Commutators and brushes are used on all DC generators and DC motors. They are also used on some AC motors such as the repulsion, synchronous, and universal motors. … The commutator on the DC generator converts the AC into pulsating DC.
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 do brushes do in a AC 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 instrument is used to check run out of commutator?
Using a MTI Microtrak 4 laser triangulation sensor to measure a DC motor’s armature / commutator bar run out.
What is the causes of sparking of motors?
Sparking can be caused by numerous conditions like motor overload, vibration, high humidity, worn brushes and worn commutators. When checking for sparking or arcing, a good visual inspection of the commutator and brushes will have to be performed.”