184000363 - INTRODUCTION - CURRENT GENERATOR

ALTERNATOR

COMPOSITION

The alternator is a rotary machine which transforms mechanical energy into electrical energy.

1 - Rotor electro-magnetic circuit2 - Fitting rods3 - Rectifier side support4 - Negative heat dissipation plate5 - Positive heat dissipation plate6 - Zener type press fit power diode7 - Manifold8 - Regulation unit9 - Heat shield cap10 - Rectifier side bearing11 - Rectifier side inner fan12 - Stator electronic circuit13 - Control side support14 - Control side inner fan15 - Control side bearingLike all electric machines, it basically consists of two parts: a rotor and a stator.The diagram below shows the rotor for an alternator with internal ventilation.

Rotor

The rotor is composed of a cylindrical magnetic core, concentric to the drive shaft, which has a toroid coil and two opposing magnetic impellers which are magnetized by the winding in the actual core.The impellers have six, claw-shaped, poles each, which interpolate reciprocally so that there are alternately six North poles and six South poles. There is therefore a single rotor winding which produces the e.m.f. for all the partial magnetic circuits.

Stator

The diagram below illustrates the stator.

1 - Star conection stator2 - Triangular connection statorThe stator consists of a ring-shaped laminated group joined by two or more axial welding seams on the outside. It usually has thirty six grooves which contain the three-phase winding made from insulated copper wire with vinyl acetate and is connected, as necessary, by a star or triangular connection.

Rectifier bridge

The diagram shows the rectifier bridge.

1 - Zener type power diode2 - Dissipation plate3 - Terminal B + alternatorBridge specifications

The bridge consists of:

Zener press fit diodes
Diodes fitted on the dissipation plates electrically connected to the connection terminals with the phases.
Dissipation plates.
Large size dissipators.
Phase insulation until the connection with the bridge through a rubber cable loom.
Excess voltage limitation if the ''+ battery'' loads are disconnected guaranteed by the zener diodes.

1 - Normal diode2 - Zener diodeZener diodesIf the diodes are polarized directly they both allow the current to pass from the anode to the cathode (V+ I+): a zener diode therefore behaves like a normal silicon diode.If polarized inversely, initially the current does not flow from the cathode to the anode up to VZBeyond VZ a normal diode is ruined, but a zener diode, on the other hand, continues to work normally because its resistance in these conditions decreases sharply. A zener diode is therefore a voltage stabilizer diode. On cars the voltage ranges from 4.7 to 24 Volt. It is one of the most important components in the regulation unit.It is often used for protection against polarity inversion or excess voltage.

ALTERNATOR WITH INTERNAL VENTILATION SPECIFICATIONS

The main feature of this type of alternator, with a 115 mm diameter stator, is having dual internal ventilation with the vanes inclined to guarantee the maximum flow of air and, at the same time, limit noise.Alternators with internal ventilation, for the same power supply, are smaller and lighter than types with external ventilation and satisfy all current application requirements (space in engine compartments is always at a premium). In addition to this, in terms of quality, these alternators are more reliable and durable than the best the competition currently has to offer on the market.In depth studies and research have made it possible to introduce all the devices, in production, designed to limit the noise produced by various components (fluid dynamics, mangetic, mechanical).

Typical voltage curve

The graph below shows a typical regulator voltage cuve.

Technical data

The table summarizes the types of alternator used on this vehicle.

-	1.4 16v WITH HEATER	1.4 16v WITH AIR CONDITIONING	1.3 JTD WITH HEATER	1.3 JTD WITH AIR CONDITIONING
ALTERNATOR''	A115IM 14V - 45/70A	A115IM 14V - 50/90A	TG8 14V - 75A	TG9 - 14V - 90A

Wiring diagram

The diagram shows the operation of the alternator

1- Alternator2 - Interference condenser3 - Regulation unit4 - Energizing rotor5 - Electric field stator6 - Zener diode rectifier bridge7 - Alternator recharging light in the instrument panel8 - Body Computer9 - CAN linesOperationWith the alternator not working and the ignition key in the ON position, the Body Computer lights up the warning light in the instrument panel and sends a power supply to the voltage regulator incorporated in the actual alternator via terminal D+.In these conditions the energizing circuit (rotor) is enabled to earth by the regulator electronics.With the alternator rotating through the effect of the alteration in the number of revs and the mangetic field, a three-phase alternating volage is produced in the electrical circuit (stator) which, rectified by the diode bridge, can come out of terminal B+.When the upper fixed calibration level is reached (13.7 - 14.2 V) the battery is charged and it supplies the system.The Body Computer checks the efficiency of the alternator recharging system by measuring two parameters: the voltage signal coming from alternator terminal D+ and the engine rpm signal received at the CAN network from the engine management control unit.At the key on, as long as the voltage is below around 5.5V, the Body Computer signals that the charging is insufficient; when the voltage goes above 5.5V, the warning light goes out; if, on the other hand, with the engine moving (speed above 700 rpm), the voltage drops below the level of 4.5 V, the warning light comes on constantly. accompanied by a fault message in the display.

