What is a commutator and how does it convert AC to DC?

Commutator and Brushes All generators produce a sine wave, or AC currents when the rotor turns in the magnetic field. The commutator on the DC generator converts the AC into pulsating DC. The commutator assures that the current from the generator always flows in one direction.

How does a commutator reverse current?

In a generator the commutator picks off the current generated in the windings, reversing the direction of the current with each half turn, serving as a mechanical rectifier to convert the alternating current from the windings to unidirectional direct current in the external load circuit.

How does the commutator change the AC voltage that is induced in the armature do a DC voltage output?

The commutator mechanically reverses the armature loop connections to the external circuit. This occurs at the same instant that the polarity of the voltage in the armature loop reverses. Through this process the commutator changes the generated ac voltage to a pulsating dc voltage as shown in the graph of figure 1-4.

How does a commutator change polarity?

As the brushes pass over the gaps in the commutator, the supplied electrical charge switches commutator segments, which switches the electrical polarity of the armature coils. This switching of the polarity in the coils maintains the armature’s rotation in one direction.

How can a commutator convert AC voltages on a machine’s armature to DC voltage at its terminal?

A commutator in a DC Machine has alternate bands of Copper and mica. Now when the armature starts to rotate by an external force (in DC Generator), the coils situated in the armature also rotate. The coils are shorted via brush segment with alternate change in influence of poles.

Is commutator present in AC generator?

No commutator is present in AC Generator. To make the current flow in one direction only, DC Generator comprises the commutator.

How can a commutator convert AC voltages on a machine’s armature to DC voltages at its terminal?

Which part of DC machine converts AC into DC magnetic poles armature brushes commutator?

In the case of the DC generator, the commutator is used to convert generated AC in armature into DC.

What is the function of commutator?

The function of commutator ring in an electric motor is to reverse the direction of current flowing through the coil every time coil just passes the vertical position during a revolution. Hence as the direction of the current is reversed, the torque is changed in the direction.

What is the difference between DC and AC commutator?

What a commutator does is change the conductor after a half cycle so a single terminal always experiences same EMF. Figure below shows difference between DC and AC commutator system. While AC commutator system produces an alternating current, DC system would produce a Rectified (full wave) alternating current.

What is the purpose of commutation in a DC generator?

This alternate change via the commutator produces unidirectional current flow. Thus, commutation is the positioning of the DC generator brushes so that the commutator segments change brushes at the same time the armature current changes direction.

What is a commutator on a motor?

The commutator is simply a fancy multi-pole switch. When the AC is in let’s call it the “positive” phase, that fancy switch connects that phase on the rotor to the “positive” DC brush and the opposite phase somewhere else on the rotor to the “negative” brush.

How does an armature coil convert DC to AC?

It doesn’t convert to ac. The armature coils are first connected to dc from the brushes, and current flows in one direction through the armature coil. Then, the coil rotates to align the magnetic field. When it rotates, a new set of commutator contacts are positioned at the brushes.