Sources of Magnetic Fields (1)

Question 1

Four ways to produce a magnetic field:

Answer 1

1. Magnetic Induction
2. Direct Magnetization
3. Indirect Magnetization
4. Mechanical Induction

Question 2

Define Induction

Answer 2

Magnetism produced in a ferromagnetic material by an outside magnetizing force.
- Not from an electrical current

Question 3

Magnetic Induction

Answer 3

A magnetic material becomes magnetized by an external magnetic field.

When a ferromagnetic material is in close contact with a magnet the lines of force from the magnet cause the domains in the ferromagnetic material to align, thus magnetizing it.

Question 4

Indirect Magnetization

Answer 4

Use of a Solenoid (coil) based on the principle that when electrical current is passed through a conductive material a magnetic field is produced at 90° to the direction of current flow.

• magnetic fields get stronger the more the coil is wound
• 5-10 most common

Question 5

Direct Magnetization

Answer 5

Electrical current is passed through a conductive ferromagnetic material longitudinally causing the magnetic field to flow circularly around the part.

• uniform shaped conductive material = uniform # lines of force, value decreases as length of conductor increases.

Question 6

Indirect Induction

Answer 6

(central conductor technique)

• tubes, ring shapes, passageways or hollow sectioned parts
• circular field on both inside and outside surface of part

Electrical current passed through a conductive material to produce circular magnetization in hollow ferromagnetic parts that surround the conductor.

Question 7

Mechanical Induction

Answer 7

Machined ferromagnetic materials can become magnetized due to the directional action of the cutters.