Glossary of terms you will come across during your Phase 2 training.
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> means greater than -example 2 > 1

< means less than - example 1 < 2

≤ means less than or equal to.

≥ means greater than or equal to.

 Keyword(s): ≤<≥
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Lambda, a letter from the Greek alpahbet. In automotive engineering, it is used to represent the stoichiometric ratio of the amount of air required to burn a fuel. For example, for diesel, the value is approximately 14.5:1, meaning that it takes 14.5 parts of air to burn 1 part of diesel.

The stoichiometric ratio for petrol is approximately 14.7:1.

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Pi, Greek letter used to represent how many times the diameter of a given circle will fit into its circumference. This is constant at 3.142. Apprentice cp fitters use this figure for many calculations, for example: when calculating the capacity of an engine; when calculating centrifugal force and when calculating the peripheral speed of a cutting disk.

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This is a Perkins designation, and refers to the 1100 series engine. The '4' refers to a four cylinder engine, and the 'D' refers to the common rail engine.

This engine has full electronic control of the fuel system - common rail with electronic injectors.

As of April, 2012, we operate 3 of these engines.

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This designation refers to the 1100 series Perkins engine. The '6' refers to the number of cylinders, and the 'C' refers to the fuel injection system, which is mechanical, based around a rotary fuel injection pump. This engine is the forerunner of the 1100D common-rail engine. Currently, the section is equipped with 6 1106C engines and 3 1104D engines.

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During the electrical module, one of the suggested exercises is to construct various electrical circuits such as parking lamps, headlamps (including relays) and glow plug circuits (including solenoid control).

In order to facilitate this exercise, we use 12V electrical training boards. These are boards of steel construction, with a working tray and a base that can accommodate a 12V battery.

This set up allows apprentices to construct the various circuits, and connect the board to an engine fitted with an alternator.

This set up allows each apprentice to wire up all the basic electrical circuits and components found in a typical plant vehicle.

 Keyword(s): 12V electrical training boards
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This consists of a 12V lamp, with two different terminals. One terminal (the earth terminal) consists of a short cable and a crocodile clip. The other terminal is at the pointed end of the tool. It is used by fastening the crocodile clip to a good earth point, and then using the sharp end of the took to probe wires. If the wires are live, the lamp will glow.

During the induction phase of the course, you will be issued (at your own expense) with a 12V test lamp.

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CAUTION: Li-ion batteries do not behave the same way as lead acid batteries do, when they are being charged and discharged.
Make sure you know how these batteries operate, how they are charged and how you can safely use and discharge them.
If this type of battery is mis-handled or abused in any way (physically damaged), there is an immediate and great risk of fire or explosion.

The number '18650' describes a battery, similar in size to an AA battery.

An 18650 is a lithium ion rechargeable battery. The correct name is “18650 cell”.

The 18650 cell has voltage of 3.7v and a capacity of between 1800mAh and 3500mAh.

The cell name is based on its dimensions: the cell is 18mm in diameter and 65mm in length.

For comparison purposes, an AA cell is a 14500 cell - 14mm in diameter and 50mm in length

 Keyword(s): lithium ionlithium-ionLi-ion
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One of a series of diodes (the 1N4000 series). They are popular, 1 amp, general purpose, silicon rectifier diodes.

During the Phase 2 course, we use these diodes to make half-wave rectifiers, full-wave rectifiers, and to suppress voltage spiking on 30 amp relays in circuits such as the time-delay circuit built as part of the Electrical Module.

 Keyword(s): 1N4001

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Crow's foot tool that allows you to tighten injector pipe unions with a 3/8" torque wrench.
 Keyword(s): 276-1216

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### 3 Effects of electricity:

1. Chemical change  - For example, the electrolyte in a battery changes from sulphuric acid (H2SO4) when the battery is charged, to water, H2O, when the battery is discharged.
2. Heat - For example, current passed through a bulb causes the filament to glow white hot. This is incandescent heat.
3. Magnetism - for example, when we pass electrical current through the commutator and the field windings of a motor, like poles come into close proximity. These poles repel each other, giving us the motoring action.
 Keyword(s): three effects of electricity
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Injector clamp bolt.
 Keyword(s): Injector clamp bolt

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Also written as 50 Hz or 50Hz.

