Component for rotating machines: brush-segment

Brush-segment

The brush-segment component is a switch describing the electrical contact between a segment of the commutator segment and the brush in a D.C. machine.

Utilization

This component is used in transient applications and requires the use of kinematic coupling.

Brush-segment: characteristics

The brush-segment component is characterized by five parameters:

• the on state resistance R_on in Ohms
• the off state resistance R_off in Ohms
• the angular position of the commutator segment with respect to the brush position θ_pos in degrees
• the brush opening angle θ_brush in degrees
• the opening angle of the commutator segment θ_bar in degrees

Brush-segment: operation

Conductance of brush-segment component (negative θ_pos).

The brush-segment component is in full conduction whenever the mechanical angle of the rotor (θ_mec) is opposite to the angular position of the commutator segment with respect the brush (θ_pos).

Thus, we have conduction of the brush-segment starting from θ_mec = θ_pos

Description of a commutator

To define the commutator of an electrical machine that includes N brushes and M commutator segments, it is necessary to connect each brush to the M commutator segments. Thus, it is necessary to create N*M brush-segments components.