Starter motor bench testing and repair

Connecting & what Ground testing a windings tell us:

With the meter set on 2K and one lead connected to any end of the widing and the other to a given earth point as depicted in diagram below

The reading must read infinity this means that there is no circuit between the winding and ground ( earth)

Any other reading means that the winding has shorted to earth.

If it has shorted to earth the winding either needs to be replaced or rewound.
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Connections & result of internal circuit resistance testing windings:

With the meter set on 200Ω connect the 2 probes together and get the internal resistance of the meter and leads for example 0.2Ω. This reading will need to be taken away from the actual reading to give you the true resistance value of the winding.

Connect on probe to one end of the winding and the other to the other end as depicted in the diagram below.

The reading in the diagram above is 3.8Ω but it isn't the true resistance. The internal resistance for example of 0.2Ω must be taken away giving a result of 3.6Ω. This is the true resistance and must be within the manufacturer specification.

There are four possible result that you  can get when doing an internal winding resistance test, they are:

Within specification

Open circuit

Lower resistance than Spec

Higher resistance than Spec

Within specification means that the winding has past this test and can be used again.

An open circuit result means there is break in the winding. This requires that the winding is either replaced or rewound; breaks in winding are very rarely repaired. Refer to the diagram below.

Lowe than specified resistance indicates an internal short result. This means that there is break in the insulation of the winding, it hasn't shorted to ground but has shorted to another part of the winding as illustrated in the diagram below.

This allows the current to take a shorter path through the winding effectively lowering the resistance below Manufacturers specifications

This requires that the winding is either replaced or rewound.

Higher than specified resistance can indicate poor winding connection. This could mean there is dirt or corrosion where the winding ends are connected, thus causes a higher than normal resistance.

Poor connections at the ends of the winding may be able to be repaired by removing them and cleaning up the connection points and re-soldering as necessary

Will be given another starter motor and it should also be tested before dismantling.
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No Load Test:
Mount the starter in a test bench, carry out no load test then enter your meter readings in the chart below.

NO LOAD TEST          MANUFACTURERS SPECIFICATIONS          NO LOAD TEST RESULT
Voltage                          No less than 11volts                                              11.70V
Current                          30 to 50 Amps                                                      37.6A

Label the components:

A. Commutator

B. Roller-type/ overruning clutch

C. Brush spring/ Carbon brush.

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Disassembly:

Disassemble the starter in the correct sequence as demonstrated by your lecturer. Failure to follow the correct sequence and procedures may result in damage to the starter motor.

Sequence:

1. Scribe alignment marks along the two end housings and field housing (main body) of the starter motor, this will help to align the major compinents.

2. Remove M terminal wire from the solenoid ( this wire connects the output from the solenoid to the starter motor)

3. Scribe alignment marks on the solenoid body and mounting then remove solenoid

4. Remove any screws in the commutator end housing ( failure to do this can result in major damage to the brushes or field windings).

5. Remove commutator end housing

6. Remove brushes as necessary to remove brush plate assembly

7. Remove field coil housing ( main body of the starter motor)

8. Remove shift fork from drive end housing ( it is important that you mark the position of the shift fork)

9. Remove the armature assembly

10. Remove the overruning clutch from the shaft ( clean any burrs with emery paper for easy removal of the clutch)

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Testing Armature

Visual Inspection:

Visual Inspection- Check for signs of:

Overheating

Burning

Physical damage of insulation and coil windings

Poling

COMPONENT TEST REPORT

ARMATURE     MANUFACTURER'S SPECIFICATIONS     TEST RESULTS          SERVICEABLE

Overheating        Visual Inspection                                          No signs of overheating     No

Burning               Visual Inspection                                          No signs of burning           No

Physical damage  Visual Inspection                                         The insulation was

                                                                                              damaged onto the poling   Yes

Poling                 Visual Inspection                                          The poling has been

                                                                                              damaged by the insulation Yes

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Ground Circuit Tests:

Use a multi-meter in the ohms range and check for:

Ground Short circuit between each of the commutator segments and the amature core or shaft

ARMATURE GROUND TEST

MANUFACTURER'S SPECIFICATIONS          TEST RESULTS          SERVICEABLE

Infinity                                                                    infinity                            Yes

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Continuity Circuit Test

With the ohmmeter in the same range check continuity between one of the commutator segments while moving the second probe around on each of the other commutator segments.

ARMATURE CONTINUITY TEST

MANUFACTURER'S SPECIFICATIONS          TEST RESULTS          SERVICEABLE

0-1Ω                                                                     0Ω                                Yes

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Testing Commutator:

Measure the Commutator diameter and check the mica undercut depth as necessary.

COMMUTATOR TEST

MANUFACTURER'S SPECIFICATIONS          TEST RESULTS          SERVICEABLE

Minimum diameter 28.8~31mm                              31.5mm                        Yes

Mica Undercut 0.7~1.0mm                                    0.7mm                           Yes

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Check Armature Shaft for run out:

To check for run-out, place the armature between the "v" blocks.

