Tuesday 8 November 2016

What happen when short circuit happen in electrical outlet and appliance

Every time you use your electrical outlet that connected to electrical appliance and it works good. But suddenly a sparks created in the electrical appliance and get burn or explode. The MCB that connected to the electrical outlet trip. So What the heck happens? Well dummies if you read my previous post (Fault in Electrical Circuit) You probably know that is short circuit. The questions is what happen when a short circuit get in electrical outlet and appliance? Lets find out.
Short circuit is an electrical circuit fault,when different current carrying conductors contact each other. Like Neutral wire contact Live. When this happen you MCB will instantly trip in order to protect your electrical appliance and rid you from getting shock.  

When you look into further, When a live wire bypass to neutral accidentally, the current will increase and the voltage will be near zero. This is because the conductor of both wire is less resistance. This is why current increase in first place. The reason why voltage becomes zero is as we know voltage is a electrical potential. When the conductors bypass another conductor, the voltage will choose the less resistance path that make the voltage zero.

Using Ohm's Law you can also see when the resistance is 0 The voltage is zero too. So the current will get higher. When short circuit occur a huge sparkles with arcs. This is dangerous to human when comes to contact with it. even contact with water is so dangerous. 

There's some benefits from short circuit that people used to do everyday like welding. Grounding the metal with ground cable and hold live wire with welding electrode. when the electrode touch the ground,it will make sparks and arc to melt the electrode and stick to the metal. 

There's also a dangerous thing about short circuit. It cause you to pass out or second degree burn on you. So stay away when short circuit happens. Short circuit even happen in DC also. Like in electronics,if the components didn't solder rightly, the component might pin will touch other component to make short circuit.


 In Overhead transmission line also can be short circuit if the distance between the cable is so closely. 

FOLKS YOU HAVE TOO BE ALWAYS AWARE OF ELECTRICAL ACCIDENTS. IT MAY HAPPEN ANYTIME. ALL YOU NEED TO DO IS MAKE YOURSELF SAFE. SAFETY FIRST.

Monday 7 November 2016

Electromagnetism : Three phase Motor

Factories!!!! Conveyor belt machines!!!! Mixer!!!. These three things has something one in common. That is really fascinating us to know what is the common thing. Let me give you clues. These three things usually used in factories and some used in homes to. It rotate all time depends on user and it's cheap. Well dummies if you guess three phase induction motor, and you are right. Dummies lets learn about three phase induction motor that going to amaze your mind.

The picture above shown is the exploded view of three phase induction motor. The main two parts of AC three phase induction motor is the stator and Rotor.The stator is the stationary part and the function as you know earlier that produce rotating magnetic field. The rotor is the rotating part. The rotor is a squirrel cage design that short circuit in end rings. These will allow rotor to rotate by inducing magnetic field in rotor.



Lets go to the interesting part. It's the working principle of Three phase motor.  If you compare single phase induction motor, you can easily spot the difference in three phase motor. Like in three phase motor has Three phase windings. Means each phase has it's own windings. When the three phase supply flows to the each stator windings and it will energize. The energize each phase windings will give a rotationg magnetic field that runs  at synchronous speed. To calculate the synchronous speed the formula is : 

While the rotating magnetic field runs in synchronous speed, the rotating magnetic field will energize the rotor. This will produce and EMF in the rotor and produce a force to rotate the rotor by Lorentz's force law. This rotation will make a three phase sinusoidal wave. This means each phase has it'a own sinusoidal wave in order to rotate the rotor.




It's look interesting to see how this three phase motor works. But there's a little glitch in the rotor. Like in synchronous motor, the rotor with permanent magnet or external DC power supply, will follow the stator rotating magnetic field in constant synchronous speed even load is added. But in this induction motor, The rotor first follow the synchronous speed. Eventually the when the both stator's rotating magnetic field and rotor comes with same speed, it will slow down and speed up again. This rotor speed never achieve the synchronous speed. This phenomena called 'Slip' Note that dummies. To calculate the slip the formula is :

Every things has benefits and some drawbacks. Same goes to this induction motor dummies. The advantage is less maintenance and less cost. this is why it's widely used in factories. Furthermore, it also has self starting that doesn't require external force or adding special windings.

 The disadvantage of this induction motor is it produce huge amount of heat actually can fried an egg :P just kidding,There's a fan mount back of the motor to dissipate the heat. The torque is reduce when load is added and didn't make constant synchronous speed. Finally it has less efficiency than a synchronous motor.

 IT BEEN 8 MONTHS I START THIS BLOG AND GAIN 3K VIEWS. I THANK YOU TO PEOPLE FROM ALL OVER THE WORLD WHO READ THIS BLOG AND UNDERSTAND THE WORLD OF ELECTRICITY. SHARE THIS BLOG AND CONTACT ME OR EMAIL ME TO DISCUSS OR TALK ABOUT ELECTRICAL TOPICS. 
TILL THEN STAY ELECTRIFY

Friday 4 November 2016

The Lorentz Force Law

We seen how magnetic field behaves when interact with conductor, as today we know motors. What makes a motor rotate by itself without starting by external force? This kind of question commonly everyone has. Well dummies it's all about Lorentz force. So lets discuss about Lorentz force law.

Lorentz force Law says When a electric charge Q flows in a magnetic field B,The force occur in both the direction of magnetic field and charge are perpendicular. 
  