This is the frequency at which mains electricity in Ireland is delivered at.

We know that in an AC circuit, rather than flow constantly in one direction, the electrons move rapidly back and forth. The rate at which these electrons move back and forth is referred to as the frequency of the supply. In Ireland, the mains AC supply has a frequency of 50 Hz. In other words, the electrons in our homes move back and forth in the wires 50 times every second when a circuit is closed.

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The 555 Timer IC is an integrated circuit (chip) implementing a variety of timer and multivibrator applications. The IC was designed by Hans R. Camenzind in 1970 and brought to market in 1971 by Signetics (later acquired by Philips). The original name was the SE555 (metal can)/NE555 (plastic DIP) and the part was described as "The IC Time Machine". It has been claimed that the 555 gets its name from the three 5-kohm resistors used in typical early implementations, but Hanz Camenzind has stated that the number was arbitrary. The part is still in wide use, thanks to its ease of use, low price and good stability. Read more...

 Keyword(s): 555 chips

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This is a hard covered folder for holding any course notes you may write up, and for any diagrams you may draw.

It is important to get into the habit of writing up your notes on a regular basis. To that end, you are supplied with a spiral notebook and black and red pens. During induction, you will also purchase a geometry set and a pack of markers.

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During your phase 2 training, it is important that you take and write good notes on the course material. You should also get used to drawing detailed diagrams of vehicle and machine components.

In order to help you do this, you will be issued, free of charge, a spiral notebook and an A4 refill pad. As you fill these pads and notebooks, you will be given new replacement items, also free of charge.

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This is a qualification awarded by the Institute of the Motor Industry.

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Anti blockier system, or anti-lock braking system, an electronically controlled system that senses the relative speeds of road wheels in order to determine whether braking wheels have locked up and began to skid. If they have, the system overrides the braking effort supplied by the driver, and frees the brakes until the wheel begins to turn again (stop skidding).

The system is informed by speed sensors at the wheels. These same sensors can be used to feed into a traction control system.

 Keyword(s): Anti-lock brakingAnti-lock brakesantilock brakingantilock brakes
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Absolute zero is, by definition, the lowest temperature that can be reached.

In relation to measuring temperatures, for everyday use, we use degrees centigrade, oC.

However, in engineering and science, this scale of measurement is insufficient.

We know that with thermodynamic temperature, the lowest temperature we can reach is -273oC. We call this absolute zero - you cannot get a temperature any lower.

We call this lowest possible temperature 0 on the Kelvin scale. On this scale, water freezes at 273K (0oC) and boils at 373K (100oC). The lowest possible temperature on the Kelvin scale is 0 Kelvin

 Keyword(s): absolute units
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In relation to three stage battery charging and the constant current (cc), or bulk charge stage, the level of charge that can be applied without overheating the battery is known as the battery's natural absorption rate.

It is best to keep the maximum voltage at around 14.3V for this stage.
This stage of charging can return the battery to 80-90% state of charge.

Smart chargers, by detecting battery voltage and resistance from the battery prior to charging, are able to determine which stage to charge at.

Once it detects that the battery has reached 80% state of charge, the charger will enter the absorption stage.

At this stage, the charger will maintain a constant voltage, while the current declines. The lower current going into the battery safely brings up the charge on the battery without overheating it.

This stage takes more time. The charging current continuously falls off until the battery almost reaches full capacity.

At the end of this stage, the battery is approximately 98% charged.

 Keyword(s): Natural absorption ratebattery's absorption rate
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Acceleration is simply a change in speed.

Acceleration can be positive - an object speeds up, or it can be negative - an object slows down.

The kind of acceleration we all experience every day is the acceleration produced by gravity - 9.81m/s2, referred to as 'g' in engineering calculations.

For example, in order to calculate the weight of an object, we multiply its mass by the acceleration produced by gravity:

W=m.g

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During Phase 2, you will spend a lot of time working with lead-acid batteries. In order to protect your body and clothing from acid, you will be issued with an acid-proof apron.

You will also be issued with acid-proof gloves to protect your hands against acid.

You should wear the gloves, apron and your safety goggles whenever you work with lead-acid batteries.