Turn the armature 360° while reading the dial test indicator set up on the armature core as indicated by the arrow

ARMATURE RUNOUT TEST

MANUFACTURER'S SPECIFICATIONS          TEST RESULT           SERVICEABLE

0~0.2mm                                                               0.05mm                       Yes

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Alternative Method of Testing Armature

Using 48 volt test Light

Continuity test keep one of the probes on one segment and move the other probe around each of the other segments. ( This test applies greater pressure to the windings and should be used where available) The test light should glow.

Ground test place one probe on any commutator segment and the other on either the armature core or shaft. The test light should not glow.

ARMATURE CONTINUITY AND GROUND TEST

MANUFACTURER'S SPECIFICATIONS          TEST RESULT          SERVICEABLE

Continuity Test Light on over each segment            Yes,The light on.          YES

                                                                             The commutater

                                                                             segment are connected

Ground Test Light Off                                            Yes,The light off          YES

                                                                              The commutater

                                                                              segment aren't

                                                                              connceted the armature

                                                                              cove

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Testing for internal short circuit using growler:

1. Place the armature on the "V" of the growler.

2. Turn the switch on to Growler position.

3. Hold a hacksaw blade or metal strip along the armature and rotate the armature.

ARMATURE INTERNAL SHORT TEST

MANUFACTURER'S SPECIFICATIONS          TEST RESULTS          SERVICEABLE

Hacksaw blade will vibrate when placed over         Hacksaw which means          YES

shorted winding indicating a shorted armature         shorted winding indicating

                                                                             a shorted armature 

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Field Coil and Pole Shoes

Visual Inspection- Check for signs of:

Overheating

Burning

Physical damage of insulation and coil windings

Poling

COMPONENT TEST REPORT

FIELD COILS AND             MANUFACTURER'S             TEST RESULTS             SERVICEABLE

POLE SHOES                         SPECIFICATIONS

Overheating                           Visual Inspection                       No signs                          YES

Burning                                  Visual Inspection                       No signs                          YES

Physical damage                    Visual Inspection                       There was a damage         No

                                                                                              for the field coil                      

Poling                                    Visual Inspection                       The field coil has some      YES,can be fixed 

                                                                                              damage                  

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Test the Field coils for Continuity:

Checking for continuity in the field winding place the probes on each end of the field winding

Depending on the design of starter motor circuit, field winding maybe ground or insulated from the field housing.

COMPONENT TEST REPORT

FIELD COILS          MANUFACTURER'S          TEST RESULTS          SERVICEABLE

CONTINUITY         SPECIFICATIONS

If Grounded               TEST N/A                            N/A                              N/A

Not Grounded           0~0.02Ω                              0Ω                                YES

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Test the Field coils for grounding:

Ifthe field winding to ground test can be preformed ( the field winding is not attached to the body of the starter motor). Place the positive probe on the field wire or brush, then the common probe on the body of the starter. The meter should read Infinity.

COMPONENT TEST REPORT

FIELD COILS          MANUFACTURER'S          TEST RESULTS          SERVICEABLE

GROUNDING         SPECIFICATIONS

If Grounded              0~0.02Ω                               N/A                               N/A

Not Grounded          Infinity                                   Infinity                            YES

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Brushes:

Measure the length of the brushes and inspect for cracks and other damage.

Brushes sometimes have a scribed line on one face or refer to specification sheet for allowable length.

Note: When considering the brushes for replacement, remember that the starter may not be removed from a vechicle for over 100,000Km's. If the brushes are close to the minimum you should replace. New brushes are about 14mm long.

COMPONENT TEST REPORT

BRUSHES               MANUFACTURER'S               TEST RESULTS               SERVICEABLE

                                SPECIFICATIONS

MINIMUM             5mm                                          15.9/15.9/15.9/-                 YES

LENGTH

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Brush Holder Assembly

To check for short circuit between insulated brushes and holder set the Ohms meter on the lowest resistance. Place one of the probes on the brush and the other on the metal retaining plate.

COMPONENT TEST REPORT

BRUSH HOLDER          MANUFACTURER'S          TEST RESULTS          SERVICEABLE

ASSEMBLY                  SPECIFICATIONS

Grounded Holder            0~0.02Ω                               0.1Ω                             No

Insulated Holder              Infinity                                   Infinity                           YES

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Solenoid Magnetic Switch:

Identify terminals: "B" Battery Supply, "S" ignition/ starter switch supply and "M" starter motor supply.

Note: M terminal will have a wire going into the solenoid switch

Pull in winding Test:

connect 9V power supply between S and M terminals

Note this test is done with reduced voltage and for a maximum of 5 seconds to prevent heat damage to the winding

COMPONENT TEST REPORT

PULL IN WINDING          MANUFACTURER'S          TEST RESULTS          SERVICEABLE

                                           SPECIFICATIONS

Current Draw                      8~12Amps                            9.1A                              YES

Physical Action                   The Plunger should pull in       The plunger pull in           YES

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Hold in Test

Connect 9V power supply between S and solenoid body

Note this test is done with reduced voltage and a maximum of 5 seconds to prevent heat damage to the winding

Push the plunger in by hand and then release it.

