What factors need to be considered when purchasing a diesel generator set? Friends who have procurement plans in the near future can take a look to avoid pitfalls.

What factors need to be considered when purchasing a diesel generator set? Friends who have procurement plans in the near future can take a look to avoid pitfalls.

 

Friends who are considering purchasing diesel generator sets in the near future might want to take a serious look; it may indeed be useful. This article is compiled based on years of experience in the industry and is provided solely for your reference and learning.

 

Key Considerations When Selecting a Diesel Generator Set

 

Ⅰ. Power Matching (Most Critical)

 

1. Calculate Actual Load Power

- Distinguish between commonly used power PRP (continuous long-term operation) and standby power ESP (emergency short-term, only 1 hour/12 hours). Standby power cannot be used at full load for long periods.

- Consider load type: resistive (lighting, heaters) and inductive (motors, pumps, air compressors). Motor starting current is 3~7 times rated current, so starting margin must be reserved.

 

2. Redundancy Reserve

- Reserve 20%~30% margin for conventional scenarios; reserve 40% for multiple units in parallel or frequent starting of high-power equipment; avoid running the unit below 30% load for long periods (prone to carbon buildup and cylinder scuffing).

 

3. Single Unit or Parallel Units

- For large load fluctuations, uninterrupted power supply, or future expansion, choose multiple units in parallel; for stable load and simple standby, select a single unit.

 

II. Brands and Quality of Diesel Engines

1. Classification and Grade

- High-end imported - Mainstream domestic - Secondary and tertiary domestic

 

2. Key parameters to look at

- Displacement, number of cylinders, cooling method (mainly water-cooled, small portable units air-cooled), fuel consumption, emission standards (China II / China III / China IV; urban areas and engine rooms must meet emission standards).

 

III. Generator (Alternator) Configuration

 

1. Excitation Method

- Brushless synchronous generator: brushless, low failure rate, first choice for engine rooms and long-term backup;
- Brushed: lower price, suitable for short-term temporary use at construction sites.

 

2. Material

Full copper winding > half copper half aluminum > aluminum wire. Aluminum wire generates more heat and ages easily, not recommended for long-term use.

 

3. Voltage Regulation Accuracy

General type ±5%; precision equipment (servers, medical, instruments) requires high-precision AVR regulation of ±1%.

 

IV. Control System (Automation Level)

 

1. Basic Manual Panel: local start and stop, suitable for temporary power at construction sites, lowest cost.

2. Automatic ATS Dual Power Control Cabinet: automatically starts when mains power fails, automatically stops when power returns; essential for shopping malls, hospitals, data centers.

3. High-end Intelligent Module: remote monitoring, mobile app, parallel module, fault alarms (oil pressure, water temperature, overload, overspeed protection).

 

V. Usage Scenarios and Environment

 

1. Placement Types

- Open Rack: For use in machine rooms, low cost, good heat dissipation;

- Silent Box: Noise reduction for residential areas, hospitals, the noise level is 70~75dB;

- Mobile Trailer: Temporary power supply at construction sites or outdoors, with brakes and towing;

- Container Unit: High power, long-term outdoor use, integrated rainproof and noise reduction.

 

2. Environmental Conditions

- Altitude: For altitudes >1000m, the air is thin, so derating is required or a highland-specific model should be selected;

- Temperature: Increase cooling in high-temperature areas, use water-jacket heaters in severe cold;

- Dust/Humidity: For mines or seaside locations, choose dustproof and anti-corrosion models.

 

VI. Fuel, Fuel Consumption, and Operating Costs

 

1. Fuel Consumption Rate: The lower the fuel consumption at full load, the more cost-effective for long-term use. Compare with high-quality models around 200g/kWh.

2. Fuel Tank Configuration: Built-in small tanks for short-term use; for long-term operation, an external fuel storage system is required.

3. Maintenance Cost: Consider availability of compatible parts, prices of filter and oil consumables, and whether there are local after-sales service points.

 

VII. Safety and Emission Regulations

 

1. Emission Standards: Indoor urban areas and environmentally regulated zones must meet China III/IV standards, remote construction sites may use China II.

2. Safety Configuration: Automatic protection against overspeed, high water temperature, low oil pressure, overload, short circuit; machine rooms require smoke exhaust, heat insulation, and fire prevention treatment.

3. Noise Reduction and Smoke Exhaust: Residential areas must have mufflers and exhaust ducts to avoid noise disturbance.

 

VIII. Budget, After-sales Service, and Warranty

1. You get what you pay for: low-priced aluminum wires and refurbished machines save money in the short term but have more faults later; prioritize brand-new complete units.

 

2. Warranty period: whole machine 1–2 years, original factory power warranty is more reliable.

3. Local after-sales service: whether there are repair outlets locally, whether faults can be addressed quickly on-site, speed of spare parts supply.

 

IX. Additional Special Requirements

 

1. Uninterrupted power supply (UPS linkage): match startup time (≤8s);

 

2. Anti-corrosion requirements: use stainless steel parts and anti-corrosion coatings for coastal chemical plants;

 

3. Low-temperature areas: install preheating devices and antifreeze systems.