ELECTROMAGNETIC DEVICES

Electric Motor, Generator, Induction Motor, Transformers

ELECTROMAGNETIC DEVICES

Electric Motor

device that is supplied with electric current to produce mechanical motion

Commutator Ring

For direct-current motors

Switches the direction of current through the loop

DC, once activated, AC

Slip Ring

AC Motor
CT Scan
counterpart of commutator ring

Armature

rotating part

Electric Generator

Dynamo

A device that converts mechanical energy to electrical energy using Faraday’s law

Can create current without friction

Induction Motor

A type of motor used with x-rays tubes

Used in rotating anode x-ray tubes

Rotor, Stator

Two parts of Induction Motor

Rotor

Rotating part of an electromagnetic induction motor that

Rotor

Consists of bars of copper around an iron core

Rotor

Located inside the glass envelope

Stator

Consists of pairs of stationary magnets (electromagnets) arranged around the rotor

Located in the protective housing

Transformer

A device that transforms voltage & current into higher or lower intensity

Operate only with an AC

Works through electromagnetic induction

Transformer

changes the intensity of alternating voltage and current

Primary Coil, Secondary Coil

two coils in a transformer

Primary Coil

the coil that is supplied with current

Secondary Coil

the coil in which current is induced

Step Up Transformer

Increases voltage from primary to secondary while decreasing milliamperage

Turns ratio greater than 1

Steps up voltage

Steps down current

TR = NS/ NP

Turns Ratio

Law of Conservation, Power

reason why current decrease

Less turns, low voltage, High current

HVT Primary side

More turns, high voltage, low current

HVT Secondary side

Step down transformer

Decreases voltage from primary to secondary while increasing milliamperage

Fixed supply

Turns ratio less than 1

Steps up current

Steps down voltage

Xray tube

no fluctuating supply

More turns (thin copper), high voltage (150V), Low current (0.5-1.0A)

Filament transformer Primary Side

Less turns (thick copper), low voltage (12V), High current (5-8A)

Filament transformer Secondary Side

Anode

step up

Cathode

step down

Transformer Law

Voltage is directly proportional to the number of turns
Current is inversely proportional to the voltage & number of turns