Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
LUCAS Alternators: Description
Lucas ACR model alternators have an integral voltage regulator mounted in the slip ring end bracket. The stator consists of star-connected, 3 phase windings on a ring end cover and drive end bracket. The rotor is either an 8 or 12 pole type with the field windings connected to 2 face-type slip rings. It is supported in the drive-end bracket by ball bearings and in the end cover by needle roller bearings. One positive and one negative carbon brush ride against concentric brass slip rings. The heatsink-rectifier, terminal block assembly incorporates 6 silicon diodes, forming a full wave rectifier bridge circuit, and 3 diodes which supply current to the rotor windings.
| Model | Type. No. | ||
|---|---|---|---|
| Jaguar XJ6 | 25 ACR | ||
| Triumph | |||
| TR7 | |||
| Standard | 17 ACR | ||
| Heavy Duty | 20 ACR | ||
| With A/C | 25 ACR | ||
| TR8 | |||
| Standard | 17 ACR | ||
| With A/C | 25 ACR | ||
| Nominal Output | ||
|---|---|---|
| Alternator | Amps@6000 RPM | Voltage |
| 17 ACR | 36 | 14 |
| 20 ACR | 66 | 14 |
| 25 ACR | 65 | 14 |
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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