COMPONENT TEST REPORT

HOLD IN WINDING          MANUFACTURER'S          TEST RESULTS          SERVICEABLE

                                            SPECIFICATIONS

Current Draw                       5~8Amps                               10.9A                           No

Physical Action                     The Plunger should                 The plunger was            YES

                                             remain in.                               still inside

                                            When the power is                 When the power is      

                                            disconnected the plunger        disconnected the

                                            should release.                       plunger shoot out

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Pinion gear and Overruning or one way clutch:

Check pinion for gear damage and smooth movement along the armature shaft.

Turn the pinion gear in the direction of motor rotation, the clutch should free wheel and against direct of rotation it should lock.

Brushes:

To check bushes for wear, insert the end of the armature shaft into the appropriate end housing bush to and assess the shaft to bush clearance.

COMPONENT TEST REPORT

DRIVE          MANUFACTURER'S          TEST RESULTS          SERVICEABLE

                     SPECIFICATIONS

Pinion Gear   Visual Inspection                   The pinion gear is good   YES

Bushes          Visual Inspection                   Bushes was damaged      NO

Clutch           Visual Inspection                   Clytch was good             YES

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Assembly:

Re-assemble the Starter Motor:

1. Lubricate the bushes.

2. Assembly in the reverse order of dismantling.

3. Note: Align marks when assembling the shift fork and the two end housings to the field body

4. Hold the brush springs back with a steel wire in the form of book. This will enable brush to be slid on the commutator

5. Do not over tighten any through bolts and screws.

Armature Thrust Clearance:

Check Armature Thrust Clearance. Check the Clearance with seal, spring and lock plate in place.

Pinion to Collar Clearance:

Mount the starter on the  testing machine. Connect power only to S terminal. This will move the pinion out towards the collar without armature turning.

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Final no load test:

Mount the starter in a test bench, carry out no load test then enter your meter readings in the chart below.

NO LOAD TEST          MANUFACTURER'S          NO LOAD TEST RESULTS

                                     SPECIFICATIONS

Voltage                         No less than 11 volts               11.47V

Current                         30~50Amps                            46.7A

Dose the starter motor run within manufacturers specifications YES

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The no load test is good, no any problems. In testing armature, we had some physical problems with the insulation, that was damaged onto the field coil cover. In the ground circuit test, it was gread, no problems and no damages. The alternative method of testing armature also looks good, field coil and pole shoes testing we have same problem as the testing armature, it's about the field coil cover. We broken the brushes when we was doing the brushes test, but we fixed that finaly.

Battery Testing

Inspecting for battery specifications:

Make of battery: Lucds          Battery Number:X56C
Battery capacity in Cold Cranking Amps     CCA:550
Type of battery: ( Conventional, Maintenance Free, Gel Cell, Orbital, etc..)
Conventional
Can you get to the electrolyte? Yes
Explain how:  Using a 20c coin to unscrew the caps at the top of the battery.

Carry out visual checks:
Check all areas described in the above diagram for visual faults.
Are the terminals clean and tight? Yes
Does the battery show signs of swelling? ( Caused by over charging) No
Do any of the areas as described above require attention? No
What further action needs to be taken? No further action.

Check electrolyte levels:
Remove the battery cell covers (caps) and check all levels and record your findings on the chart below
Report electrolyte levels: (High, Ok, Low)

Cell           1          2          3          4          5          6 Level       OK      OK      OK      OK      OK      OK

Battery open circuit voltage (OCV) test:
Before doing the open circuit voltage test, there may be surface charge on the plates that must be removed. Surface charge voltage is excess voltage that can't be held over a period of time and is produced from charging the battery. On a vechicle surface can be removed by turning the head lights on for about a minute with the volt meter connected across the battery terminals.
The meter reading will fall and when you turn the lights off it will then start to rise.
When the meter stops rising this will be the true OCV.

Measure the terminal voltage across the battery
What range on the meter did you use? DC
What voltage result did you get? 12.60V
What is the state of charge? 95%
What voltage reading equates to 50% charged? 12.40V
Can you continue with the battery test? Yes
If battery is too discharged to load test, what further action should be taken?
The batteryshould be charged 10 hours slowly of 4 amps.
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Testing the battery electrolyte specific gravity:

Electrolyte specific gravity readings should be taken before the cells are topped up if possible. After topping up the battery, the specific gravity will be low.
To take a specific gravity readings introduce the hydrometer into the electrolyte and slowly squeezing the rubber bulb. Release the bulb slowly and watch the electrolyte rise up the tube until the float is floating. Check the colour of the fluid ( it should be clear, if it is murky it means that the plates are disintegrating; now take the reading on the float at the top level of the electrolyte ( fluid) and record your results on the chart below.

