## How does a commutator reverse the current?

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 will a motor not work without a commutator?

Why will a motor not work without a commutator? Without commutator it will not rotate and the armature oscillates between north and south poles. No motor action. … Without commutator it will not rotate and the armature oscillates between north and south poles.

## Can commutator convert AC to DC?

Commutator and Brushes They are also used on some AC motors such as the repulsion, synchronous, and universal motors. All generators produce a sine wave, or AC currents when the rotor turns in the magnetic field. The commutator on the DC generator converts the AC into pulsating DC.

## What are the disadvantages of DC motor?

Disadvantages of DC motorsHigh initial cost.Increased operation and maintenance cost due to the presence of commutator and brush gear.Cannot operate in explosive and hazard conditions due to sparking occur at brush (risk in commutation failure)Oct 20, 2017

## Which motor is better AC or DC?

Which Motor Is More Powerful: AC or DC? AC motors are generally considered to be more powerful than DC motors because they can generate higher torque by using a more powerful current. However, DC motors are typically more efficient and make better use of their input energy.

## Why is a split ring commutator used 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 will happen if there is no split ring commutator in electric motor?

Explanation: 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 is advantage of DC motor?

DC motors offer highly controllable speed. By changing the armature or field voltage it’s possible to achieve wide speed variation and with this level of controllability, DC motors offer the precision required by a wide range of industry applications.

## 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 causes commutator arcing?

Poor undercutting of commutator: If the commutator has high mica or fins of mica that reach up to the brush surface, vibration and sparking may result.

## How do you check if a motor is good?

With a multimeter set to low ohms (usually 200), test between each winding terminal and the metal casing of the motor. If there is any reading on any of these then the motor is bad, do not use it. You may find that when it runs ungrounded that the casing becomes live at up to supply voltage.

## How do you tell if a motor is shorted out?

Test for direct shorts in the motor’s power windings in induction (non-brush type) motors. Keep the multi-meter set for 30,000-ohms and touch one test lead to one terminal and the other to another terminal. Each of the sets of windings should read about the same ohms value.

## What is the difference between commutator and slip ring?

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 happens if you run a DC motor on AC power?

As the motor is DC so the field and armature winding made for DC supply. The winding which is made for DC always has more resistance than the winding which is made for AC. … For this reason, the motor will be run in very less speed on AC supply. When DC motor Runs on AC supply more loss and heat will occur in the motor.

## Can a commutator be repaired?

Mold-type commutators are not repairable and must be replaced if damaged. When a commutator comes in for a repair, units are disassembled and rebuilt with new copper and mica segments using the same quality assurance processes applied to new commutators.