BATTERY

SPECIFCATIONS

The main features of batteries used on new models are the mounting plates made from active materials produced through the calcium lead production technology which has replaced the older antimony- lead type.This involves a mechanical stretching process for a continuous lead band to reach the final productio of a grille covered in lead oxides for the positive poles and metallic lead only for the negative poles, instead of the use of casting machines to produce grilles for fusion.The use of a material such as lead-calcium-tin alloy guarantees a considerable reduction in the electrolysis during the operation of the accumulator (dissociation of the water into its components of hydrogen and oxygen) where the gases can escape resulting in reduced evaporation of the actual water with a drastic reduction in the maintenance required for this type of battery.

1 - Cover2 - Cap edge3 - Positive plate4 - Negative plate5 - Separator6 - Bridges7 - Electrolyte8 - Water gauge9 - Negative pole10 - Monobloc11 - Maximum electrolyte level12- Minimum electrolyte level13 - Cap

Battery electrical specifications

Lead accumulator, low maintenance type.Cover: EURODIN with ramp type sealing elements on cover; press-fit caps (one cap per element) with protection system against fluid penetration from the outside. Gas evacuation through caps with gas/liquid separation systemCover seal: heat welding.Attachment to the base: joined on four sides.Poles: lead bushes produced through cold-pressing with sealing labyrinth in the press-work area on the cover.Electrolyte level check: through the openings in the caps in the cover, checking the consistency between the indicator (dipstick) and the electrolyte level. The dipstick indicates the max. level allowed, therefore the electrolyte should just come into contact with the lower end of the dipstick. The min. level is reached when the electrolyte exceeds the top end of the separators and/or plates by 10 mm.Water gauge for checking min. electrolyte level and battery charge.No. of plates: 6 positive + 5 negative.Grille alloy: lead-calcium-tin.Separator thickness: 1.15 mm.Plate thickness: positive 1.80 mm; negative 1.60Electrolyte density: 1280 ± 10 g/dm3 at 25°C with battery 100% charged.

Electrolyte density at 25° Celsius:

1280 g/litre 100 % of charge
1240 g/litre 75 % of charge
1200 g/litre 50 % of charge
1160 g/litre 25 % of charge
1120 g/litre drained
1110 g/litre totally drained.

CONTROL SYSTEM

This battery has an indicator for checking the battery which is a water gauge which makes it possible to qualitatively monitor the level of the electrolyte and the battery charge; this also allows the Customer to initially check the efficiency of the battery. this also allows the Customer to initially check the efficiency of the battery.This device consists of a transparent plexiglas cylinder: one end contains an indicator fixed to the battery cover; on the other end there is a drip tray, made from an acid-resistant material, drilled in such a way to allow the battery electrolyte to come into contact with a green coloured ball which is housed in the drip tray and can slide along a plane inclined towards the centre of the area of the cylinder.To sum up, the colour of the indicator reflects the state of the battery charge as set out in the table below.

	CONDITION 3	CONDITION 2	CONDITION 1
Information visible	Light, bright colour	Dark colour with green area in the centre	Dark colour with green area in the centre
Electrolyte level	Below minimum	Correct	Correct
State of charge	Indeterminate	Battery discharged	from 55% to 100%
Action to undertake	Top up electrolyte with distilled water	Recharge the battery	No action

This device:

does not give readings concerning a possible internal short circuit;
the density of the electrolyte varies with the temperature;
a prolonged stop could halt the mixing process of the reagents and thereby lead to a measurement which could refer to the surface layers only.
if the electrolyte level is low then there are no reliable readings.

To sump up the approximation of the measurement is around 15% (battery charge indicator calibration = 70% ± 15%).As a result of this reading error, it is necessary to check the battery charge more accurately in a Service Situation.

Cap

In low maintenance type batteries with lead-calcium-tin elements the seal is guaranteed by the press-fit caps with an anti-penetration system with a gas evacuation device through the actual caps.

The caps which allow the escape of the gases produced in the battery prevent the leakage of liquid. The cap consists of:

The cap casing: it acts as to prevent liquids escaping, but allows gas to escape through special openings.
The labyrinth: it prevents the particles which are released during the operation of the battery from obstructing the special diaphragm.
The semi-pervious diaphragm: thanks to a special layer of PTFE (poly-tetra-fluoro-ethylene) it prevents the escape of liquid, allowing the gases which are produced during the normal operation of the battery to pass through.

1 - Cap casing2 - Labyrinth3 - Diaphragm

BATTERY TECHNICAL SPECIFICATIONS

The table summarizes the main battery technical data.

BATTERY	1.4 16v WITH HEATER	1.4 16v WITH AIR CONDITIONING	1.4 16v ''COLD COUNTRIES''	1.3 JTD
CAPACITY	40 Ah	50 Ah	60 Ah	50 Ah
INTENSITY	200 A	250 A	380 A	350 A

BATTERY DISCHARGE IN REST CONDITIONS

Correct battery dimensions for model / trim level have been calculated to take into account power uptake when the ignition is switched off.This absorption should not exceed 0.6 mA for each Ah of battery capacity; this is to ensure that, if the vehicle has been left for one month with all the consumers not controlled by the ignition switched on, residual battery capacity is half of nominal capacity, i.e. enough charge is left to start up the engine under normal environmental temperature conditions.The table below gives several examples.

Battery	Max. absorption
40 Ah	24 mA
50 Ah	30 mA
60 Ah	36 mA

Checking/topping up battery fluid level

Undo the caps on the battery co

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