Q&A

What produces a magnetic field in a DC motor?

What produces a magnetic field in a DC motor?

In a DC motor, DC running through the wire winding creates the magnetic field. Each time the armature rotates by 180°, the position of the north and south poles are reversed. If the magnetic field of the poles remained the same, the rotor would not turn.

What produces the magnetic field on the armature?

The armature is mounted on bearings and is free to rotate. It is mounted in the magnetic field produced by field poles. This magnetic field might be produced by permanent magnets or an electromagnet with its magnetism produced by a current passing through the, so-termed, field coils.

What happens if AC is fed to DC motor?

When AC supply is given to DC series motor: An AC supply will exert unidirectional torque because the direction of armature current and field current reverses at the same time and the direction of rotation will as it is.

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What type of current does a DC motor produce?

direct current
The two major types of electric motors are: AC motors, which are powered by alternating current. DC motors, which are powered by direct current.

How an electric current can produce a magnetic field?

As Ampere suggested, a magnetic field is produced whenever an electrical charge is in motion. The spinning and orbiting of the nucleus of an atom produces a magnetic field as does electrical current flowing through a wire. The direction of the spin and orbit determine the direction of the magnetic field.

How are electric magnetic fields used in motors?

Electric motors use the forces produced by magnetic fields to produce a turning motion. If you put a length of wire in a magnetic field and pass a DC current through it (such as from a battery), the wire will move. This is called the motor effect .

What is field current and armature current?

The field of a synchronous generator is the winding to which the DC excitation current is applied. The armature is the winding to which the load is connected. In small generators, the field windings are often on the stator, and the armature windings are on the rotor.

How AC sine wave is generated in the armature of the DC generator?

AC Generation Summary The sine wave output is the result of one side of the generator loop cutting lines of force. In the first half turn of rotation this produces a positive current and in the second half of rotation produces a negative current. This completes one cycle of AC generation.

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How is the speed of a DC shunt motor related to the armature current?

(3) we can say, speed is inversely proportional to armature current. Thus, when the speed of the dc motor is increased, the armature current will decrease.

What will happen when the DC motor is connected to AC supply then DC motor will run at rated speed DC motor will burn DC motor will run at slow speed both 2 & 3?

What will happen if DC shunt motor is connected across AC supply? Explanation: In case of parallel field connection, it won’t rotate at all and will start humming and will create vibrations, as a torque produced by positive and negative cycle will cancel out each other. DC motor will be heated up and it may burn.

What is armature and field in DC motor?

The armature is the winding to which the load is connected. In small generators, the field windings are often on the stator, and the armature windings are on the rotor. A synchronous motor is virtually identical to a synchronous generator. Thus, the armature is the stator and the field is the rotor. DC machines.

How current is produced in motor?

Current from the brushes flows through the commutator and one winding of the armature, making it a temporary magnet (an electromagnet). The magnetic field produced by the armature interacts with a stationary magnetic field produced by either PMs or another winding (a field coil), as part of the motor frame.

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Can a DC motor produce current on its own?

A DC motor, by itself, cannot produce current or voltage unless it is fitted with an armature that can continuously turn or rotate inside an external magnetic field. Even a generator, DC or AC, cannot produce current by itself unless the generator output is connected to a load (lamp, or resistance).

How to adjust the voltage of a DC motor?

Voltage can be applied to the terminals of the DC motor or external resistance can be applied in the armature. Another method is to vary the flux per pole of the motor. The first two methods involve adjusting the motor’s armature while the latter method involves adjusting the motor field.

What is the difference between armature and field controlled DC motors?

Field controlled DC motors are more common for longer processes due to their reliability and convenience. Unlike armature controlled motors, field control provides speeds that are above the normal range. The main advantages of this method include: Lower costs: The field control method is a highly economical form of motor control.

How do you reverse the flow of current through an armature?

Often use a control circuit that uses magnetic contractors to reverse the flow of current through the armature – only the current through the armature changes direction. The current flow through the shunt and series fields remain the same