What amperage is required for circular magnetization of a bar that is 381 mm long and 51 mm in diameter using a 7-turn coil?

To determine the required amperage for circular magnetization of a bar, one needs to consider the parameters of the bar and the coil through which the current will flow. The formula generally used for circular magnetization is based on the concept of magnetizing force, which can be derived from the coil's geometry, the number of turns in the coil, and the dimensions of the test specimen.

In this case, the length of the bar is 381 mm and its diameter is 51 mm. When utilizing a 7-turn coil, the total magnetizing force (H) produced by the coil can be calculated by a formula that incorporates the number of turns, the current (I), and the dimensions of the bar. The relationship suggests that as the diameter increases, the required current also increases proportionally to generate an effective magnetic field capable of saturating the material.

The formula can often be represented as:

[ H = \frac{N \cdot I}{L} ]

Where:

• N is the number of turns,

• I is the current in amperes, and

• L is the length of the magnetic path (often this can be approximated by the length of the cylindrical bar).

Given that there are 7 turns and considering