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Flashcards in Magnetism Deck (21)
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1

Define Flux density

A concentration of magnetic lines of force ( flux )

2

Define reluctance

The opposition to magnetic flux

3

Define residual magnetism

The amount of magnetism that remains after magnetic force is removed

4

Define retentivity

The ability to retain magnetism

5

Define permeability

The ability to concentrate magnetic flux ( allowing flux to pass through )

6

Define saturation

When all domains are aligned and magnet can no longer retain magnetism

7

What are the three classifications for magnetic materials

Ferromagnetic (easily magnetized)
Paramagnetic ( can be magnetized )
Diamagnetic (cannot be magnetized)

8

How are hysteresis losses minimized

By adding silicon to the core

9

How are eddy currents minimized?

Laminations

10

State faradays law.

Relative motion between a conductor and a magnetic field will induce a voltage into the conductor.

11

State Lenz's law.

Induce voltage will cause a current to flow in such a direction that it's magnetic effect will oppose the change that produced it.

12

Define inductance.

The opposition to a change in flow of current ( symbol is L )

13

List three factors affecting the magnetic strength of an electromagnet

Core material

Number of turns in the length of conductor

Current

14

When flux lines of a moving magnet cut across a stationary conductor by

Relative motion

15

The strength of a magnetic field is affected by what three things

Core
Current
Number of turns

16

In order to produce a voltage in a conductor, the motion that must exist between the conductor and magnetic field is known as

Relative motion

17

Define flux

Magnetic lines of force

18

Describe hysteresis loss

Flip. Flopping of magnetic domains causing friction, which produces heat, this heat is known as hysteresis loss.

19

Using the left hand rule what does the thumb indicate

The thumb indicates the direction of current flow

20

Name two types of iron losses

Hysteresis and eddy currents

21

Why are iron cores laminated

To minimize eddy current loss