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How does a DC commutator work?
Commutators are used in direct current (DC) machines: dynamos (DC generators) and many DC motors as well as universal motors. In a motor the commutator applies electric current to the windings. By reversing the current direction in the rotating windings each half turn, a steady rotating force (torque) is produced.
What is the commutation in DC machine?
Commutation in DC machines is the process by which the reversal of current takes place. In DC generator this process is used to convert the induced AC in the conductors to a DC output. In DC motors commutation is used to reverse the directions of DC current before being applied to the coils of the motor.
How does a commutator change AC to DC?
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.
What is commutator machine?
an electric machine, such as a generator or motor, in which the rotor winding is connected to a commutator. Commutator generators are used mainly to supply three-phase alternating current; they make possible control of the current frequency independent of the speed of rotation of the generator rotor. …
Why are brushes used in DC motors?
They can either be graphite or precious metal brushes which have electrical motor connections. To supply power to the rotor we put in place a brush system and each of the brushes have a direct voltage symbol (+/-). The brushes are connected to the commutator bars which allows the current to flow into the winding.
What is ideal commutation?
(also called straight-line commutation) is that in which the current of the commutating coils changes linearly from + to in the commutation period as shown in Fig. The figure also shows delayed commutation and the current in the spark. …
What is the function of commutator in DC machine?
Converting dc to ac
What is the function of a commutator in a DC generator?
The commutation in DC machine or more specifically commutation in DC generator is the process in which generated alternating current in the armature winding of a dc machine is converted into direct current after going through the commutator and the stationary brushes.
What are things use DC motors?
Small DC motors are used in tools, toys, and appliances . The universal motor can operate on direct current but is a lightweight brushed motor used for portable power tools and appliances. Larger DC motors are currently used in propulsion of electric vehicles, elevator and hoists, and in drives for steel rolling mills.
What are the uses of commutator?
A commutator is a rotary electrical switch that periodically reverses the direction of the current between the rotor and the external circuit. The commutator was discovered by William Ritchie and Hippolyte Pixii in 1832. Commutators are used in DC machines ( DC motors and DC generators) as well as in universal motors .