USING ELECTRICITY Movement Of Electricity Flashcards Preview

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Flashcards in USING ELECTRICITY Movement Of Electricity Deck (20):
0

Parts of an electric motor (4)

Commutator, field cool, brushes and rotating coil

1

______ exist around a current carrying wire

Magnetic fields

2

Magnetic field uses

electric bells, electromagnets, relays

3

Advantages of electromagnets

Can be switched off

4

A current carrying wire experiences ____ when placed in a magnetic field.

Force

5

What does the force in a current carrying wire depend on?

The direction of the current and the magnetic field.

6

How would you reverse the direction of force?

Reverse directing of current/magnets

7

What do field coils do?

Produce a magnetic field

8

Rotating coils

Carry the magnetic field so that there is a force on the coil

9

Commutator

To ensure the motor keeps tiring in one direction in changes direction every half turn

10

What do brushes do?

Provide electric current with good contact

11

In a commercial motor what differences are there with normal electric motor?

Carbon brushes, field coils, mulstinsection commutator

12

Why does a commercial motor have carbon brushes

Good contact but reduced wear and withstand high temperatures.

13

Why does a commercial motor have field coils

Stronger

14

Why does a commercial motor have multiple section commutator

Smooth turning (hundreds of turns)

15

What is a permanent magnet?

A magnet who's magnetic field cannot be switched on and off

16

_____ poles repel and _____ poles attract.

Like poles repel and unlike poles attract.

17

If you increase the current through the wire what happens to the strength of the magnetic field?

It increases

18

How can an electromagnet be made stronger?

Increasing the number of coils of the wire, increasing the current

19

Why would a relay be used?

When is small current circuit is used to control a switch in a high current circuit.