1 Answer. Cosider the simplest of motors, one with a single coil of wire within a fixed magnetic field. … Without a split ring commutator the current would not reverse when armature reverses, and the magnetic fields of the rotor and stator would clash and the rotor will stick in a position and not turn.
What would happen if a commutator were not used in a motor?
Well, without commutator, the machine will not develop a unidirectional torque and motoring action will not take place. In a DC motor, at the instant when armature coil passes through magnetic neutral axis, current in armature coil must reverse to maintain torque in the same direction.
What would be the problem if we do not use a commutator at all?
Without commutator it will not rotate and the armature oscillates between north and south poles. No motor action.
Why does a DC motor need a commutator?
Commutators and brushes are used on all DC generators and DC motors. … On DC and most AC motors the purpose of the commutator is to insure that the current flowing through the rotor windings is always in the same direction, and the proper coil on the rotor is energized in respect to the field coils.
Why is a commutator necessary?
To keep the torque on a DC motor from reversing every time the coil moves through the plane perpendicular to the magnetic field, a split-ring device called a commutator is used to reverse the current at that point.
What is the function of split ring commutator in DC motor?
Split ring commutator function in dc motor:
The split ring has the function of reversing the current at that point. When a dc motor shaft comes into contact with a split ring, the split ring reverses the current to maintain the shaft torque in a magnetic field.
What are the 3 ways to increase the speed at which the electric motor changes?
increasing the size of the current; using a stronger magnet; increasing the number of turns of wire in the coil; reducing friction between the coil and the axel it rotates on.
What are the advantages of DC motor?
DC motors have the advantage of: higher starting torque, quick starting and stopping, reversing, variable speeds with voltage input and they are easier and cheaper to control than AC. AC motor advantages include: lower power demand on start and minimal maintenance.
Can commutator convert AC to DC?
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.
Why starter is used in DC machine?
Starters are used to protect DC motors from damage that can be caused by very high current and torque during startup. They do this by providing external resistance to the motor, which is connected in series to the motor’s armature winding and restricts the current to an acceptable level.
What do brushes do in a DC motor?
The function of the brushes is to conduct electricity to the individual segments as they rotate from brush to brush. This allows the motor to turn in one direction at a speed determined by the number of windings in the armature.
What ways can a motor be made more powerful?
We can increase the turning force (or torque) that the motor can create in three ways: either we can have a more powerful permanent magnet, or we can increase the electric current flowing through the wire, or we can make the coil so it has many “turns” (loops) of very thin wire instead of one “turn” of thick wire.
How does a DC motor work?
How DC motors work. … In a DC motor, the stator provides a rotating magnetic field that drives the armature to rotate. A simple DC motor uses a stationary set of magnets in the stator, and a coil of wire with a current running through it to generate an electromagnetic field aligned with the centre of the coil.
Why does a commutator reverse the current?
The split ring commutator reverse the current in the armature every half revolution when the commutator changes contact from one brush to another. This reverse in current causes the forces acting on the coil to be reversed. This helps the coil continue to rotate in a clockwise direction.
What is the difference between slip ring and commutator?
Physically, a slip ring is a continuous ring, whereas a commutator is segmented. Functionally, slip rings provide a continuous transfer of power, signals, or data. … Commutators, on the other hand, are used in DC motors to reverse the polarity of current in the armature windings.
What does a commutator look like?
The commutator itself is a split ring, typically made of copper, with each segment of the ring attached to each end of the armature coil. If the armature has multiple coils, the commutator will similarly have multiple segments—one for each end of each coil.