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.

 

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.

Electrical Appliance Maintenance : Rice Cooker

 It's a vacation day fro you and you all preparing some foods to enjoy. Food means like heaven when it's delicious. You need to cook that food to make it like heaven,but unfortunately you rice cooker isn't working. OMG!!!! what you going to do dummies. Well pack up your tools dummies because we going to repair a rice cooker.

Rice cooker works as same as electric kettle and electric iron box. It change rice cooker turn electrical energy into heat energy. You need water to achieve your rice cooker can cook your rice and make steam to make fishy food. YUM!!! YUM!!!.

It has same component that has in electric kettle and electric iron box. A heating element and thermocouple. As usual a heating element turn electrical energy into heat energy. SO the heating element has resistance to make heat. Rice cooker comes with variety of design. But in common inside a rice cooker has huge pot made of aluminum. So when the heating element heating, It need water to distribute heat to the pot.That's the reason water is needed.

In thermocouple works like electric kettle (Not like electric iron box. It has thermostat to control heat). When the water or food heat at in higher temperature, the thermocouple will turn off the rice cooker immediately. So Life will be easy if you have rice cooker.

how it maintain a rice cooker in order to make it last long.

1) Check the continuity of power cord of your rice cooker. If the cord fails to power your rice cooker, you need to replace new power cord. The continuity of the cable must in  0 ohm.

2) Check the resistance of heating element. If the heating element fails, you food wont cook and your need to use your stove. So use multi meter and check the resistance of the heating element. If the reading is not accurate than your reading done by calculation, you need to replace new on. Use R=V/I to calculate the resistance value.

3) Check the continuity of thermocouple. If the thermocouple fails, it also damage the heating element and your rice cooker. You can feel your rice cooker too hot and don't turn of automatically, that the sign the thermocouple get spoil. So use multi meter to check continuity on thermocouple,if it fail replace new one.The continuity value must be 0 ohm.

TO MAKE YOUR RICE COOKER LAST LONG CHECK THE COMPONENT ONCE IN TWO MONTHS. IF DON'T WORK COMPLETELY THROW AWAY AND BUY NEW ONE. MAYBE PANASONIC RICE COOKER IS GOOD I GUESS.