 Keyword(s): acid proof apron
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During Phase 2, you will spend a lot of time working with lead-acid batteries. In order to protect your hands from acid, you will be issued with acid-proof gloves.

You will also be issued with an acid-proof apron to protect against acid spillages.

You should wear the gloves, apron and your safety goggles whenever you work with lead-acid batteries.

 Keyword(s): acid proof gloves
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This alerts the operator or the service technician that an electronic system malfunction is currently present. Refer to the term Diagnostic Code in this glossary.
 Keyword(s): Active diagnostic codes
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Imaginary lines drawn through the king pin and the track control rod end on each side of a vehicle will intersect at a point just in front of the rear axle of that vehicle. The angle they make with each other is known as the Ackermann angle.

The purpose of the angle is to allow the front wheels to turn through different angles when cornering. This is because the inside wheel always needs to turn through a bigger angle in order to get around the corner without scrubbing.

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Word formed by using the first letter of other words, for example:

RAM-Random Access Memory

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Unlike a passive sensor, an active sensor needs a power supply. There are 3 terminals on a pressure sensor. One is a supply, one is ground, and the third sends a signal back to the ECM.

Here, we can see the example of a pressure sensor. There are 3 terminals. We know this is an active sensor because it has these 3 terminals.

1. Pin A is a 5 volt supply into the sensor.
2. Pin B is common, meaning it is grounded to 0 volts.
3. Pin C sends a signal back to the ECM. From this signal, the ECM calculates the pressure acting on the sensor.
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In certain course modules, such as the small plant module, there are activity sheets for you to download. Once you do this, you should work your way through the sheet, carrying out all the activities listed, and researching answers to all the qeustions asked by searching this website, your own course notes and the world wide web.

The small plant module covers a large range of machinery, so it can be very difficult to cover everything.

Acitvity sheets will guide you to study all matters related to health and safety, theory and practical work. If you do all activity sheets, you will not come across anything in the practical or theory exams that you have not already researched as you worked your way through the activity sheets.

 Keyword(s): Activity sheets
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A needle-like probe used in automotive diagnostics when probing wires and connector blocks for electrical signals.

It is very easy to cause damage to wires, their insulation and to connector blocks when trying to diagnose electrical problems. You must make good metal to metal contact with electrical circuits to analyse them, but it is essential you do not cause any damage when doing so.

An acupuncture probe is smooth and pointed, allowing you to slide the probe into connector blocks without causing damage. The probe then connects to your voltmeter or oscilloscope by way of the standard 4mm connector.

 Keyword(s): acupuncture probes
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This denotes a self-learning system.
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This is a software process that is performed in the ECM that optimises engine performance.
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Sometimes, course participants may feel they can add more to an explanation given in this glossary. In cases like this, they can add comments. See the comment at the bottom of this entry. (Please note: comments are only visible to registered users who are logged in.)
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This is content over and above what is on the Phase 2 syllabus for CP Fitters.
It is sometimes posted on the site in order to help apprentices who may wish to find out a little more about certain topics or equipment that is covered during Phase 2.
Additional content will not appear in any Phase 2 examinations.

During the Electrical Module, there is a learning unit called 'Lighting Circuits'. During this unit, you will build various wiring circuits. One such circuit is an indicator (turn signal) circuit.
This type of circuit originally used what was known as a 'hot-wire' flasher unit. Nowadays, these older type flasher units have been replaced by electronic version.
If you would like to learn more about these more modern units, there is a page of additional information with an overview, links to data sheets and a video of the operation of a typical electronic flasher unit:
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This is the part of a browser window into which you can type the URL (the web address) of a website. If you know the exact URL of a site, you should type it in here.
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In the context of AC electrical circuits, admittance quantifies how well the circuit allow (admit) the flow of current.

The opposite to admittance (allowing the flow of current) would be impedance (opposing the flow of current).

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From the Aerial Platform Hire website:

Aerial Platform Hire is Ireland's leading work platform rental company. Founded in 1980 we offer for hire self propelled boom and scissor lifts manufactured mainly by JLG industries, the worlds largest manufacturer of powered access equipment. We also offer Telescopic Handlers from JLG and Manitou Buggiscopics. Hire is available from strategically located depots in Clane, Co. Kildare and Mallow, Co. Cork. We deliver machines throughout Ireland from both of these depots.