What if there is no commutator?
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.
Why does an AC motor not need a commutator?
AC machines do not need a commutator. A commutator converts ac to dc and vice versa. Allow the conversion of ac to dc at the generator’s output. …
What is the speed of DC motor?
DC controls adjust speed by varying the voltage sent to the motor (this differs from AC motor controls which adjust the line frequency to the motor). Typical no load or synchronous speeds for an AC fractional horsepower motor are 1800 or 3600 rpm, and 1000-5000 rpm for DC fractional hp motors.
Why do AC motors need brushes?
The field induces a current flow into the shorted armature whose magnetic field opposes that of the field coils. Speed can be controlled by rotating the brushes with respect to the field axis. This motor has superior commutation below synchronous speed, inferior commutation above synchronous speed.
What is the function of commutator in electric motor?
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 role of brushes in an electric motor?
IN ELECTRIC MOTOR the function of brushes is to make contact with the rotating rings and through them to supply current to the coil. function of commutator in an electric motor is to reverse the direction of current through the coil periodically.
Can commutator convert AC to DC?
The commutator doesn’t allow the current to change direction in the brushes, so it converts AC to DC. The AC current goes up and down. First it goes from 0 to positive, then it goes from negative to positive, and finally it goes from negative to positive.
Which motor is used for blowers?
Induction motors — or (in the context of blowers in particular) often called by the more playful squirrel-cage motors (to avoid confusion with inducer-blower products). In fact, these motors are the most common used in blowers today, as they excel in high-horsepower blower and cooling-fan applications.
Why synchronous motors are not self starting?
Above a certain size, synchronous motors are not self-starting motors. This property is due to the inertia of the rotor; it cannot instantly follow the rotation of the magnetic field of the stator. … Once the rotor nears the synchronous speed, the field winding is excited, and the motor pulls into synchronization.