Record hydrometer test results and the colour of the fluid:

Cell               1               2               3               4               5               6
Reading     1250         1250         1250         1250         1274         1240
Colour       clear          clear          clear          clear          clear          clear
What is the specific gravity variation of your battery? 34 points

What is the allowable specific gravity variation specification of a battery? Max variation 50
Does the specific gravity vary in the cells of your battery? Pass
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High rate discharge test:
A load test should be performed to determine the battery's ability to supply cranking voltage, providing that the battery is at least 50% charged ( 12.4 volts open circuit voltage).
If less than 50% charged, then the battery should be recharged before a reliable load test can  be performed.

Note: Refer to pages 79 and 80 of Gregory's 50% of COA;minimum 9.5V. Electric's and Electronics to obtain spec's for below.

What load current are you going to apply? 275Amps.
What must the voltage hold above while load is applied? 9.5V
How long should load be applied? 10~15 second.
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Using a load tester:
When using a load tester ( high rate discharge tester)
Make sure the load control is off. On our tester turn the centre knob to decrease the load to a minimum this is off on there testers.
This can be either anti clockwise or clockwise depending on which tester you are using so refer to the machine.
Connect the positive lead to the positive terminal of the battery
Connect the negative lead to the negative terminal of the battery
Apply the specified load by turning the load control knob
Wait for the specified time and take voltage held and load current readings.
Turn off the load tester and disconnect the load tester's leads in the reverse order
Record your readings below
What was the voltage held while load is applied? 10.20V Pass
What was the load current held? 275Amps Pass
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Drain or Parasitic Draw:
When the vehicle is turned off , there should be little electricity flowing out of the battery. But if some device is still 'on', the battery may be discharged by this drain in just a couple of days. So the amps drain should be measured.
Be careful of removing the battery and losing memory in devices like radios and on-board computers. The radio may not work afterwards, or the vechicle may not run well. Try to connect the amp meter in series, without losing voltage to the systems that need to retain their memory. Or use a jumper pack to retain voltage to the systems while you connect the amp meter.

Check the amp fuse in your meter. Is it OK? It's Ok.

How did you check the fuse?
I used other meter, and put iy on Ohm then connect it to the meter being used which is on mA and checked if there is a reading in circuit.
Record radio stations in memory: not have radio stations.
Check the amp draw. Record here: 0m Amps
How many is OK？ N/A
Recheck radio stations. Was memory lost? N/A
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Battery Report:
Analyse your finding using a step process taken from the tasks that you have just performed and write them down in the area below.

What do you recommend needs to be done with this battery and system?
It's nothing needs to be done with this battery, the battery in good condition

If the terminals were corroded, how would you clean and protect them?

Sprinkle baking soda on the battery posts, the wires and the cables where ever corrosion is visible. Add water and wait a few minutes. Most of the corrosion will dissolve on contact. For remaining amounts, simply rub or brush with one of your chosen cleaning abrasives. Repeat as needed.

If the clamps or terminals are badly corroded at the battery, you can easily disconnect them. You may need pliers for this and/or wrenches to fit. Dry off the battery with a cloth to prevent splashing of the solution if you have already applied the baking soda. Disconnect the negative cable first, then the positive.

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Automotive battery testing assessment 
 Anslyse the condition of an antomotive battery
Vechicle type: Subaru
Model: Impreza          Year: 2009
Battery Number 55D23L

1. Determine the battery capacity in Cold Cranking Amps     CCA:500
2.Perform a visual check of  the battery
Report the areas that require attention? The battery looks good, no require attention
3. Determine what further action is required?
It's no action required.
4. Check electrolyte levels. (High, OK or Low)
Cell               1               2               3               4               5               6
Level           OK           OK           OK           OK           OK           OK
5. Perform an open circuit voltage ( OCV) test.
Open OCV test result? 12.7V
Interpret OCV result into state of charge as a percentage? 100%
Specify the voltage at which you can continue with the battery test?
Specified voltage           12.4V
6. Determine what further action should be taken at this point?
Nothing to do with the battery.
7. Perform specific gravity tests on all cells and report on the visual condition of the electrolyte?
Cell               1               2               3               4               5               6
Reading      1275         1275         1275         1265         1260         1250
Colour        clear          clear          clear         clear          clear          clear
What is the specific gravity variation of your battery? 25
What is the allowable specific gravity variation? 50
8. Perform a high rate discharge test.
Determine the load current to apply? 250A
Specify the voltage that the battery must hold above while load is applied? 9.5V
How long should load be applied? 10~15 seconed
9. Record your test results below
What was the voltage held while load is applied?
What was the load current held?
( When I did the test I can't remember the load current to apply and the voltage that the battery must hold above while load is applied so I was not allowed to do the test)
10. Analyse all of your results and document your findings and recommendations.
The battery looks good and the open circuit voltage test result in good condition, don't to be charged. The gravity variation of the battery was also good.

