Auto Electrics Mobile Product Services Shropshire
Tel 01743 884888
Alternator voltage regulator supply
Repair and Rebuild components for Vehicle Alternators
Alternator Parts Supply UK Mail Order
Supplier of automotive alternator components
Please use the enquiry form below for replacement alternator mail order prices:
(Completion of all form fields is not mandatory but all information helps. Please include any part numbers to assist alternator identification)
Common Alternator Wiring Terminal Letter Designations
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.
Alternator Voltage Regulator function
A Voltage regulator controls the excitation current of the alternator rotor therefore the magnetic field strength is proportionally controlled. This excitation control is used to regulate the alternator output by means of the Voltage regulator.
DFM: Digital Field Monitor terminal
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).
Power is supplied to EXCITE the rotor so the magnetic field is created. (Without excitation current there will not be a magnetic field) 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.
Brushes : Brush pack
The brush pack or brushes form the means of connecting the spinning rotor to the excitation power source.
Symptoms of a faulty alternator voltage regulator
Possible signs include illumination of vehicle battery charge warning light on dashboard whilst the engine is running followed by gradual loss of electrical power until the engine cuts out and fails. The discharged battery can prevent the vehicle engine from being started.
Check all connections are tight and wires are in good condition.
A quick check for a failed alternator is to measure battery voltage with the engine off using a voltmeter. Start the engine and run at around 2000rpm whilst monitoring battery voltage which should have increased slightly if the alternator is charging the battery. B+ terminal voltage at the alternator should also be checked.
Incorrect alternator output voltage ( alternator overcharging or undercharging ) can affect sensitive vehicle computer systems and related systems.
Typical battery voltage readings for a 12 volt system :
Some modern vehicles have alternators with dynamic electronically controlled output which is affected by the embedded software in the vehicle engine control computer. These require specialist equipment to test and verify as output varies with demand.
|Voltage Regulator part number||Fits Unit||Typical Application|
|F00M145225||0124315001, 0124315005||VW ,Audi, Skoda ,SEAT|
Unit warranty is subject to original suppliers standard terms & conditions.
Alternator Repair , Recondition , Supply, Fitting.
Shrewsbury 01743 884888Alternator Identification
Alternator units are identified by alternator manufacturers part number eg Bosch 10 digit part no 0 120 ....., Hitachi LR....., Valeo A...V... , Lucas LRA...., Mitsubishi A..T..., Nikko ..., Nippondenso part no...,
Vehicle manufacturers part no may also be labelled.
Alternator voltage and current output rating may also be stated.