3939028
Alternator
Cummins®

The Cummins 3939028 Alternator is a component designed for use in commercial trucks. It serves a significant role in the electrical system of these vehicles, ensuring that the battery remains charged and that electrical components receive the necessary power while the engine is running. Understanding its function and importance can help in maintaining the overall efficiency and reliability of the truck.

Basic Concepts of Alternators

An alternator is a device that converts mechanical energy into electrical energy. It plays a role in the electrical system of a truck by generating electricity to power the vehicle’s electrical components and charge the battery. Unlike generators, which produce direct current (DC), alternators produce alternating current (AC), which is then converted to DC by a rectifier within the alternator. This conversion is crucial for the efficient operation of modern vehicle electrical systems ¹.

Purpose of the 3939028 Alternator

The Cummins 3939028 Alternator is designed to maintain the electrical system’s integrity in commercial trucks. It functions by converting the engine’s rotational energy into electrical energy, which is used to charge the battery and power electrical components such as lights, radios, and other systems. This ensures that the truck operates smoothly and that all electrical systems function as intended.

Key Features

The Cummins 3939028 Alternator incorporates several key features that enhance its performance and reliability. Its design includes high-quality materials that contribute to its durability. Additionally, it may feature technological advancements such as improved efficiency in power conversion and enhanced cooling systems to maintain optimal operating temperatures.

Benefits

Using the Cummins 3939028 Alternator offers several advantages. Its reliability ensures consistent performance under various operating conditions. The efficiency of the alternator means it effectively converts mechanical energy into electrical energy with minimal loss. Furthermore, its durability contributes to reduced maintenance needs and longer service life, which are beneficial for the overall performance and maintenance of the truck.

Installation

Proper installation of the Cummins 3939028 Alternator is important for its effective operation. It is recommended to follow Cummins’ guidelines and any specific requirements to ensure the alternator is correctly mounted and connected. This includes verifying that all electrical connections are secure and that the alternator is properly aligned with the engine’s pulley system.

Troubleshooting

Common issues with the Cummins 3939028 Alternator may include electrical faults, bearing wear, or rectifier failure. Diagnosing these problems involves checking for proper voltage output, inspecting the alternator for physical damage, and ensuring all connections are secure. Identifying signs of alternator failure, such as dimming lights or a dead battery, can help in addressing issues promptly.

Maintenance

To ensure the longevity and optimal performance of the Cummins 3939028 Alternator, regular maintenance is recommended. This includes periodic checks for loose connections, cleaning the alternator to remove any debris, and monitoring its performance. Knowing when to consider replacement based on the alternator’s condition and performance can prevent unexpected failures.

Cummins Corporation

Cummins Inc. is a global power leader that designs, manufactures, and distributes a wide range of power solutions. With a history of innovation and quality, Cummins has established a strong reputation in the commercial truck industry. The company’s commitment to advancing technology and meeting customer needs is evident in its product offerings, including the Cummins 3939028 Alternator ².

Cummins Alternator 3939028 Compatibility

The Cummins Alternator part number 3939028 is designed to fit a variety of Cummins engines, ensuring reliable power generation and efficient charging of the vehicle’s battery. This alternator is engineered to meet the specific needs of several engine models, providing robust performance across different applications.

Compatible Engines

QSB Series:

• QSB3.9 30 CM550
• QSB4.5 CM850 (CM2850)
• QSB5.9 30 CM550
• QSB5.9 44 CM550
• QSB6.7 CM2250
• QSB6.7 CM850 (CM2850)

The QSB series engines are known for their versatility and durability, making them suitable for a range of applications from agricultural to industrial use. The 3939028 alternator is engineered to handle the specific power demands and operational conditions of these engines.

QSC and QSL Series:

• QSC8.3 CM850 (CM2850)
• QSL9 CM850 (CM2850)

The QSC and QSL series engines are typically used in heavy-duty applications, including construction and mining equipment. The 3939028 alternator is designed to provide the necessary power output to support these demanding environments.

Other Cummins Engines:

• 4B3.9
• 6B5.9
• 6C8.3
• B3.9 G
• B4.5
• B5.9 GAS PLUS CM556
• C GAS PLUS CM556
• G8.3

These engines span a range of applications, from smaller machinery to larger industrial equipment. The 3939028 alternator is compatible with these engines, ensuring they receive the power they need to operate efficiently.

Grouping by Engine Series

QSB Series:

• QSB3.9 30 CM550
• QSB4.5 CM850 (CM2850)
• QSB5.9 30 CM550
• QSB5.9 44 CM550
• QSB6.7 CM2250
• QSB6.7 CM850 (CM2850)

QSC and QSL Series:

• QSC8.3 CM850 (CM2850)
• QSL9 CM850 (CM2850)

Other Cummins Engines:

• 4B3.9
• 6B5.9
• 6C8.3
• B3.9 G
• B4.5
• B5.9 GAS PLUS CM556
• C GAS PLUS CM556
• G8.3

This detailed compatibility information ensures that users can confidently select the 3939028 alternator for their specific engine needs, knowing it is designed to work seamlessly with a wide range of Cummins engines.

Understanding the Role of Part 3939028 Alternator in Engine Systems

The alternator, specifically part 3939028, is a vital component in the electrical system of an engine. Its primary function is to convert mechanical energy from the engine into electrical energy, which is then used to power the vehicle’s electrical systems and recharge the battery.

Integration with Engine Components

1. Crankshaft and Belt Drive System: The alternator is typically driven by a belt connected to the engine’s crankshaft. As the crankshaft rotates, it spins the alternator, enabling it to generate electricity.

2. Battery: The alternator works in conjunction with the battery to maintain the vehicle’s electrical system. It recharges the battery while the engine is running, ensuring a consistent power supply.

3. Voltage Regulator: This component monitors and regulates the output of the alternator to prevent overcharging of the battery. It ensures that the electrical system operates within safe voltage levels.

4. Electrical Wiring: The alternator is connected to the vehicle’s electrical system via wiring harnesses. These wires distribute the generated electricity to various components, such as lights, ignition systems, and electronic control units.

5. Starter Motor: Although the starter motor’s primary role is to start the engine, the alternator supports its function by ensuring the battery has sufficient charge for repeated starts.

6. Instrument Cluster: The alternator provides power to the instrument cluster, allowing gauges and warning lights to function correctly.

7. Entertainment Systems: Modern vehicles often include entertainment systems that rely on a stable electrical supply from the alternator.

8. Lighting Systems: Headlights, taillights, and interior lights all draw power from the alternator, ensuring they operate efficiently.

9. Power Steering and Braking Systems: In some vehicles, the alternator also supports the power steering and braking systems by providing necessary electrical power.

By understanding how part 3939028 alternator interacts with these components, engineers and mechanics can better diagnose issues, perform maintenance, and ensure the overall efficiency of the vehicle’s electrical system ³.

Conclusion

The Cummins 3939028 Alternator is a critical component in the electrical system of commercial trucks, ensuring the battery remains charged and electrical components receive the necessary power. Its design, featuring high-quality materials and technological advancements, contributes to its reliability, efficiency, and durability. Proper installation, regular maintenance, and understanding its integration with engine components are essential for optimal performance and longevity.