Electricity Circuits: Individual, Series, Parallel and Series-Parallel

Available Voltage= vs. Voltage Drop=vd:

When you are asked measure the "Available Voltage/Supply Voltage" it means you take the common lead(black or "-") of the voltmeter attached to a good earth (ground or "-"). The positive lead (red or "+") of the voltmeter is attached to the point you want to measure. As shown in the circuit diagram below.

When you are asked to take a "Voltage Drop" measurement , it means you have the meter leads on either side of component you are measuring. For instance, if you are measuring voltage drop across a light bulb, the red lead will be touching the wire coming from the positive at the light bulb, and the black lead will be touching the wire to the negative side of the light bulb. As shown in the diagram below.

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Measuring amps (current) flowing through the circuit:

To use a multimeter to measure the amperage flowing through a circuit you will need to move the positive lead (the red lead) into a different position on your meter. Take the positive out of the meter and refit in the DC amp position. There are some times 2 amp position 1 for milliamps and the other normally 10 or 20 amps

Now set your meter to the DC amp position and wire the meter in Series as shown in the diagram below. The (red) positive (+) lead goes to where the conventional current comung from and the (black) the negative (-) lead goes to the path to the negative also called earth or common.

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Measure the Available Voltage in the circuit at these points:

Using a voltmeter measure the (supply) available voltage at he different points and list below:
The positive 12V supply (B+)                    12.72V
Terminal before the switch                         12.69V
Terminal after the switch                            12.62V
Terminal before the light bulb                     12.61V
Terminal after the light bulb                        0V
The negative on the 12V supply (N-)         0V

Explain what happens to the voltage. If the voltage at the battery is 'available to do work', what happen to it as it progresses through different components of the circuit?
The  voltage drop when the voltage progresses through different components of the circuit. The voltage drop was different, it's depend the components.
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Measure the Voltage Drop across the circuit parts:

Using a voltmeter measure the voltage drop across the different components of the circuit and list below:
From the B+ of the 12V supply to the input of the switch     0.03Vd
From the input of the switch to the output of the switch        0.03Vd
From the output of the switch to the input of the bulb           0.00Vd
From the input to the bulb to the output of the bulb              12.62Vd
From the output of the bulb to the N- of the 12V supply      0.00Vd

Which component tested has the largest voltage drop. Explain why the voltage drop is so large.
From the input to the bulb to the output of the bulb tested has the largest voltage drop, because it's got more consumer than another.
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Measure the amps (current) flowing through the circuit:

Remember the amp meter must be connected inseries. Record how many amps you find flowing through these points:
Wire before light bulb                    0.34A
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Caculate the resistance of the light bulb:

You have measured the voltage and the amps. In the box below, calculate the resistance of the light bulb using Ohm Law.
Ohm Law：V=I*R;I=V/R;R=V/I
R=V/I               I=0.34A     V=12.70V
R=12.70/0.34=37.35Ω
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Calculate Watts used at the light bulb:

You have measure the voltage and the amps. In the box below, calculate the watts used at the light bulb using the Power Triangle.
Power Law:  W=V*I;I=W/V;V=W/I
W=I*V             I=0.34A     V=12.62V
W=0.34*12.62=4.29w
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Create a circuit with a larger light bulb:

Using the battery or power supply, light bulb, switch, wires, and create a complete circuit for electricity to flow then turn the switch "on".
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Measure the Voltage Drop across the circuit parts:

Using a voltmeter measure the Voltage Drop across the different components of the circuit and list below:
Wire before the switch                    0.1Vd
Switch                                            0.1Vd
Wire before light bulb                     0.05Vd
Light bulb                                       12.38Vd
Wire after light bulb                        0.05Vd
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Measure the amps (current) flowing through the circuit:

Measure the current flow through any part of the citcuit; remember the amp meter must be connected in series. Rcord your findings below:
Current flow through circuit            1.8amps

Make up a statement about what you can see happening to the amperage in this circuit compared with that with the small bulb?
The big bulb used more current than the small bulb.
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Calculate the resistance of the light bulb:

Calculate the resistance of the larger light bulb using Ohm Law.
R=V/I               V=12.38V     I=1.8A
R=12.38/1.8=6.87Ω
What does the resistance tell you about how current flow is affected through thecircuit when you compared with this result against the same calculation for the small bulb?
The resistance tell me the larger light bulb used less resistance and more current than the small bulb.

Calculate Watts used at the light bulb:

You have measured the voltage and the amps. In the box below, calculate the watts used at the light bulb using the Power Triangle.
W=I*V             V=12.38V     I =1.8A
W=12.38*1.8=22.28W
What does the watt tell you about the brightness of the light bulb compared with the result of the same calculation with the small bulb?
The big bulb was more brightness than the small bulb with the result of the same calculation with the small bulb, and the big used mor watt than the small one.
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Series Circuit:

Create a circuit with two light bulbs in series:

Use the same bulbs and make a circuit like before, but this time have the two light bulbs, one after another. There should be only one path for electricity to flow through, and it should flow first through one light bulb, then the other. Use the diagram below to help you design the circuit.

