Why does the primary current in a transformer increase when a load is connected across the secondary?

This is called the exciting, or magnetizing, current. The magnetic field caused by this exciting current cuts across the secondary coil and induces a voltage by mutual induction. The primary current increases as the secondary load current increases, and decreases as the secondary load current decreases.

Why does the primary draw more current when the secondary is loaded?

Power on both sides of the transformer is equal. Less whatever is lost in heat. Your load on the secondary is using energy that was once stored in the transformer’s magnetic field. To replace that energy we will need to have more current from the primary side.

What type of current is used in the primary coil of a step up transformer?

A transformer has two coils – a primary coil and a secondary coil. An alternating current flows in the primary coil and this induces a voltage in the secondary coil.

Does the primary current change with the primary voltage?

The primary must draw enough additional current to set up a field exactly equal and opposite to the field set up by the secondary current. The explanation says that when a load is attached to the secondary, the current in the primary must change to keep the applied voltage field the same.

What happens when an alternating current passes through the primary coil?

When an AC signal is applied to the primary coil, the changing current causes a magnetic field to change (get bigger or smaller). The current passes through the windings creating magnetic flux in the iron core. This flux is traveling through loops of wire on the other circuit.

Why the primary and secondary coils of a transformer are preferably found on the same code?

The primary and secondary coils of a transformer are preferably wound on the same core so as to obtain tight coupling between the primary and secondary on each winding.

When the voltage produced in the secondary coil is greater than the one in the primary then the transformer is said to be?

There are two types of transformer: Step-Up Transformer: If the number of turns in the primary coil is less than the turns in the secondary coil, then it is called a Step-up transformer. A step-up transformer gives voltage greater than the input voltage.

How electric current and voltage change from the primary coil to the secondary coil?

The coils are not electrically connected. the primary coil current produces a magnetic field, which changes as the current changes. the iron core increases the strength of the magnetic field. the changing magnetic field induces a changing potential difference (voltage) in the secondary coil.

Why an alternating current is induced in the coil?

As one side of the coil moves up through the magnetic field , a current is induced in one direction. As the rotation continues and that side of the coil moves down, the induced current reverses direction. This means that the generator produces a current that is constantly changing. This is alternating current or a.c.

What is the voltage in primary?

Distribution Voltages Primary lines have voltages ranging from 2,300 to 39,000 volts. Common primary line voltages are 2,300, 4,160, 12,470, 13,800, 25,000 and 34,500 volts depending on which distribution voltages a utility uses. Common secondary line voltages are 120, 208, 240, 277 and 480 volts.

Why does voltage increase with more turns on a coil?

So while the voltage goes up with more turns, the current you can generate goes down – not just because of resistance but because of inductance, or the ability of the coil to generate a magnetic field in response to a current.

When does a coil experience an induced current when magnetic field varies?

A coil experiences an induced current when the magnetic field passing through it varies. (a) When the magnet moves toward the coil the current is in one direction. (b) No current is induced while the magnet is held still.

Do more turns in the secondary winding of a transformer increase voltage?

So the tricky thing here is that more turns in the secondary winding of a transformer will increase the voltage, but not the power. In fact, the opposite happens. When current is allowed to flow in the secondary winding, it will cause a magnetic field that opposes the magnetic field that caused the current in the first place.

Why is core flux constant in a transformer?

However core flux is thought to be constant as a result to keep core flux constant more magnetising current will be drawn from the primary winding, this will increase the power ration of the primary and induce an mmf and current in the secondary winding. There is a way to work out efficiency and power losses in a transformer if you are interested.