Can You Grease Brushes on an Electric Motor?

Some electric motors use carbon brushes to energize the rotor.
••• ancient fan image by Luisafer from Fotolia.com

An electric motor is essentially a coil of wire spinning inside a magnetic field. In certain motor types, carbon brushes conduct power to the spinning coil through contact with a commutator, which "commutes" (sends) power to the coil.

Brush Function

Motor brushes remain stationary as the motor turns. They contact the commutator, transferring electricity to the commutator. The commutator is segmented with each segment corresponding to a different coil. As the rotor turns and commutator turns the brushes contact different segments, one at a time.

Brush Wear

When the motor is turning, the brushes and the commutator continuously come in and out of contact because the commutator is segmented. This places wear on the brushes in addition to the friction of sliding on the commutator.

Electrical Contact

The brushes must contact the commutator or the motor will not function. Attempting to lubricate the brushes with grease would cause the brushes to lose contact with the commutator. Graphite, a form of carbon used for lubrication, provides the main ingredient in motor brush manufacturing making other lubricants unnecessary.

Related Articles

What Are the Functions of Parts in an Electric Motor?
Parts of a Motor
The Difference Between a Brushed & Brushless Motor
How to Make Electromagnets Repel
How to Hook Up a 480V, 208V, or 120V Transformer
How to Use Log on a TI-83
How to Make an Electrical Circuit with Paper Clips
What Are Resistors Used for?
How to Convert Horsepower to kWh
How Do AC Motor Starters Work?
What Are the Functions of a Magnetic Contactor?
Parts of Induction Motors
What Is a Centrifugal Blower?
What Is a Hydraulic Power Pack?
Motor Rewinding Procedures
Can You Repair a Burned-Out Electric Motor?
What Is an Electric Relay?
How Do Push Button Switches Work in an Electrical Circuit?
What Makes the Wheels Move on a Car?