In our daily life we use electric appliances as a matter of course
Well these devices shown here use a single phase induction motor
But how does this motor work, which we plug into the socket?
What are its advantages and disadvantages?
After this video you will have a better idea!
Talking about the single phase induction motor you usually mean the capacitor motor. In this video
we confine ourselves to the capacitor motor. The function of this motor is very similar to the function of the three-phase induction motor.
How this three-phase motor is working was already explained in another video. Please check our playlist
To understand the capacitor motor,
you should first understand how a rotating magnetic field or RMF can be built with only one single phase.
So let us have a closer look at the stator.
The stator consists of a hollow cylindrical core with a number of evenly spaced slots,
which provide the space of the stator winding.
To interrupt the path of the electric eddy currents, this core is made up of stacked laminations
So, let's place a winding within the stator and connect this to AC power supply.
What you see is an alternating magnetic field. But to give the motor a starting torque as well as a defined sense of rotation,
we need a rotating magnetic field.
So how do so?
One possibility to get to a RMF is to create a second, so-called auxilary winding,
displaced by 90 degrees to the main winding.
Furthermore the current in this auxiliary winding is almost 90 degree out of phase.
You get this phase shift by connecting a capacitor in serial.
Now it's time to switch to another view for better understanding.
Due to the capacitor, the magnetic flux of the auxilary winding is perpendicular to the flux of the main winding.
Adding these two flux together, you get the resulting magnetic flux. And yes, - you get a rotating magnetic field.
Because the main winding is about two-thirds of the total winding, the resulting RMF is elliptical.
Here you see a RMF with two poles. Of course, you can build also a RMF with four or more poles.
So, let's have a look to the inside of the motor. As you learned, the RMF is built within the stator.
The rotor, the moving part of the motor, consists of bars with end caps on each side.
Therefore you can name this motor also as squirrel cage motor.
To enhance the magnetic field of the rotor and therefore the torque, the rotor bars are mounted within a pack of steel laminations.
As the stator magnetic field rotates,
voltage is induced within the bars of the rotor.
As the rotor bars are shorted at both ends, there is a closed path for the flow of current.
This in turn produces an own magnetic field in the rotor bars, which opposes the magnetic field of the stator.
The direction of the force as a result of the interaction between stator and rotor field, can also be determined by the Lorentz law.
Why slip?
Torque can only be created when rotor current is induced. To say in in other words:
The rotor always has a rotating speed minor to the RMF. This difference is called slip.
As you see,
the function of a single phase induction motor is very similar to the function of a three-phase motor.
So the characteristic curves are also similar.
Several effect determine this curve and you can mark distinctive points. The problem of this motor is its low starting torque.
With a simple trick you can provide a start boost. Add another bigger capacitor in serial to the auxilary winding.
Due to overheating this starting capacitor must be switched off at a certain speed by a centrifugal switch.
Once the induction motor has reached its nominal range, it can maintain its normal speed quite well, even at varying load.
That's because the torque curve is deep at the nominal point. Please watch also our video about three-phase induction motors.
To change the sense of rotation of the motor, the current direction within the auxilary winding must be reversed.
If the manufacturer offers an AC motor with a 6 pin motor terminal board,
you have it very easy to change the sense of rotation.
Just replace the metal jumpers as indicated by the diagram.
All values refer to rated operation.
In rated operation, an induction motor has the best ratio of efficiency to power factor.
The slip in rated operation is between 3 and 7 percent roundabout.
This motor has a nominal speed of 1,400 rpm. With this information
you can evaluate the synchronous rotational speed of the RMF and furthermore the slip.
The power on the motor plate is the mechanical output power. The nominal torque can be calculated with a known equation:
There exists a rule of thumb to determine the run capacitor!
The capacity is between 30 micro farad and 50 micro farad per kilowatt motor power.
As you can see this is a very rough estimate.
The reason is that the size of the capacitor
depends on the motor power and the winding ratio of the working and auxilary winding.
Thus it is very difficult to determine the capacitance. It is best to contact the manufacturer.
The start capacitor, if it exists is about three times as big as the run capacitor.
The rated input power or electrical power can now be determined by a simple equation: The efficiency is a simple ratio.
The insulation class describes the thermal tolerance of the motor windings. The letter indicates the motor windings ability to withstand
operating temperatures for a specific length of time.
