Motor Effect

Motor Effect

Put a current-carrying wire in a magnetic field and the wire can be pushed.

That push is the motor effect.

Motor Effect

The motor effect is the force experienced by a current-carrying conductor placed in a magnetic field.

When current flows through a wire inside a magnetic field, the magnetic field of the wire interacts with the external magnetic field.

This interaction produces a force on the wire.

Direction of Force

Use Fleming's Left-Hand Rule.

Hold the thumb, first finger and second finger of the left hand mutually perpendicular.

First finger → magnetic field.

Second finger → current.

Thumb → force or motion.

Force Magnitude

For a straight conductor:

**F = BIL sin θ**

where:

`F` = force `B` = magnetic flux density `I` = current `L` = length in field `θ` = angle between current and magnetic field

Maximum force occurs at:

**θ = 90°**

Factors Increasing Force

Force increases when:

magnetic field strength increases; current increases; * conductor length in the field increases.

Applications

Motor effect is used in:

electric motors; loudspeakers; * moving-coil meters.

Motor Effect — Advanced

The force on moving charge carriers in a magnetic field produces a net mechanical force on the conductor. At conductor level this gives `F=BIL sinθ`.