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Measure Voltage Drop across the components:

Using a voltmeter measure the voltage drop across the different parts and list below:
Wire before the switch                    0.01V
Switch                                            0.03V
Wire before light bulb 1                  0.02V
Light bulb 1                                    6.13V
Wire between light bulb 1&2          0V
Light bulb 2                                    6.30V
Wire after light bulb 2                     0V

Measure the voltage available at the battery     12.7V
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Explain what happens to the voltage in the different compoments in this circuit?
The different components gets different voltage. The voltage drop from wire before the switch was 0.01V to switch was 0.03V, and a hurge voltage drop after bulb1 and bulb2, because they shared the same supply voltage.
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Measure amps in the circuit:

Use an amp meter to measure the amps at different parts of the circuit.
Record how many amps you find at these points:
Wire before the switch                    0.22A
Wire before light bulb 1                  0.22A
Wire between light bulb 1&2           0.22A
Wire after light bulb 2                     0.22A

How is the amperage different from the amperage the individual circuit?
What is happening to the amps in this circuit if you compare it with the amps of both the individual circuit?What is going on and why?
In the individual circuit, it has one consumer and used supply voltage
In this circuit, the amps lesser than individual circuit, because in this circuit has two consumer to shared the same supply voltage.
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Calculate the total resistance of the circuit:

You have measured the voltage and the amps. In the box below, calculate the resistance of the circuit.(Using Ohm Law)
R=V/I     V=12.7V;I=0.22A
R=12.7/0.22=57.73Ω

Calculate Watts used by each light bulb:

Since you have measured volts drops and amps, you can calculate watts. In the box below, calculate the watts used at each light bulb. (Using the Power Law)
W=I*V     I=0.22A;V=6.13V
                 I=0.22A;V=6.3V
W=0.22*6.13=1.35W
W=0.22*6.3=1.39W

What do the watts caculated tell you about the brightness of the light bulbs in this series circuit and why has it happend?
In this series circuit, both of the bulbs used same wattage and the brightness is more darker than the small one,because both of the bulbs shared the same supply voltage.
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Create a circuit with three light bulbs in series:

Use the same bulbs and make a circuit like before, but add a third bulb, all one after another. There should be only one path for electricity to flow in, and it should flow first through one light bulb, then the next, then the last.

Measure Voltage Drop across the parts:

Using the voltmeter measure the voltage drop across the different components and list below:
Wire before the switch                    0V
Switch                                            0.82V
Wire before light bulb 1                   0V
Light bulb 1                                    3.79V
Wire between light bulb 1&2           0V
Light bulb 2                                    3.81V
Wire between light bulb 2&3          0V
Light bulb 3                                    4.34V
Wire after light bulb 3                     0V
Measure the voltage available at the supply     12.71V

Explain what happens to the voltage:

What happened to the voltage drop caross the different components in this circuit when you compare it with the two bulb series circuit? Take special note of what happens to the voltage drop across the bulb, what has happened and why?
There are three main voltage drop in light bulb 1, bulb 2, bulb 3 at 3.79V, 3.81V and 4.31V respectively. The values of the voltage drop in the three bulbs are smaller than the two bulbs, because one bulb was added in three series circuit. In addition, the switch has a noticeable voltage drop which produces the resistance due to heating.
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Measure amps in the circuit:

Use an amp meter to measure the amps at different parts of the circuit. Record how many amps you find at these points: (remember amps have to be measured in series.)

Wire before the switch                    0.18A
Wire before light bulb 1                   0.18A
Wire between light bulb 1 &2          0.18A
Wire between light bulb 2 &3          0.18A
Wire after light bulb 3                      0.18A

Explain what happens to the amperage?

What is happening to the amps in the circuit? How does this amp measurement differ from the two bulb series circuit? What is going on?
All the amps in this circuit are same. In this circuit use three bulbs and the amps lower than the two bulbs series circuit. The smallest bulb still going on but the brightness was more dark than two bulbs series circuit.

Calculate the total resistance of the circuit: You have measured the voltage and the amps. In the box below, calculate the resistance of the circuit. (Using Ohms Law)
R=V/I     V=12.71V;I=0.18A
R=12.71/0.18=70.61Ω

Calculate Watts used at each light bulb:
In the box below, calculate the watts used at each of the light bulbs. (Using the Power Law)
W=V*I     V1=3.79V;V2=3.81V;V3=4.34V;I=0.18A
W1=3.79*0.18=0.682W
W2=3.81*0.18=0.686W
W3=4.34*0.18=0.781W

What does this tell you about the brightness of the light bulbs compared with the two bulb series circuit?
In this series circuit, all of the bulbs use similar wattage, but it was lower than the two bulbs series circuit, and the brightness was more darker than the two bulbs series circuit, because all of the bulbs shared the same supply voltage likes the two bulbs series circuit.
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Use the "available voltage" method to measure voltage in the circuit:

Starting at the positive side of the battery, measure available voltage at the different parts of the circuit. Record the readings below:

