Distributors & Ignition Systems - LUCAS Constant Energy Ignition: Description
The Lucas Constant Energy Ignition System maintains energy stored in the ignition coil at a constant level, allowing the output voltage to remain constant over a wide range of engine speeds.
The system also provides for a variable dwell for more optimum performance. A long dwell is provided at high speeds for adequate energy storage in the coil. A dwell is provided at lower speeds for minimum power loss.
The power lost in both the coil and amplifier module is greatly reduced, compared to equivalent constant dwell systems. The system includes a breakerless distributor, amplifier module, an ignition coil, ignition switch, and battery. See Fig 1. No ballast resistor is required.
The distributor has conventional centrifugal and vacuum advance systems, an anti-flash shield, rotor, reluctor, and pick-up coil. See Fig 2. The reluctor is a gear-shaped component with 6 or 12 teeth, one for each cylinder of the engine. It is mounted on the distributor shaft.
The pick-up coil includes a winding, pole piece and a permanent magnet. A 2-wire shielded harness connects it directly to the amplifier module. The amplifier module, housed in an aluminum case, is located near the distributor. It has a 2-wire harness, which connects to the coil primary terminals.
On XJS models, 2 ignition coils are used. See Fig 2. The main coil is connected in parallel with the primary windings of the auxiliary coil. The secondary circuit of the auxiliary coil is not used and the coil tower is sealed. Amplifier modules are not interchangeable between models.