The code IP or ingress protection,
defines how well an enclosure protects against the external environment. As the number gets higher the protection gets better.
The first digit defines the protection level against solids; the second against liquids.
You must use both digits to define an enclosure.
Further information about your motor you get from the datasheet
The capacitor motor can be classified as
a synchronous AC induction motor. It is a rather robust motor. But the weak point
is the capacitor and the speed switch (if you have a starting capacitor).
Because the electronics is becoming more and more powerful and cheap,
big single-phase induction motors are replaced more and more by three-phase induction motors controlled by VFD.
You should know that small VFD s can be connected to a single phase voltage.
Subscribe to our Channel and never miss a new video!
For more infomation >> Meet one of the ranchers who invited Speaker Pelosi to tour the border - Duration: 4:21. 
For more infomation >> Гадание на здоровье. Каковы шансы на успешное лечение? | Школа Таро 18+ - Duration: 4:13. 
For more infomation >> Poll shows voters moving towards Trump's national security position - Duration: 4:52. 
For more infomation >> Progressives go after America's innovators and business leaders with new wealth tax - Duration: 5:05. 
For more infomation >> Tracy Morgan on What Men Want & Winning the Lottery - Duration: 2:06. 
For more infomation >> 【 志祺七七 】你是否也覺得「政治正確」很煩？追求公平正義錯了嗎？《 生難字彙大辭海 》EP 006 - Duration: 7:00. 
For more infomation >> Những Nhân Vật Háo Sắc Nhất Trong Tiểu Thuyết Của Kim Dung - Tốp 5 Lạ Kỳ 🔥🔥🔥 - Duration: 10:29. 
For more infomation >> Grebek Guru-Guru TK-SMAku di Surabaya! - Duration: 32:54. 
For more infomation >> ZING SPEED MOBILE | Review Xe B RAZOR | Ông Trùm Xe B Cực Mạnh Trong Rank Sao Băng Và Nhiều Hơn Thế - Duration: 20:00. 
For more infomation >> 终于透露三胎DNA曝光，張柏芝遭三胎親父拋棄，謝霆鋒接其回豪宅，三胎姓名曝光竟然隨媽姓？ - 娛 樂 新 聞 - Duration: 2:49. 
For more infomation >> Những món ăn đem lại may mắn ngày Tết của các nước láng giềng - Duration: 3:07. 
For more infomation >> SPOTİFY ÜCRETSİZ PREMİUM HESAP ALMA | 2019 YOUTUBE İLK SESLİ ANLATIM - Duration: 2:39. 
For more infomation >> Intro 🅱 - Duration: 6:45. 
For more infomation >> Volvo V40 T3 150PK benz 60000 KM Summum Leer | Stoelver | Trekhaak - Duration: 1:14. 
For more infomation >> N. Hulot va retrouver la tête de sa fondation - Duration: 4:42. 
For more infomation >> Nissan QASHQAI 1.2 N-Connecta Navi/Camara/Led/Keyless/Panoramadak/18inch - Duration: 1:15. 
For more infomation >> 1/29/19 11:50 (Modletice 139, 251 01 Modletice,) - Duration: 19:56. 
For more infomation >> 迪麗熱巴《ELLEMEN》官宣！她一改往日的甜美造型 - Duration: 4:17. 
For more infomation >> Chelsea latest news: Deja vu for Chelsea and Manchester United in the FA Cup - Duration: 3:07. 
For more infomation >> 谁8分钟能单挑第一条主宰？李白没机会，韩信看经济，图四随便打 - Duration: 3:58. 
For more infomation >> Why I'm still Vegan - CLICKBAIT - Duration: 1:45. 
For more infomation >> カナダ人彼氏が感じた日本人とカナダ人の違い！| Japasen Guys and Japanese Girls【国際ゲイカップル】 - Duration: 6:08. 
For more infomation >> FIFA 14 MOD FIFA 19 Android Offline 900MB New Face Kits & Transfers Update Best Graphics - Duration: 15:00. 
For more infomation >> ПОЧЕМУ Я НЕ МОГУ ПОХУДЕТЬ. - Duration: 3:15. 
For more infomation >> ПРОИЗВОДСТВО ПЛАСТИКОВОЙ УПАКОВКИ ФЛАКОНЫ Minipress.ru - Duration: 1:23. 
Không có nhận xét nào:
Đăng nhận xét