Measure the voltage available at the:
Battery positive                    12.71V
Input to the switch                12.71V
Output of the switch             11.80V (something wrong with switch)
Supply to light bulb 1            11.79V
Output of light bulb 1           7.94V
Input to light bulb 2              7.84V
Output of light bulb 2           4.12V
Input to light bulb 3              4.12V
Output of light 3                      0V
At the negative of the supply    0V

Explain what the different reading are telling you when using Voltage Drop compared with Available Voltage:
The voltage drop show me how much voltage was used of each componet, for example: switch used 0.82V, light bulb 1 used 3.79V, light bulb 2 used 3.81V, light bulb 3 used 4.34V. The available voltage show me how much voltage can be used after each componer, for example: after battery positive 12.71V can be used, after Input to the switch 12.70V can be used, after output of the switch 11.80V can be used, etc.
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Parallel Circuits:

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Measure the available voltage at each light bulb in the parallel circuit and record below:

Light bulb 1                    12.64V
Light bulb 2                    12.64V
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Measure voltage drop across each light bulb in the parallel circuit and record below:

Light bulb 1                    12.57Vd
Light bulb 2                    12.63Vd

Describe what happens to the volts in the parallel circuit (What rule of electricity applies here and how is it different from a series circuit.)
The available voltage at each light bulb were same. The voltage drop across each light bulb were similar and bigger than series circuit. In this circuit each consumer therefore has own input and output and used same supply voltage, but in series circuit each consumer shared the same supply voltage.
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Measure the current flow （amps) through the parallel circuit with the two light bulbs using an amp meter and record:

Current flow through light bulb 1 circuit 0.34 Amps
Current flow through light bulb 2 circuit 0.33 Amps
Total current flow through both circuit   0.67 Amps

Describe what happens to the amps in the parallel circuit. (What rule of electricity applies here and how is it different from a series circuit.)
The current flow through light bulb 1 and 2 at 0.34A & 0.33A each and the current was divided by each bulbs in this parallel circuit, but in the series circuit, the amps were all same values any steps.
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Calculate the total resistance of each bulb in the circuit:

R=V/I     V1=12.57V;V2=12.63V;I1=0.34A;I2=0.33A
R1=12.57/0.34=36.97Ω
R2=12.63/0.33=38.27Ω

Calculate the total resistance of the circuit using the following formula:

Show the full working in the box below 1/Rt=1/R1+1/R2
1/Rt=1/R1+1/R2     R1=36.97Ω；R2=38.27Ω
1/Rt=1/36.97+1/38.27
Rt=18.8Ω
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Calculate total watts used in the parallel circuit while both lights are on:

W=V*I     V=12.70V;I=0.67A
W=12.7*0.67=8.51W

Calculate watts for each indibidual bulb

W=V*I     V1=12.57V;V2=12.63V;I1=0.34A;I2=0.33A
W1=12.57*0.34=4.27W
W2=12.63*0.33=4.17W

How does these watts compare with watts used when the bulbs were in series? Why has this happened?
In the parallel circuit, these watts higher than the watts used when the bulbs were in series because in the series circuit the voltage drop value were lower than parallel circuit value and the current value in the series circuit also lower than parallel circuit's value.
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Create a parallel circuit that now has 3 lights bulbs:

Now measure the current (amps) flow through each of the 3 lights bulbs circuit, using an amp meter and record:

Current flow through light bulb 1 circuit 0.34Amps
Current flow through light bulb 2 circuit 0.34Amps
Current flow through light bulb 3 circuir 0.32Amps
Total current flow through all the circuit 1 Amps

What happened to the total amps flowing through the circuit when the third light bulb was added? (Did the current flow through each of the other light bulbs change? If so why?
The current flow didn't through each of the othe light bulbs change, when the third light bulb was added, because the third light bulb used same supply voltage, it doesn't need to share the supply voltage from other light bulbs.

What rule or concept does this show about amps in a parallel circuit?
In a parallel circuit each consumer has its own input and output so when we added more consumer, the amp for each consumer never be changed.Current draw for this circuit is high!
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Measure the available volts in the circuit now that there are 3 light bulbs in the circuit and record:

Light bulb 1                    12.63V
Light bulb 2                    12.63V
Light bulb 3                    12.63V

Measure the voltage drop across each of the lights now that there are three light bulbs in the circuit

Light bulb 1                    12.61Vd
Light bulb 2                    12.61Vd
Light bulb 3                    12.60Vd

What hanppened to the available voltage in the circuit when the third light bulb was added? Why did this happen?
The available voltage in the circuit didn't has any change when the third bulb was added, because the third light bulb has its own input and output and without share the supply voltage.

