Question : Does a Transformer work on DC ?
Answer : Normal transformer does not work on DC, but Pulse Transformer works on DC☺☺.
Question : How ?🧐
Answer : Read this article.
To understand how a transformer works on Dc, you should know the working principle of a transformer.
👉 So what is the working principle of a transformer?
The basic principle of a transformer is Electromagnetic Induction or Mutual Induction. The electromagnetic induction comes from Faraday's law.
The Faraday's law state that an emf is induced in a conductor whenever there is a changing magnetic field and the second law states that the amount of emf induced or the magnitude of emf induced is directly proportional to the rate of change of flux.
Once you understand the Faraday's law, you will realize that the law tells you that there has to be a conductor, there has to be a field and the most important thing there has to be a relative motion between the conductor and the field. Hence there will be a rate of change of flux. In a transformer, the conductors are stationary, so we need to have a moving magnetic field. That's why in AC we provide a moving field and the transformer works properly.
V = 0 indicates short circuit and then due to short circuit there will be too much current in that system, it means the current increase enormously. That's why primary side of the transformer gets damaged. In order to protect the transformer we avoid giving a constant dc supply.
👉 So how will a transformer work on DC ?
Before telling you how it will work, there is a catch here. The transformer, which work on DC is called as Pulse Transformer.
✔ What is pulse Transformer ?
All of you are using a pulse transformer everyday in your life. In public transport or in a train you will notice that there is a 100V DC written on the switch board. And there mobile chargers also work properly on DC. We all know that there is a transformer in your chargers. So now this transformer works on DC. This transformer is known as Pulse Transformer.
WOW ! Really this is ! what is happening when DC is supplied to the pulse transformer?
According to Faraday's law, we need to have a rate of change of current. So now instead of giving a direct current, let gives a pulse current. If we give a pulse current then (di/dt) ≠ 0, so there is some induced voltage. It means no short circuit and no short circuit means primary side is okay, so secondary side is also okay i.e. transformer works fine.
So the conclusion is if you give pulses to the transformer, the transformer will work on DC.
Now the question is in train do we give pulse DC ? DC 100V is written there but no mention that its a pulse DC or constant DC. So how your cell phone chargers are still working ? who is generating the pulse DC?
To understand this we will have a quick look in the circuitry of a charger.
In our home we are giving AC supply to the charger, but when we use in public transport or trains, we are getting DC from switch board. When we give AC as supply, then AC is passed through a voltage divider and rectifier and we get DC as output. When we give DC then DC is also passed through voltage divider and rectifier and get DC as output. So this DC is now being given to a pulse generator, which will generate pulses. Now the pulses are given to the transformer that is sitting in your charger which is pulse transformer and you will get the DC as final output and that DC is obviously charging your cell phone ( 5V, 0.55mA or 2A). For boost charger or fast charger we use 2A and normal charger has 0.55mA.
Transformer will not work on constant DC, but it will work on pulsating DC and it is known as Pulse Transformer.
Now, I hope, you have understood the concept that how a transformer works on DC. If you have any query please comment below.
0 Comments