Moving Iron Vane Movement:

The moving iron vane movement could be used to measure both AC current and voltage. Through changing the meter scale calibration a movement could be used to measure DC voltage and current. The moving iron vane meter operates on the principle of magnetic repulsion among like poles. The measured current flows by a field coil that generates a magnetic field proportional to the magnitude of current. Suspended within this field are two iron vanes attached to a pointer. Both two iron vanes consist of one fixed and one moveable vane. The magnetic field generated through the current flow magnetizes the two iron vanes along with the similar polarity regardless of the direction of current by the coil. Since like poles repel each other, the moving iron vane pulls away from the fixed vane and moves the meter pointer. That motion exerts a force against a spring. A distance the moving iron vane will travel against the spring depends on the strength of the magnetic field. The Strength of the magnetic field depends on the magnitude of current flow.

Figure: Moving Iron Vane Meter Movement

As begins previously, this category of meter movement might also be used to measure voltage. Whenever this type of movement is used to measure voltage, the field coil consists of several turns of fine wire used to produce a strong magnetic field along with only a small current flow.