The Lucas generating system fitted to some Ford Falcon XK vehicles converts mechanical energy from the engine into electrical energy used to operate the ignition system, lighting system and other electrical accessories while maintaining battery charge.
The system consists of three principal components:
-
Generator (dynamo)
-
Voltage regulator
-
Battery
The generator produces electrical power while the engine is running. The voltage regulator controls the generator output to maintain correct system voltage, and the battery stores electrical energy for engine starting and electrical operation when generator output is low.
Lucas Generating System Operation
The generator used in this system is a negative-earth shunt wound two-pole, two-brush machine rated at 12 volts and approximately 25 amperes.
It operates together with a Lucas RB310 voltage regulator, which is connected between the generator armature and field circuits.
The generator is driven by a belt from the engine crankshaft pulley. The armature shaft is keyed to an integral pulley and cooling fan assembly.
As the engine rotates the generator, the fan draws cooling air through the generator housing and over the commutator and windings to prevent overheating.
The generator armature shaft is supported by permanently lubricated ball bearings located in the end plates.
Generator output varies depending on the state of battery charge and the electrical load placed on the system.
When the battery is low, the generator produces a higher charging output. As the battery approaches full charge, the regulator reduces generator output to maintain correct charging voltage.
Lucas Generator Routine Maintenance
Regular inspection helps ensure reliable generator operation.
Inspection of Brushgear
Approximately every 12,000 miles, the generator brushgear should be inspected by a qualified automotive electrician.
Worn or damaged brushes can cause poor charging performance and irregular electrical output.
Generator Drive Belt Inspection
The generator drive belt should be inspected periodically.
If slackness develops, adjust the belt tension by moving the generator on its mounting bracket.
Correct belt tension should be sufficient to drive the generator without slipping, but the belt should not be overtightened.
Overtightening the belt can place excessive load on the generator bearings.
Generator Alignment
When adjusting belt tension, ensure that the generator pulley is properly aligned with the crankshaft pulley.
Incorrect alignment can cause belt wear and unnecessary stress on generator components.
Lucas Generating System Trouble Diagnosis
Problems in the generating system usually appear as one of two general symptoms:
-
Battery not charging or low in charge
-
Charging rate excessively high
Either condition may result from faults within the generator, regulator, wiring or battery itself.
When diagnosing charging system problems, inspect the following components:
-
Generator drive belt condition and tension
-
Electrical wiring connections
-
Battery condition and charge level
-
Voltage regulator operation
-
Generator brushes and commutator
Accurate diagnosis should always be performed using properly calibrated electrical test instruments.
Correct regulator adjustment requires voltmeters capable of measuring to approximately 0.05 volt accuracy within the normal system range of 13 to 18 volts.
Ammeters used for generator testing should be accurate to within one ampere between approximately 20 and 30 amperes.
For reliable results, electrical test instruments should be calibrated annually, and the calibration date should be marked on the instrument.
Correct testing procedures will identify whether the fault lies in the generator itself, the regulator, or the external wiring circuit.
Safety, Copyright and Source Notice
Safety Disclaimer
Working on motor vehicles involves mechanical, electrical and chemical hazards. Always ensure the vehicle is safely supported, the engine is switched off when appropriate, and suitable safety equipment such as gloves and eye protection are used. If you are unsure about any repair or maintenance procedure, consult a qualified mechanic before attempting the work.
Source
Information compiled from period factory service literature.
Copyright © Car Manuals Direct. All rights reserved.
