Diesel Generator Sets: Essential Knowledge, Classification, and Pricing Explained

Diesel generator sets are essential backup power solutions widely used across industries including hospitals, construction sites, data centers, factories, and more. As a compact power source driven by an internal combustion engine, a diesel generator ensures uninterrupted power supply during outages or in areas without grid access.

However, during the procurement process, many buyers often wonder: Why do prices vary so significantly even for the same brand or power rating? In this article, we will explore the types, structure, applications, performance grades, installation standards, and most importantly, the factors that affect the price of a diesel generator set.

What is a Diesel Generator Set?

A diesel generator set (genset) uses a diesel engine to drive an alternator, converting diesel fuel into electrical energy. Its compact size, mobility, ease of operation, and low maintenance make it suitable for both primary and standby applications.

Types of Diesel Generator Sets

Diesel generators are classified in multiple ways, including:

1. By fuel type: Diesel-only or dual-fuel gensets

2. By speed: High-speed, medium-speed, and low-speed engines

3. By application: Land-use (mobile/fixed), marine, trailer-mounted, and vehicle-mounted

4. By output voltage & frequency:

   • AC generators (typically 50Hz or 60Hz)

   • DC generators

5. By excitation method: Rotating AC exciter or static excitation

6. By usage: Prime, standby, or emergency power

7. By control operation: Manual, remote, or fully automated

8. By automation: Basic models, automatic start models, microcomputer-controlled units

Applications of Diesel Generators

Diesel generators are used in:

• Mining operations

• Railways and remote job sites

• Road and traffic infrastructure

• Factories and enterprises

• Hospitals and data centers

Despite lower power output compared to utility-scale power, diesel generators offer flexible deployment, fast response time, and reliable backup or primary power in critical applications.

Main Components of a Diesel Generator

A complete diesel genset typically includes:

• Diesel Engine

• Alternator (Generator)

• Base frame with built-in fuel tank

• Control panel / ATS (Automatic Transfer Switch)

• Cooling system (air-cooled or water-cooled)

• Muffler / Silencer

• Soundproof enclosure (for silent types)

How Does a Diesel Generator Work?

Diesel generators convert chemical energy into electrical energy using the following process:

1. Clean air enters the cylinder via the air filter.

2. Diesel fuel is injected under high pressure and mixes with compressed hot air.

3. The mixture ignites, causing an explosion that drives the piston downward.

4. The piston’s motion turns the crankshaft.

5. The crankshaft is connected to a synchronous alternator rotor.

6. Electromagnetic induction generates AC electrical power.

The entire process is controlled by an intelligent controller that manages safety features, voltage regulation, and fault monitoring.

Performance Ratings (Per GB/T2820.1-1997 Standard)

Diesel gensets are categorized into four performance grades:

• G1: Basic applications such as lighting or simple electrical loads

• G2: Suitable for pumps and fans with moderate voltage/frequency deviations

• G3: Precision equipment like telecoms and controlled loads

• G4: High-performance applications such as data centers and computer systems

Understanding Model Codes

In China, diesel generator models follow a standard code format indicating:

• Rated power (kW)

• Output current type (e.g., G for AC, Z for DC)

• Type (e.g., F for land-use, FC for marine)

• Automation level (e.g., Z for automatic, S for silent)

• Design sequence and variation codes

• Environmental adaptation (e.g., TH for humid/tropical conditions)

Note: International or joint-venture models may have custom model codes.

Diesel Generator Installation Guidelines

1. Ventilation

• Air Inlet: Sized according to genset power

• Air Outlet: Must match heat dissipation requirements

2. Exhaust System

• Must be properly routed outdoors with a muffler

• Exhaust pipe angled 60° or covered with rain/snow caps

3. Foundation

• A reinforced concrete base is essential

• Use expansion bolts to secure the genset via the steel skid base

What Affects Diesel Generator Pricing?

A. Cost Breakdown

• Engine: ~80% of total cost

• Alternator + Controller + Accessories: ~20%

Gensets can be supplied in three configurations:

1. Fully Internation well-know brand: All parts from the same international brand

2. Domestic assembly with mixed brands: Engine, alternator, and controller sourced separately

3. Complete Chinese Brand: Using reputable Chinese brands like Yuchai, SDEC, Weichai, etc.

B. Additional Costs

• Installation, transport, commissioning

• Exhaust treatment system & compliance certification

• Noise control engineering (enclosure + room treatment)

• Exhaust ducting beyond the generator room

Example Cost Breakdown – 1000kVA Cummins Generator (Joint Venture):

• Generator Set: $80,000

  • Engine: $60,000

  • Alternator: $10,000Frame(Container Enclosure): $10,000

• Installation: $3,000

• Exhaust Treatment: $1,000

• Generator Room Noise Treatment: Quote based on drawings

• External Exhaust Ducting: Quoted per request

Price Differences by Major Components

1. Engines

• High-end brands like Mercedes-Benz cost ~20% more than mainstream choice

• Other JV brands like Perkins, Mitsubishi, Cummins: Cummins is the choice of most people, high economical choice

• Top Chinese brands: 15%–30% cheaper than JV/foreign brands: Weichai, SDEC etc.

2. Alternators

• Domestic brands like Stamford (Wuxi), Marathon (Shanghai), Faraday, and Leroy-Somer (Fuzhou) all priced around $10,000 for 1000kVA

• Minimal pricing differences

3. Control Panels

• Brands like SmartGen, Deep Sea, and ComAp 

• Price differences are negligible due to mature technology

Final Thoughts

When selecting a diesel generator set, consider not only the brand and rated power but also:

• Engine configuration

• Application environment

• Fuel efficiency and reliability

• Control system features

• After-sales service and certification

Understanding the technical configuration and cost structure can help avoid overpriced offers and ensure you get the best value.

Related Resources:

• How to Choose a Reliable Diesel Generator Manufacturer

• Top Diesel Generator Brands in China

For more details or quotations, contact us at:

Email: jack@hosempower.com

Whatsapp: +86-13205904365