SDEC 6KTAA25-G31 vs Yuchai YC6TH1070-D31: 50 Hz generator ratings compared
Compare the documented apparent-power ratings before choosing a generator package. These documents support a kVA comparison; they do not support treating both engines as identical 720 kWe sets.
Quick comparison: matching documented ratings
Diesel · 50 Hz. Figures refer to the identified source configurations, not Haifeng test results. Confirm the exact build and site conditions before selection.
| Rating basis | SDEC 6KTAA25-G31 | