CP Fitters' Phase 2 Apprenticeship Training

Low friction bearing used to support radial loads in automotive applications.

This is a spring loaded ball and socket joint used mostly in the steering systems of plant vehicles. The joint allows a range of movement between the various rods and linkages that make up the steering system.

If the ball joints are fitted to the track control rod, they may be called 'track control rod ends'. These have the same basic construction as the ball joint, they are just named differently because of where they are used.

Read more here on ball joints and check out the overall layout of the steering system here.

From the company website:

Established in 1958, BAM Civil (formerly Ascon), is the largest civil engineering and public works contractor in Ireland.

BAM Civil prides itself on delivering quality projects safely, on time and within budget. Innovative solutions, engineering ingenuity, adherence to the highest safety and quality standards and professional construction management are the hallmarks of BAM contracts. Read More...

Company Contact: Adrienne Bryan

Apprentices: Kevin Cross (g1cp13a)

A bar is a measure of pressure.

1 bar = 100 kPa, or

1 bar = 100,000 Pascals.

The conversion factor to the Imperial way of measuring pressure is 14.5

In other words to convert bar to psi (pounds per square inch), multiply by 14.5.

Example: Convert 2 bar to psi.
Answer = 2x14.5 =29 psi.

Although bar and atmospheres (atm) are very similar ways to measure pressure, they are not the same:

1 bar = 100 kN/m2 = 14.5 psi

1 atm = 101.3 kN/m2 = 14.7 psi

Company Contact for Reel-Tech

Telephone: 01 8015871; Mobile:087 6388955

Apprentices:

• James Hayes (g1cp13a)
  

In the SI, there are 7 base units of measurement. The ones we come across in the phase 2 course are:

• s, seconds, for time
• m, metres, for distance
• K, kelvin, for thermodynamic temperature
• kg, kilogramme, for mass
• A, ampere, for units of electrical current

Other units of measurement such as those for torque, speed, power etc. are all based on SI units of measurement, so they are said to be 'base derived' units of measurement.

A base limiting resistor is inserted into an electronic circuit in order to protect the delicate base/emitter circuit of a transistor. Unlike the more robust collector/emitter, the base/emitter circuit cannot pass large currents, it can only pass small currents. The transistor works by taking the small base/emitter current and amplifying it-allowing a much larger collector emitter current to flow.

In order to limit the current flowing into the base of a transistor, we fit a resistor in series into the circuit. This has the effect of limiting the current flowing into the base/emitter circuit of the transistor.

Note:-
Transistors need not always have a base limiting resistor fitted. Sometimes the incoming current (or signal) is so small that there is no danger to the transistor. In these cases, the function of the transistor is usually to amplify the signal so that it can be used by other parts of the electronic system.

In DC electricity, a single source of that energy is known as a cell.

When we join cells together in series, parallel or series parallel, we then have a battery of cells, or just simply a battery.

A hydrometer is an instrument for measuring the density of a liquid relative to that of water.

During your phase 2 course, you will use hydrometers on two occassions:

1. Measuring the relative density of battery electrolyte, in order to check the state of charge of the battery.
2. Measuring the relative density of engine coolant, in order to check the concentration of anti-freeze in the coolant.

On the right we can see an actual hydrometer. It is a floating device. The denser the liquid, the higher it will float, and give a reading of the liquid density on its graduated stem.

The instrument is basically a glass tube with lead shot at one end and a graduated scale at the other.

The instrument is used to compare the density of whatever liquid it is immersed in to the density of water. Water is said to have a density of one, so the electrolyte from a fully charged battery would be 28% more dense-1.28.

Functions, Operation and Use of the Hydrometer:

The hydrometer is used in plant vehicle electrics to measure the density of battery electrolyte compared to that of water. Battery electrolyte in a fully charged battery is about 25% more dense than water. We can use the hydrometer to measure the density of the battery electrolyte compared to that of water. This reading is dependent on the ambient temperature, and the following figures are for a temperature of 250C: Fully charged battery: 1.28 Half charged battery: 1.2 Discharged battery: 1.1

Fully charged battery: 1.28 Half charged battery: 1.2 Discharged battery: 1.1

Using the hydrometer:

Always use safety glasses or a full face mask when working with batteries and electrolyte. Make use also of the acid proof gloves and aprons provided. If you get battery acid on your skin or in your eyes, flush immediately with copious amounts of water. If pain and discomfort persist, seek medical assistance. Check here for emergency procedures.

Go to each cell in turn. Agitate the electrolyte in the cell. Then take the electrolyte into the instrument. If any of the battery plate active material has broken away, the electrolyte will be discoloured, so make sure the electrolyte is clear.

Induce enough electrolyte into the instrument to ensure the hydrometer is fully afloat. Be careful not to induce too much electrolyte, as it would cause the hydrometer to rise too much and strike the top of the instrument, giving you a false reading. Make sure the hydrometer is fully and freely afloat.

Read off on the scale provided to see the relative density of the elctrolyte.

During the induction phase of the course, you will be issued (at your own expense) with a battery hydrometer.