Compound circuits

Not much was done with the Compound circuits as it was a combination of parallel and series and since weve already learnt about those, it was pretty self explanitary on what was going to happen with this circuit.

This image was sourced from google. (this image apparantly came off someone else's blog)

 

The parallel part of the circuit would keep the current of the parallel bulbs operating at a equal brightness while the series part of the circuit would have the bulb operating at little to no voltage drop but will consume all of the available voltage.

parallel circuits

A parallel circuit is a very power efficient type of circuit.
All consumers will take all the available voltage equally if connected in a parallel circuit.

The circuit has the same componants as any other circuit (powersource, bulbs, wiring etc), but instead of being connected in series (one after the other) the componants (or bulbs in this case) are connected in parallel (hence parallel circuit). Here is a picture to show you what i mean by connected in parallel.

If the bulbs are connected in parallel they will have the same voltage across all ends as the current will comeback together in the end.

The Parallel circuit was assembled and put to the test.
The switch on the circuit was turned on and the result was that all 3 bulbs glowed with the same brightness.
Rather than in a series circuit were each bulb would get dimmer 1 after the other, the parallel circuit however will have all bulbs glowing with the same brightness (as said before).

relays

Ahh Relays...the hardest of all the circuit componants...well i thought it was.

A relay could be thought of as a magnetic switch, were a low amp circuit to switch on a higher amp circuit.
The Relay will have a coil of wire inside that will create a magnetic field when the circuit has power.
The second circuit in the relay will be a switch that when the first circuit is on, the magnetism will pull the switch in the second circuit on, completing the relay and turning on whatever component it is connected to.

We learned how these worked by testing them on lights.
We made up a circuit that involved the Relay component, then added bulbs to the circuit.
Turning in one switch on the circuit made the 2 out of 3 bulbs glow and the second switch on the circuit made all three glow brightly...the relay was working.

Diodes

Diodes were an interesting type of circuit componant.

I already knew a bit about them which helped me a bit through the subject.

Diodes are an electrical componant that stops power surges or just basic current flow from flowing back from its source.
Diodes only allow current flow go one way and this prevents surges stopping any electrical device to short out from Backflow.

Thats basically all i can say about Diodes as thats all they do.

The way I learnt this about Diodes this time was that the class told to make a Logic probe.

We had 2 LED's (light emitting diodes) Some wires, some heat-shrink, a brass rod, 2 resistors, 2 alligator clips and a plastic tube for insulation.

we soldered the LED's on the wires, one wire per LED and insulated some contacts on the brass rod with heat shrink the resistors were soldered onto the wires and the wires were soldered onto the brass rod. the alligator clips were attached to the other ends of the wires and then we were done. (A brief explanation on the build but you get the jist of it)

we tested the Logic probes on powered volt meters to see if they worked, thus they did, when theres a positive power source the logic probe lights up green and negative lights red.

Series Circuit

My next lesson was learning about a series circuit and how its worked.

The series circuit is very similar and almost identical to the individual circuit but involves attaching 2 or more bulbs onto the circuit.

The components needed are the same as that of the individual circuit (bulb/s, switch, fuse, power supply and nessesary wiring).

A series circuit works the same way as a individual circuit but with added bulbs or consumers.
The bulbs/consumers act as a resistor and consume the voltage as it goes through the circuit soaking up power from consumer to consumer but as it travels through the bulbs (for example) each one, one after the other will get from the resulting voltage drop.

Starter motors

We started off by our normal safety procedure, overalls etc.
we needed our tools, mainly screwdrivers and sockets, then we got started.

We were given a starter motor and was told to find a problem (later revealed it had no problem, but to teach us how to find out it didnt).it was tested on a test bench where the operator made it look like it had a problem so then we could investigate.

We started by taking the starter completly apart so then we could test and examine all the individual parts.
from solenoid to commemtator and brush plate, etc.
to disassemble we removed the M terminal wire from the solenoid, removed screws from the commutator housing, removed the commutator housing, removed the brushes aswell as the brush plate, removed the armature, etc.

First was the visual inspection on the armature, there was no overheating, no burning, no physical damage and a little it of poling...by little i mean tiny suface scratches.

next test was ground testing the windings with a multi meter, the reading must read (infinity) as there is no circuit between the winding and the ground, if there is a connection to earth, the winding needs to be replaced or re-wound.

next test, continuity circuit test.
using the multi meter set to ohms, check each commutator segment with 1 probe on 1 segment and dragging the other probe around the rest of the segments. test result was 0.0001Ohms - serviceable.

next test, measuring commutator diameter.
taking a vernier caliper to measure, we measured the diameter of the commutator, result: 31mm.
26.8-31mm being the manufacturer'a specs.

next test, the growler test
placing the armature onto the growler machine and rotating the armature 360degrees whilst lightly balancing  a hacksaw blade upon the top. If the hacksaw blade starts to chatter along the armature during rotation on the growler, there is a short circuit along the armature segments. Result: no chatter-serviceable

next the brushes were examined.
The brushes was measured and were at a serviceable length.
a quick visual examination shows they were also in good condition.

next the solenoid magnetic switch was tested.
Terminals: B-battery power, S-ignition/starter switch supply and M-Starter motor supply.
A 9V power supply was hooked up to its terminals, it drew a current of 25Amps and the solenoid plunger pulled in...operated as it should.

after a long session of testing, i come to the last test of the starter, checking the pinion gear and clutch.
the pinion gear has little to no wear and tear, the bushes are in good condition and has little "play" and the one-way clutch operates as it should.

Q and A

1.To turn the engine enabling it to start.

2. 1-Armature
    2-Field coils and pole shoes
    3-Housing
    4-Brushes
    5-Bushes
    6-starter drive

3.clockwise

4. 1-inertia
    2-pre-engaged
    3-gear-reduction

5.

6. Front view of a starter motor clutch.

 

7. The pinion is turning in direction of the arrow 

at a speed higher than it should go when the engine has started.

the clutch allows it co compensate briefly and safely pull away.

8. Series wound starter internal circuit.

9. Designed for low compression motors, produces high torque on low revs and low torque on high revs (vice versa).

10.