Diesel Generator Set | Full Version | Buying Guide | Latest 2026 Edition

Diesel Generator Set | Full Version | Buying Guide | Latest 2026 Edition

 

1. First, distinguish the purpose: main use / backup, never choose the wrong power rating

 

1) Purpose definition (where 90% of people go wrong)

 

- Main power supply (24h continuous generation, construction site / remote areas without grid electricity)

 

Continuous power PRP = total load × 1.1; can run continuously for unlimited hours

 

- Backup emergency (hospitals / factories / property management, used only during power outages)

 

Standby power = critical load × 1.2; only allows 1 hour of full load within 12 hours

 

⚠️ It is strictly forbidden for the backup generator to run continuously long-term, as this burns the engine and greatly shortens its lifespan

 

2) Power calculation (must see for motor loads)

 

- Resistive load (lights, heating): 1:1 calculation

- Inductive load (water pumps / fans / air compressors): starting current is 3–7 times, must provide extra margin

- Unit conversion: 1 kVA ≈ 0.8 kW, don't be misled by sellers inflating kVA ratings
- Simple formula: total electricity kW × 1.3 = recommended generator kW

 

 

3) Altitude / temperature correction

 

- Power decreases 8%–12% for every ↑1000m in altitude, fuel consumption increases

- High temperature >40°C, also derate power and increase cooling capacity

 

2. How to choose an engine (the heart · determines fuel consumption and lifespan)

 

Prioritize major domestic brands: high cost-performance ratio (backup for construction sites/factories)

 

- King of cost-performance, very cheap spare parts, fuel-efficient, full range 20–800kW, first choice for civilian use

 

- Heavy-duty and durable, for long-term load in mines/industry, long lifespan

 

- Quiet, preferred for hospitals, hotels, and residential areas

 

If the budget allows, consider imported brands (data centers/hospitals/uninterruptible key loads)

 

3. Generator (do not buy aluminum-core)

- Must choose full copper brushless motor, aluminum core heats up quickly, easy to burn, unstable voltage, high failure rate

 

- Voltage regulation accuracy: ≤±0.5%, precision equipment (UPS/servers) ≤3% harmonic distortion

 

- Insulation class H, AVR automatic voltage regulation, domestic standard 380V three-phase/50Hz

 

4. Generator set type selection (according to site)

 

- Open frame: cheap, good heat dissipation, noisy → factories/outdoors

 

- Silent box type: ≤65 dB → residential areas, hospitals, hotels, urban areas

 

- Mobile trailer: temporary construction site, outdoor mobile power supply

 

- Fully automatic ATS cabinet: automatically starts within 10 seconds of power outage, essential for unattended operation

 

5. Control system configuration

 

- Basic: manual start/stop, voltage/water temperature/oil pressure protection

 

- Advanced: ATS automatic switching, parallel and grid connection, remote monitoring, mobile app

 

- Choose high-quality brands for guaranteed reliability

 

6. Cooling & accessories

 

- <50kW: air-cooled, cheap and simple

 

- ≥50kW: water-cooled, stable, high temperature resistant, essential for long-term operation

 

- Standard: fuel tank base (≥8h endurance), silencer, battery, protection

 

- Optional: low temperature preheating, external large fuel tank, rain shelter, noise reduction engineering

 

7. Warranty & after-sales service (most important)

 

- Industry standard: whole machine 1 year/1000 hours, whichever comes first

 

- Major brands: 2 years/2000 hours nationwide warranty

 

- Must have local service points, 24h on-site repair, spare parts in stock, no waiting

 

8. Pitfall Blacklist (Absolutely Do Not Buy)

 

1. Falsely labeled power: using kVA to pretend to be kW, small machines labeled with large power

 

2. Refurbished machines, assembled from miscellaneous brand engines, no certification

 

3. Aluminum-wrapped copper motors, low-quality miscellaneous brand controllers

 

4. Do not indicate rated/standby power, confusing the concepts

 

5. No ATS, no full set of overload/water temperature/oil pressure protection