STARTER MOTOR

A starter motor consists of  a pinion gear also known as a one way clutch ,bushes ,armature ,commutator,poles and field coils .and also has a solenoid connected to it which controls the power to the starter motor . the job of the starter is to receive power from the battery which ingadges the pinion gear  to the flywheel and turns it realy fast to crank the engine over and get the engine started .

i carried out some tests to check the starters condition . i did a pull in winding test on the starters solenoid you use a power box and hook a positive lead up and a negative lead up then put the positive lead to the s terminal  and the negative to ground their should be a amp draw between 8-12 amps to be in good condition .i also did some visual checks to make sure  it was visually ok and there was no major damage to the parts .also did a no load test and on 12 volts it should make between 30 to 50 amps to be working propery

ALTERNATORS

I learn't that the rotor is the electro magnet that takes power from the stator and the rectifier controls where the power goes. Also we measured the brushes and the minimum brush length 4.0mm to be in good working order .We also connected a power box tester  to the alternators regulator to test for a short circuit , if the short circuit light on the power box shines bright their is a short circuit . if the light blinks it should be ok .I also did a test on the rectifier to test for negative diodes .by using a multimeter on the ohms scale then put the common lead to the E terminal of the rectifier and the red lead to the p terminal on the rectifier the resistance should be low .and when puting the red lead on the E terminal of the rectifier and the common lead to the p terminal their should not be a voltage drop higher than 0.5-0.7 for it to be in good working order .
In a rotor winding ground test it should show infinite on the ohms scale of the multimeter .and on a internal rotor winding resistance test it should show between 2-6 ohms on the multimeter for it to be in good condition .Also the job of the alternator is to keep the battery fully charged and run  the accessories of the car e.g. lights ,stereos,electric fans, airconditioning  and the ecu .

BATTERIES

A fully charged car battery should be 12.6 volts and you need atleast 12.4 volts to start a car .
the other purpose of the battery other than giving power to the starter to start the car are running the accessories when the cars off eg: alarms ,stereos ands keeping power to the ecu to maintain its memory .
If one cell in a battery has failed the whole battery needs replacing because you can not fix the cell at fault .
To get rid of the surface charge on the battery you can turn on the head lights for two minutes or you can disconnect the positive coil wire or the positive ignition plug and crank the engine over for 15 secounds .
when load is applied to a battery it must hold above 9.5 volts to be in  working order any lower is a failed battery also when testing only crank tester to half the cold cranking amps of the battery and do this for 15secs .when  cleaning a battery use warm water and baking soda to clean acid away  and coat terminals in grease or petroleum jelly .

a battery can be very explosive around naked flames because batterys give off hydrogen gas which is very flammable .

SAFETY

safety is a important thing to remember when in and around the workshop .
their are safety requirements like long sleeve and long legged overalls to stop skin contact with any dangerous
liquids and also protects against getting loose clothing or jewelery caught in moving machinery .
you also need steel capped boots which proctect your feet from any heavy objects crushing your feet .
you may also need to wear protective glasses or earmuffs . you would wear the glasses to protect your eyes from any harmful liquids or flying metal or any other objects . You would use ear muffs when using loud machinery to protect your self from any long term damage. you also need to be mature and responsible in a work shop to prevent any serious injury  caused by being an idiot . a must not in a work shop is to not cosume alcohol or drugs because this could affect ur awareness and result in injury .
you should also have a first aid certificate to show you know what to do if you or some one else is injured
in the work place .also the use of axel stands are a good precation to stop the car falling on u when the car is jacked up axel stand stop and prevent crush injuries from happening .these are  some of the safety precautions you should take in a work shop.

CIRCUITS

• There are 3 different types of circuits . their is a series circuit , a parallel circuit  and their is compound circuits .

SERIES CIRCUIT

in a series circuit the users or the components are in a series to each other for example :

also if their is a 12 voltr battery supply it is shared between the two components in the circuit .

so if you made a two bulb series circuit the bulbs would be using about 6volts each and the amperage stays the same but the resistance is increased . In class we made this circuit by using some wires and a circuit bord with a switch light bulbs and a fuse and i linked all these components together in series . and we ran some tests using a multimeter and i checked the voltage drop by runing the multimeter across the components to check for bad switches or faulty connections .

PARALLEL CIRCUIT

In a parallel circuit you have a battery input  and a out put which goes to ground .

a parallel circuit is when all the users or components eg. light bulbs are in parallel row form here is an example of a 3 bulb parallel circuit . The voltage is aproxamitly the same throughout the bulbs because unlike a series circuit the available voltage dosen't change because all the lights have their own power supply and there own ground .

COMPOUND CIRCUIT

a compound circuit is when there are light bulbs or components in parallel and series to each other

so if you made a compound circuit for example you would have two bulbs in parallel and one bulb in a series and it would look something like this :

i learn't that when working out calculations of the resistance of a compound circuit always work the total of the parallel circuit first .and they all get round about the same volts because there only one light in series and the two in parallel have there own battery supply so the 1 series light bulb gets the same because there is nothing taking power from it . we also checked the v.d over the circuit the series had the biggest drop because it use all its power .