Electromagnetism and transformers

What was Oersted discovery?

Oersted discovered that an electric current produces a magnetic field 

What is electromagnetic Induction?

the production of an electric current

What was Faraday discovery?

The first law of electromagnetism which stated that current is induced by a moving magnetic field.

How to control magnitude of induced current by?

1. strength of magnets

2. speed of motion

3. direction of motion

4. shape of conductor

How does strength of magnets affect the magnitude of induced current?

the stronger the magnet the stronger the current will be.

How does speed of motion affect the of induced current?

The faster the speed the more current will be produced.

How does direction of motion affect the induced current?

When the angle is at 90 degrees, it will create the most amperes to current

then at 45 degrees will be significantly less 

then at if it is perpendicular to the lines of force there will be no current  

How does shape of conductor affect the induced current?

Only when it pertains to transformer, the more loops the more current there will be but the less loops the less current there will be

What is the right rule of thumb?

When placing your right hand on a object the way your fingers are wrapped around the object is , will be the direction of magnetic field lines

What way does the current flow?

It flows from north to south. or negative to positive

What is a solenoid? 

this is a helix with a current. 

What is a helix

this is a coil of wire

What is an electromagnet?

When a solenoid with an iron core running thru the middle of the solenoid.

the iron core is of ferromagnetic material for its magnetic strength. this also needs to be connected to a source of power

What is lenz law?

Also known as the 2nd law of electromagnetism, the INDUCED current flows in the opposite direction of the APPLIED current. Back EMF or principle of self-induction.

So, the applied current flows will run and what comes back will be the induced current

self-Induction

The induction of an opposing EMF in a single coil by its own changing magnetic field

Mutual induction

The magnetic field induces a current in a nearby helix this means that they do not touch or have to operate. 

What is a Generator

Coverts mechanical energy to electrical energy

How does a generator work?

1. wire coil is placed between magnetic poles

2. operation: coil is mechanically turned within field armature, as the coil moves it cuts through the field , then the current induced

What is the difference between a slip ring and a commutator ring?

A commutator ring (have cuts in the ring) will produce direct current that is pulsation, while a slip ring (solid ring) will produce alternating current

Motor

Converts ELECTRICAL ENEGY to MECHANICAL ENERGY

What and how does a motor operate ?

1. Components are the same as a generator, so wire coil between two magnetic poles 

2. Operation: current (I) is passed through the coil then the magnetic field of the Current (I) interacts with permanent magnetic field causing coil to move  X= coming to you O= going away.

what are the types of motors?

there are 2 types, Synchronous and induction

Synchronous Motors

Are coil rotates at same frequency as current @ 60Hz, used in timing circuits in older machines

Induction motors

have stators and rotor, uses electromagnets to create magnetic field to interact with current’s magnetic field, type used to rotate anode in an x-ray tube \

stator= statinary part on the outside that has magnets on it

Rotor = rotating part

transformers

Step up and step down, are usted to change the magnitude of CURRENT & VOLTAGE

Transformers operate on the principle of mutual induction

step up

found in tube circuit also known as HIGH VOLTAGE TRANSFORMER HVT , they increase the voltage 

Step down 

found in filament circuit (used to heat up cathode to boil off electrons), decrease voltage 

Transformers mutual induction

This is the process where a changing magnetic field from primary to secondary by mutual induction

What is another name for primary and secondary circuit?

the primary circuit is (primary or input or applied current 

secondry circuit is (secondary or output or induced current

What is the difference between the step up and step-down Transformers

step up primary has less coils, but the secondary has more coils

step down has more coils in the primary and less coils in the secondary

What is the transformer law voltage

V^p =N^p

V^s N^s

What is the transformer law of amperage

I^s=N^p

I^p N^s

variable trasformer

this regulates the voltage and current that comes in

Auto transformer

only releases what it needs to give out not all the power that goes into it

What makes up a air core

this is two coils

What is an open core

a material like iron inserted into the coils

closed core 

The ferromagnetic material in the coils are connected like a square.
-Direct contact = stronger electromagnetic force

shell type core

Primary & secondary coils wrap around ferromagnetic material together, to form one electromagnet.
-higher current produced with electromagnetic force being kept inside it

Power losses

Copper conductor resistance

hysteresis when magnetic domain is not magnetized in random arrangement

Eddy current is a swirling currents in core minimized by lamination of plates