FAW Generator: An Expert Guide to Its 3 Key Components

Welcome to this expert technical guide on the FAW Generator assembly (Part No. 3701010-36D), the core of the electrical power system for the FAW Jiefang CA4251P66K24T1A3E5 6×4 diesel semi-trailer tractor. This component is essential for all vehicle operations.

The FAW Generator, technically an AC (Alternating Current) Generator or “alternator,” is a high-output component responsible for two critical tasks: it recharges the truck’s batteries and provides all the electrical power needed to run the engine’s ECU, fuel injectors, lighting, HVAC, and all other onboard electronics.

This guide is an essential resource for professional technicians and fleet managers. Although the parts list is simple, it represents a complex system. We will deconstruct the entire FAW Generator assembly, its internal logic, and its critical mounting hardware, down to the smallest serviceable unit.

Core Component: The AC Generator Assembly (3701010-36D)

The main component is the ‘AC Generator Assembly’ (3701010-36D), which is the complete FAW Generator unit. This is a heavy-duty, high-amperage alternator (likely 100 amps or more at 24 volts) specifically designed for the demands of a commercial tractor. Its function is to convert mechanical energy from the engine’s serpentine belt into usable DC electrical energy.

The FAW Generator is not a simple motor. It operates by spinning an electromagnet (the **Rotor**) inside a fixed set of wire coils (the **Stator**). As the engine spins the generator’s pulley, the magnetic field of the rotor “cuts” across the stator windings, inducing an Alternating Current (AC) in the stator. This AC is the raw power generated by the unit.

This AC is not usable by the truck’s 24-volt DC system. Therefore, the “logic” of the FAW Generator lies in its two internal electronic components: the rectifier and the voltage regulator. These components are typically housed inside the rear cover of the FAW Generator assembly.

Internal Logic: The Rectifier and Voltage Regulator

A key part of the FAW Generator assembly is the **Rectifier Bridge**. This is a solid-state electronic component, typically a set of six or more high-power diodes. These diodes act as one-way electrical valves. They capture the AC sine wave from the stator windings (which swings from positive to negative) and “flip” the negative half, converting the entire output into a pulsating Direct Current (DC). This DC is what is sent to the battery and the rest of the truck.

The **Voltage Regulator** is the “brain” of the FAW Generator. The truck’s electrical system is extremely sensitive and demands a constant voltage (e.g., ~28.4 volts for a 24V system) to safely charge the batteries and power the ECU. However, the FAW Generator‘s output is directly tied to engine speed; it produces less voltage at idle and far too much at high RPM.

The regulator solves this. It constantly monitors the battery voltage. If the voltage drops below the target (e.g., 28.4V), the regulator sends *more* electrical current to the spinning rotor via a set of “slip rings” and “brushes.” This makes the rotor’s electromagnet *stronger*. A stronger magnetic field induces more power in the stator, and the voltage rises.

Conversely, if the voltage climbs *above* the target, the regulator sends *less* current to the rotor. The electromagnet weakens, less power is induced, and the voltage drops. This constant feedback loop, happening hundreds of times per second, is what provides the stable, “regulated” voltage. A failure in the regulator is a common reason for replacing a FAW Generator, as it can lead to dead batteries (under-charging) or a fried ECU (over-charging).

The Mounting System: Bolts (3701327-36D) and Nuts (CQ32610)

The parts list for the FAW Generator assembly details its mounting hardware. This is a critical system, as the generator is a heavy component that is under a constant, high-tension side-load from the serpentine belt.

The ‘Bolt – for fastening AC generator’ (3701327-36D), of which there are two, are the main fasteners. On a heavy-duty FAW Generator, this is often a “stud” system. These studs are threaded into the engine’s main mounting bracket. The generator is then slid onto these studs.

The ‘Hex head flange lock nut’ (CQ32610) is the key to securing the FAW Generator. The list calls for two nuts, matching the two studs. These are not simple nuts; they are **flange lock nuts**.

**Flange:** The base of the nut is “flanged,” meaning it has a wide, integrated washer. This washer distributes the clamping force over a wider area of the FAW Generator‘s aluminum mounting ears, preventing it from cracking.

**Lock:** The nut is a “lock nut,” meaning it is “prevailing-torque.” It is either “top-lock” (distorted at the top) or “nylon-insert” (though less common in high-heat areas). This design means the nut actively resists backing off from the intense vibration of the diesel engine. A standard nut would vibrate loose, causing the FAW Generator to lose belt tension and stop charging.

This robust stud-and-lock-nut system is what allows the FAW Generator to be securely mounted, but also allows it to pivot on one of the bolts, which is necessary for setting the proper serpentine belt tension.

FAW Generator Parts List

The following table provides the complete, detailed breakdown of all 3 components identified in the ‘Generator’ diagram for the FAW CA4251P66K24T1A3E5 tractor. This FAW Generator system is the foundation of the vehicle’s electrical health.

Technical Specifications and Assembly Context

The specifications for the FAW Generator are defined by its function as a high-output, heavy-duty electrical power source. The entire FAW Generator system is designed for maximum reliability and service life.