Which two variables affect the magnetomotive force of a coil?

The magnetomotive force (MMF) of a coil is primarily influenced by the current flowing through the coil and the number of turns (or windings) in the coil. This relationship is defined by the formula:

MMF = N * I

where MMF is the magnetomotive force, N is the number of turns of the coil, and I is the current passing through the coil.

When the current increases, it boosts the magnetomotive force directly, thereby enhancing the magnetic field generated by the coil. Similarly, increasing the number of turns adds to the total magnetomotive force. Each additional winding contributes to the overall intensity of the magnetic field created around the coil.

This foundational principle is crucial in applications involving electromagnets, transformers, and inductors, where controlling the magnetic field strength is essential for their operation. Understanding how current and turns interact is vital for any lineman apprentice working with electrical systems.