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Supplier of 12v or 24v automotive alternators brand new outright with a full 12 month warranty*
or factory service exchange alternators rebuilt to manufacturers specification carrying manufacturer standard warranty*
Alternator repairs and component parts supplied
Completion of all form fields is not mandatory - information helps.
Please include any part numbers to assist alternator identification eg Bosch alternators usually have a 10 digit part no.
Local facilities to test many alternators for charging output on the vehicle or by free run bench test.
Services include strip, test, repair and rebuild of vehicle alternators to component level.
Cost effective specialist alternator repairs may include bench test or strip and test of individual alternator components then replacement such as fitting of a diode pack, bearings or voltage regulator to get your old alternator working again or fitting of a complete brand new or service exchange unit.
Repair of your existing alternator can offer a cheaper solution than replacing a complete unit but this depends on which component has failed. Minimum repair cost is normally above £50 taking account of labour. To purchase a complete alternator as aftermarket spare parts would be much more expensive than a mass produced factory built unit.
Supply of brand new oe and aftermarket alternator rebuild parts including diode rectifier pack - voltage regulator - bearings - rotor - stator - slip rings - casings - fasteners . Pleae note, alternator oe part numbers are required to source components. Most alternator parts can be sourced for next working day subject to time of order.
*Vehicle breakdown callout alternator supply & fitting service (on site where possible)
available to Shrewsbury, Telford & Local Shropshire areas.
Many 12v and 24 volt automotive alternator removals and replacements can be carried out on site.
Rotating electrics fitting service operated in Shropshire areas.
Battery test and vehicle charging system testing available.
Troubleshooting of alternator charging circuit problems
Auto electrical diagnostics wiring faultfinding and repair.
Test and repair facilities for many units
B+ , 30, Battery Positive
S, M, 2, Battery Voltage Sense
B- , 31, D-,GRD Battery Negative
F, DF , 67 , FLD , EXC, Field/Rotor
D+, 61 , L , IND, Charge Warning Lamp
IG, 15 , R , Ignition
N, C, Central Point
W, P, STA, Tachograph rev counter (stator single phase tap AC output)
DFM , FR, SIG, C, M, Digital Field Monitor duty cycle output for computer control unit monitoring.
LIN Local Interconnect Network bi-directional control to control module
COM bi-directional digital communication with control module
Please Check the manufacturers instructions for specific application of wiring terminal designation.
The automotive alternator is an electricity generation plant which provides power to recharge one or more vehicle batteries as well as supplying electricity for vehicle electrical systems such as lighting, wipers, heater motor, car audio ,sat nav, etc whilst the vehicle engine is running.
Alternators generate AC (Alternating current ) converted to DC (direct current) by the alternator rectifier (diode pack)
The term Rotating Electrics refers to Alternators, Dynamos, and Starter Motors
The Alternator is generally engine driven by drive belt connected to the crankshaft pulley , or coupling to shaft drive or gear drive. If drive belt driven correct belt tension is essential. The alternator must be mounted securely to enable it to be driven efficiently. Broken or loose mounting brackets can result in loss of drive belt tension and subsequent loss of alternator charging performance.
Alternator lifespan -Alternator lifespan of a motor car alternator is 100,000 to 200,000 miles, dependant upon operating conditions such as environment, temperature, driving cycle, maintenance, etc.
Engine oil and fluids leaking on to the unit.
Incorrect or poor electrical connection
Voltage Spikes eg from jump starting
A higher output alternator may be required when additional accessories are fitted or a secondary battery is fitted
The vehicle manufacturer calculates the power output of the alternator required for each vehicle with regard to original equipment fitment. Increasing the load on a vehicles electrical system may require an alternator system upgrade including cable. Special purpose vehicles with split charge dual battery systems may be fitted with an additional alternator or battery charging management system.
The vehicle alternator is normally engine driven via an auxilliary drive belt or sometimes direct drive and works by the principle of Magnetic induction ; When a conductor such as a wire moves through the lines of force of a magnetic field, a voltage is induced in the conductor. Whether the conductor moves in relation to the magnetic field or vice versa the principle is the same.
The Alternator Rotor consists of a central shaft, coil winding and magnetic claw poles.