This is easily determined by Right Hand rule and Right hand Fleming's rule too. The right hand rule indicate the thumb as the direction of current flows and other 5 fingers refer to the direction of magnetic field. While in Fleming's right hand rule state is force is perpendicular to the direction of current flows and the direction of magnetic field.


This force created by electric charge such as electron flows in a conductor that exert in magnetic field. When the electron moves in the magnetic field, it feels a force that might the force goes upward or downward. This force cannot be don't if the electron move parallel to the magnetic field. This is because the force will be zero if move parallel to the magnetic field. The equation for this will be :
Applications Of Lorentz's Force Law

1. Electric Motors
 
Electric motors are run by this force. Example your toy car DC motor. When the conductor in rotor by external DC power supply, the rotor will rotate.
 
2.Northern Lights (Aurora)
 
When solar charge particles hit the earth magnetosphere (Earth's Magnetic Field),The particle will spiral along with earth's magnetic field and get the beautiful northern light.
 
3.Speaker   
 
When a speaker's coil is energize it's vibrate the diaphragm with the permanent magnet due to the Lorentz force generate in the coil,
 
 
WELL DUMMIES I HOPE YOU UNDERSTAND MORE ABOUT ELECTRICAL. IF HAVE ANY QUESTION OR TOPIC TO DISCUSS, COMMENT BELOW OR CONTACT ME 
 
 
  

Monday 31 October 2016

Current kills you!!!! Not voltage


The sign "Danger High Voltage,Keep Out" always piss you off when you go near high,medium or low voltage transmission,generators,transformers and so on. So why these signs always warn people to scare away to avoid get electric shock? Well the common answer is you get shock when you accidentally touch leakage cable or electrical panel. This answer only a regular person says,but a trained professional electrician will stay cool even he/she get near high voltage. So what actually make a person get shock? Well lets talk about this question.

Every person in the world have been get electric shock by many ways,including me XD. If you a electrical enthusiast, you will know what is voltage,amperage and resistance that you learn in fundamentals of electricity. There's the clue to find out what makes us get electric shock.


To understand further, lets open a tab water. When you open a tab water the water will flow out. Imagine the water pressure is acts as a voltage. Voltage is a form of energy that has potential to flow in any direction in a circuit. The water flow that comes out of tab actsa amperage or current. Current means flowing of electron to one point and to another point.
The the tab valve or size represent as  resistance.

When water pressure is high, the water flow will be high or vise verse if the water pressure is low. In change if you add resistance you can control the water flow that represent as current. So if high pressure as high voltage with high resistance can less the amount of current. In this case even less current with high voltage you can actually get harm because the high voltage pushing the current in high potential push the current so high. But this harm cannot be done by low potential voltage. It must go high to low.


Let say your house have 240V with 100mA current. This 240V will push the 100mA current in high potential to low potential. If you touch the wire that carrying this potential, you will get shock and didn't get harm because the current is less to harm you even it flows in high potential. In High voltage like 22KV in transmission line has high potential and high current.
This high voltage flows the current in high potential. This will definitely will burn you if you touch it.  

In conclusion, voltage is the energy that push the current flows in the conductor. So you need voltage and current to make you get shock!!!!!! Current is the real culprit to get you  shock.
 

Sunday 30 October 2016

Electromagnetism : How synchronous motor works


Motors are cool!!. It power machines,cars,toys and so on. This is all cause of electromagnetism. Some motors, the stator will provide rotating magnetic field and induce the same electromagnet to the rotor. But there's some motor create separate electromagnet in order to rotate the rotor. So Kind of motor we going to learn about. It called The 'Synchronous Motor'.

SynchroInous motors are used in cranes,lift and so on. The reason why the motor called 'Synchronous' is the motor rotate at synchronous speed. Why it rotate at synchronous speed ? Well dummies lets find out.

If you read previous post about (Electromagnetism : Squirrel Cage Rotor Vs Wound Rotor) You will understand how these rotor works. So this is how the synchronous motor works.
When the stator gives three phase supply through slip ring,the stator winding will energize. The slip ring is add with external resistance because the huge amount of current can cause windings burn.

  While the rotor will energize by external DC power supply Alternatively, a permanent magnet also can done this process in rotor. So both stator and rotor creates it own magnetic field separately as you can see the schematics at the picture shown above.
 When both get magnetic field separately, The stator revolving magnetic field and rotor magnetic field will align according to the opposite pole. This will make the rotor rotate at synchronous speed.

To calculate the synchronous speed, there's number of poles (P), motor's frequency (Hz) and Angle of degree (120) are include in synchronous speed formula.


Although the motor rotate at synchronous speed, but the motor will not self start because it's lock with stator revolving magnetic field with rotor constant magnetic field. This will eventual damaged the motor by applying external load. To overcome this problem the wound rotor is redesign by adding damper windings A.K.A squirrel cage to induce magnetic field into the damper windings to self start.
Synchronous motor is used in huge fan blower,compressor,pumps and so on. The advantage of this synchronous motor can provide power factor correction and have high efficiency than induction motor. Even loads is are apply to this motor, it will remain the same synchronous speed.But the down side of this motor is have high maintenance and high cost

ELECTRIFYING FACT OF THE DAY :
THE OPPOSITE OF SYNCHRONOUS MOTOR IS CALLED ASYNCHRONOUS MOTOR.
A  ASYNCHRONOUS MOTOR IS AN INDUCTION MOTOR RUN BY INDUCE  REVOLVING MAGNETIC FIELD ON ROTOR WHILE SYNCHRONOUS MOTOR DO THE OPPOSITE.