JqMIjNMSN-sDrc0/w267-h233/synchronous+machine.png)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7OLwj6URxYnFyjPEP-quiBqTIycgkwIIq2K2OROguDWnbyfmA-sz3D_A0yxL4knh5Q7hbIAekxtBWwzu7x-OqbLWdNNBzlEdo38G0h8CUh8YwGqOa3xwaaOo5QBzF2kchvvFp8P3UwH4/w399-h223/2020-05-06_231153.jpg)
Induction Motor 係最大路,直接隊電入個Stator後個magnetic field不斷咁轉變就可以啟動個motor, 唔洗任何多餘起動,brush嗰堆嘢通通都唔洗要;個速度好容易通過改變frequency嚟調較;個load increase 個speed會decrease;
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhe_ZX1-1v8t1N606CqDe7ehkIXQXVKAHbPiVwVKcRNVqQhft1OTV7wSv0Y4fUIr7qKjqSchjCOfV9-HBpEN46I9ZtvSA4kIOO_YkFAPj5KYDYYQd-5Xk_bk5GoqHJUiW8Wszs87mMtVTs/w550-h313/2020-05-06_225010.jpg)
更詳盡可參考呢條Youtube:
Synchronous Motor: https://www.youtube.com/watch?v=Vk2jDXxZIhs
Induction Motor: https://www.youtube.com/watch?v=AQqyGNOP_3o
2. Single Phase vs Three Phase;
Single Phase 會揹一隻capacitor 嚟啟動,個功率低啲,會用响風扇、電櫃等家電;
Thress Phase 功率大啲會用响compressor etc.;
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg2N4HcDQeoD4T4aj3icRRk7H-JZZrGAMBB8T46u73E6fDEvtN-rl0Z-SpiFesvc3lV61gUBfMBXcPeIUy4USEqZC5826cn2t-KFX6Ejs6JXshBmIOyHqKNjUkXqdpy5aBRcyi7RPFstkc/w473-h370/2020-05-06_230336.jpg)
更詳盡可參考呢條Youtube:
Single Phase: https://www.youtube.com/watch?v=awrUxv7B-a8
3. Induction Motor (Squirrel-Cage Rotor) vs Induction Motor (Slip Ring Rotor) :
最大分別係後者起動個Torque大啲但電流又細啲,加速起嚟順啲,Speed Control做得好啲;
但複雜咗,即係貴咗之餘又難維修啲。
Slip Ring 主要會用响 lift, crane, hoist machine
更詳盡可參考呢條Youtube: https://www.youtube.com/watch?v=JPn5Ou-N0b0
再補充下直流Motor, 一般Building Services上都唔會用到,係以前玩啲四驅車之類會用得多,得個知字。
特點係用直流比電(廢話),有個brush, 意味住有損耗;
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhYlhWSAZqJ5ePVydabfACiEOESf1OMVDUcsDeMDlDVGYaaxDysB8CnGm5PrXT0jt2rumAxZIv5AiSvwm9qyJCmt-H2FdA8LVebwJH5dKXWv9GGdX0PjRxUARuOBdFhJSQKnPJxfmRxhY4/w578-h379/2020-05-06_215531.jpg)
可以响個Rotor加多幾loop嚟令佢轉速更穩定,以前啲四驅車摩打係三loop
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWKH-dOd_hr9Kwo5IJ6uVzotY_GxE6QEDZmh_5ZxCGv023PRSNy83kCLLTK2Rk9ISWDmq6XtCB9vn5XY30xXtDr6P0KMsjfoqYpb2aW2y2lWpaigPNZgnOQlM23HhMKE14ieJ6F9bbZkA/s320/300307031_m.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiqgyo2RBo6Eff8Q-_I_kaugYCqBoYevQajiliuMKWQny5OGY9fX2rmOnqbpihX6oi7tzdyEQSSglzJMuT8pYrOQeTCxA-vxcFo8fUDhSZ0PFnFo2xGMRazHpUi_KwzfynutEvXXZrZl3s/s320/300308120_m.jpg)
亦可以用組線嚟取代舊永久磁鐵,有兩種駁法,一種係Series, 一種係Shunt
Series特徵係一開始個Torque夠大,但一加Torque的話個Speed會drop得好快
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9wf_L_J2hUzQdHm1C9dHkY8HdnfSzz9crIZ9k8umVbMYnLzZVanPcnNZykznTUWIf3Mj1BQZvigITFo2QB8tRPqVDL-WMbad30W72SOSZ9xnppnQrSFD1joU5O6DiezvMAOTuF91X8x4/w565-h352/2020-05-06_215822.jpg)
Shunt就係一開始個Torque唔大,但加load都話個speed drop得冇咁快
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiUg4FaQousmuP_MAkot-U0Io_EkULuv9BIthBMH2_kZ7C7fgbQ_hfRCDsuBG_EbiMAcoGmpZMVvwa-wlNrVF1d4kpCWrIdCxKTwzIAxP-lsWqvXJ4r08ZwKqyuXQpUUhYfA046n5q6SiY/w567-h344/2020-05-06_220331.jpg)
更詳盡可參考呢條Youtube: https://www.youtube.com/watch?v=LAtPHANEfQo
(Source: Learn Engineering https://www.youtube.com/channel/UCqZQJ4600a9wIfMPbYc60OQ)
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