Chan's Kingdom

Experiment 8-AC Single Phase Induction Motors

I started to take photos of my Power Laboratory experiment for no reasons since my first lab work. Since many do not have the chance to actually operate an AC machine( even my electronics engineering course mates hahaha), ceiling fan and machine machine excluded, I think it’s a good idea I share the photos out.
My theory might not be perfect, so please correct me if you spot any mistake of any kind, I thank you in advance. ( But I wouldn’t go into too much theory though…)
My experiment is divided into Split-Phase motor, Capacitor-Start motor and Capacitor-Run motor. These are all induction motor, operating with a single phase supply. Thus we need to create another phase of supply to provide a rotating magnetic field to turn the rotor.

We used the capacitor-start motor without the capacitor, functioning as a split-phase motor. The auxiliary or the start winding has a high resistance and inductive reactance, while the main winding or the run winding has low resistance and high inductive reactance. Because of the different ratio of winding resistance to the inductive reactance, the run winding current  lags the start winding current, creating a phase difference between them. This creates fields that are out of phase, which in turn produces a rotating magnetic field in the stator. This develops torque in the rotor, starting the motor. ( And almost all of these are copied from my lab manual. Credits to whoever produced these sheets. )

The starting current of split-phase induction motor is 4 to 5 times of their full-load current, thus the starting period has to be short to prevent over heating. ( And I felt the heat after applying power for just 3 seconds!) A centrifugal switch will switch out the start winding ( which has high resistance and will overheat and burn out easily ) once the rotor reaches certain rpm.

A big ass capacitor of the capacitor start motor.

The construction of the motor

Showing the auxiliary winding ( the thinner wire) and the main winding ( the thicker wire).

Closer shot of the windings and also observe the clearance of the stator and the rotor.

The operation of a capacitor-start motor is pretty similar to a split-phase motor. Now we connect the capacitor in series with the auxiliary winding. This provides a rotating magnetic field as well. The cap and winding are disconnected with a centrifugal switch as well.

This is the full setup, including ammeter, voltmeter, wattmeter and electrodynamometer.

Another type of capacitor, mounted for capacitor-run motor.

The capacitor in capacitor-run motor is always connected to the auxiliary winding and power. It doesn’t get disconnected with centrifugal switch. The manual states that it’ll be more quiet at full load, but honestly I didn’t feel the difference. Still vibrating like no body’s business!



This video was taken to find out the starting torque. The scale was too fast for my slow eyes! :(


Another one for measuring starting current.


I would slowly update this blog with my previous and next experiment. Other than Power Lab, I have Advanced Power Electronics Lab as well, dealing with thyristors! Stay tuned. :D

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Labels: Electrical Engineering, Power Lab, USM

Feedly- My Daily Newsletter

Logo from Feedly website

I have been using this for over one whole year now. I think this is a very useful tool so I want to share this out.

Feedly main screen, captured from the website introduction page

Feedly is a subscription tool. It is like a newspaper service, but it operates online. You choose whichever journals, articles or even YouTube channel you like, Feedly will collect their updates and arrange them nicely in your Feedly homepage.

Using Feedly is simple, just go over to the website, register and login, subscribe to your favourite sites so you would not miss any of the updates. So you can subscribe to my blog too if you want!

The biggest challenge for me before using Feedly is that I have too many websites to keep track of. And you would not have all the time to keep refreshing the website to check the updates. And e-mails are quite annoying for me. I used Google Reader before it is gone, then I found Feedly. My subscription ranges from Electronics and Arduino stuffs, to homebrew comical videos and Japanese lesson.

So, use it now to help in your reading. I call mine a One-Stop Reading Corner in this distracting world of Internet.

P/S I am not in anyway affiliated with Feedly. But it would be nice to give me like a one month premium service maybe? Haha.

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Happy Chinese New Year

It’s almost New Year here in Malaysia. My Strike Freedom is still in building process. So I did some photo shooting with a “ang bao” (red packet).

Strike Freedom is still my favourite Gundam until today. Maybe it’s because it is the first model I ever watched? Nothing beats childhood memories I suppose.

This is my sister’s calligraphy writing for Chinese New Year. She got the first prize for a contest in her school with this writing. Sure, it needs some polishing, but at least it’s better than mine.

So, happy Chinese New Year everyone! Wish you guys have a wonderful and prosperous year ahead!

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Labels: Gunpla, Strike Freedom

MBF-P02 Gundam Astray Red Frame from Daban Model

Hi guys. This is a Gunpla I finished like months ago. I did not have the time to properly take photos for this awesome figure! ( Its build is actually more playable than Akatsuki… My Akatsuki has a very weak leg peg that keeps falling off…)
Anyway, this is my first time taking photos for gunpla ( okay, not the first time, but this is the first trial of me trying really hard to pose the figure!), used one whole day with some intermittent breaks haha.

The standing pose. I tried hard to make it as cool as possible…

Side view

I was trying a sword drawing pose. It turned out harder than I thought. Now I can appreciate the flexibility of human joints.

First try of a dynamic pose for a Gunpla. But it’s a must for Red Frame. It’s built for this!

This would have looked nice if I am taking photos outdoor. The reflection would be amazing.

Here comes the big sword!

But apart from looking cool behind, sword form… is really just a prop… LOL.

Now I can fly!

This is how I am posing Red Frame on my shelf now. By the way, I bought a new shelf, that’s why I pulled this model out of its box. It’s a shame not to showcase this guy. It’s stunning!
That’s all from me. Feel free to comment on my lousy skills, be it building or photoshooting. I made a lot of mistakes everywhere. Cheers!

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Labels: Daban Model, Gundam Astray Red Frame, Gunpla