The rotor assembly is supported on bearings. The alternator rotor and bearings rotate as it is driven from the engine.
Excitation current is passed to the rotor via copper slip rings which causes the electromagnet alternator rotor winding to magnetise when energised creating a magnetic field.
The alternator rotor may fail due to open or short circuit in the winding or break down of insulation. A bent or misaligned rotor shaft could cause vibration. Worn alternator bearings can also cause noise and vibration.
Alternator Excitation : Power is supplied to EXCITE the rotor to create a magnetic field. (excitation current is required to create a magnetic field unless permanent magnets are used ) Some alternators are SELF-EXCITED, this means after the rotor is initially excited a wire connected to the stator taps some of the power generated to keep the rotor excited and power generation in progress whilst the rotor is spinning. The brush pack or brushes form the means of connecting the spinning rotor copper slip rings to the excitation power source. Worn brushes and worn slip rings can prevent excitation current passing to the rotor causing the alternator to fail to charge.
The stator normally consists of three windings of reasonably heavy gauge copper wire connected in Star or delta formation around a soft iron laminated core sandwiched between the alternator housing. Stator windings may be connected to the rectifier pack by soldering or on higher output applications by laser or resistance welding.
The electrical power output of the alternator is generated in the stator as a 3 phase alternating current (a.c.)
The alternator voltage regulator functions to limit alternator output voltage to prevent overcharging of vehicle batteries which would cause electrolyte to boil off and cell failure (the rotten egg smell). Excessive voltage also causes havoc with electronic control units ,motor speed regulation, and bulbs to blow.
Control of the alternator rotor excitation current proportionally controls magnetic field strength.
Excitation field power control is used to regulate alternator output by means of the Voltage regulator.
With ECU regulated systems, the duty cycle of the excitation current can be reflected as a feedback signal to measure the amount of alternator capacity being used via the DFM signal terminal (DF Monitor).
A diode acts like a non return valve in an electrical circuit allowing current to flow one way.
The initial 3 phase alternating current (a.c.) output produced from the alternator
stator cannot be used to recharge vehicle batteries so has to be converted to direct current (d.c.).
The process of converting AC power to DC power is known as rectification.
The rectification is done by the Diode pack (a diode acts like a one way valve in an electrical circuit).
Car alternators are Three Phase AC generators with rectification to DC.
The DC voltage level produced by the alternator must be slightly higher than battery voltage to allow the battery to charge.
The Diode pack has a secondary function when the ignition key is off to prevent power draining from the vehicle battery via the alternator windings which would cause the battery to discharge.
The diode bridge is connected to stator wires. Jump starting, reverse polarity, and voltage spikes can cause alternator diode failure leading to the alternator not charging. Diode failure can be diagnosed by oscilloscope signal testing of the alternator with the engine running , or by multimeter diode test function. Diode packs can be supplied seperately.
Battery light staying on ? Have the vehicle battery and vehicle electrical charging system tested.
A visual check with the engine stopped should be carried out to ensure the alternator is secure and drive belt correctly
tensioned. Also check for oil ,fuel or coolant leaks which may have caused the alternator to fail.
Check all connections are tight and wires are in good condition. Check all heat shields are in place .
A quick test to diagnose a failed alternator is to measure battery voltage with the engine off using a multimeter set to dc volts range. Start the engine and run at around 2000rpm whilst monitoring battery voltage reading which should have increased slightly if the alternator is charging the battery.
Incorrect alternator output voltage ( alternator overcharging or undercharging ) can affect sensitive vehicle computer systems and related systems.
Typical battery voltage for a 12 volt system would be :
Excess drive belt tension
Insufficient drive belt tension may cause a squealing noise.
Stator winding fault causing phase imbalance
Noisy one way clutch pulley may indicate that the drive pulley needs renewal. These are available seperately but may require special tools to fit.
Water leaks on to the alternator : Water entering an air cooled alternator can cause problems particularly in Winter when at freezing temperatures the water turns to ice causing internal component damage .
On modern alternators controlled by an electronic control unit an incorrect battery type may cause problems.
Alternator translated : Alternateur Alternador Alternatore Dynamo Generatoren Lichtmaschine 发电机 алтернатор