What happened to the voltage drops in the circuit when the third light bulb was added? Why did this happen?
The voltage drops in the circuit was similar when the third light bulb was added. In parallel circuit each consumer has its own input and output,  depending on the number of electrical consumer.
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Calculate the resistance of each bulb:

R=V/I     V1=12.61V;V2=12.61V;V3=12.60V;I1=0.34A;I2=0.34A;I3=0.32A
R1=12.61/0.34=37.09Ω
R2=12.61/0.34=37.09Ω
R3=12.60/0.32=39.38Ω

Calculate the total resistance of the circuit using the following formula:

1/Rt=1/R1+1/R2+1/R3     R1=37.09Ω;R2=37.09Ω;R3=39.38Ω
1/Rt=1/37.09+1/37.09+1/39.38
Rt=12.61Ω

Calculate total watts used in the parallel circuit with three lights working or "on"
W=V*I     v=12.68V;I=1A
W=12.68*1=12.68W

Logic Probe Construction

Wiring Diagarm:

Logic Probe Parts List:
Red LED:Black 2.4mm diameter,about 300mm long
Green LED:Red 6.4mm diameter,about 175mm long
Black wire 2 meters long:Black 12.7mm diameter,about 125mm long
Red wire 2 meter long
2 resistors 1KΩ
Red alligator clip
Black alligator clip
100mm plastic tube 7mm ld
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Wiring Diagram:

The wiring diagram looks like this:

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Soldering the parts:

The LED's, 1KΩ resistors,and wires are then soldered together to look like the picture blow.

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Insulation of resistors:

Using the small heat shrink insulate both resistors and LED legs,(from the black and red wires to as close as possible to the LED) see picture below.
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Brass rod:

Using the correct safety equipment and grind a point on one end of the brass rod then insulated with heat shrink for 60mm starting 10mm from the point, leave a 10mm gap and fit a 75mm heat shrink of the same diameter so it insulates the blunt end of the rod as shown in the picture belows.

Tin the gap between the two pieces of brass rod; this will make it easier to solder the LED legs on later.

Before soldering the uninsulated legs of LED's to the brass rod, cut two 15mm pieces of the blue heat shrink and slide them both over the red and black wries and up onto the rod, get the LED's into approximately the correct position then heat the heat shrink. This will support the weight of the wires and prevent the insulated legs of the LED's breaking off.

Position the LED's to sit just above the rod, making sure that the insulation protects the insulated legs of the LED's from the brass rod. Twist the uninsulated legs of the LED's individually around the brass rod and solder to the tined section as shown in the picture above.

Before continuing, use the Hot Glue gun and glue under the LED's to give them extra support.

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Fitting the plastic support tube:

Select the 100mm length of 10mm diameter plastic tube and cut a groove out of one end. This groove needs to be as long as the two LED's are in line, pluse 5mm that when fitted will extend past the LED's as shown in the pictures below

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Improving the appearance:

To improve the appearance cut the 20mm length of  the 10mm black Heat Shrink. Slide it on from the pointed end of the brass rod. It may be necessary to squeeze the plastic tube together so the heat shrink will side right up close to the green LED. Now carefully heat the Heat Shrink evenly all the way around until it won't get any smaller.(It won't pull down tightly on the brass rod at this point).

Next cut a 90mm length of the 10mm black Heat Shrink and slide over the wires up onto the other end of the plastic tubing and heat shrink as above.(Refer picture below).

Cut 20mm lengths of red heat shrink and fit to both ends of the probe, this will pull the black Heat Shrink onto the brass rod and the wire tightly.
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Twisting and securing wires:

Twist the wires neatly and fit 15mm lengths of the red heat shrink every 500mm along the wires. Don't twist last 300mm of the wire as Alligator clips need to be attached to the ends of the wires.(Refer picture below)

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Fitting Alligator clips:

Remove the plastic covers from both the clips and install the correct way around on the appropriate coloured wires. Strip the insulation and twist about 10mm of each wire tightly. Insert the twisted end of the wire through the claws provided. Cut off the excess twisted wire and solder joints.

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Refitting Alligator clip covers:

To refit an Alligator clip cover it is helpful if you squeeze the clip wide open and make the jaws grip onto a screw drive, then slide the cover into place and release the screw driver from the jaws. Repeat on the other Alligator clip.

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Testing:

This tester is only for 24 volts or less, DC volts only. Connect the red clip to battery positive and the black clip to battery earth(negative). Both red and green LEDs will light. This tests the connections and that the tester is properly connected. Now touch the brass probe end to the positive battery terminal and the green LED goes out, and the red LED gets brighter. Touch the probe to the earth battery terminal and the red LED goes out, and the green LED gets brighter.

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Questions:
1.Why do both the red LED and the green LED go when you connect to the battery?
When I connect to the battery the current come through the red LED to green LED to the end of negative, so both the red LED and the green LED go.

2. Why does the green LED go out when the probe contacts the battery positive?
When the probe contacts the battery positive, the current come through the brass rod, but can't go through the green LED, because the green LED is one way to pass the current, so the green LED goes out.

3.Why does the red LED get brighter when the probe contacts the battery positive?
When the probe contacts the battery positive, the current come through the brass rod to the red LED to the negative, so the red LED get brighter.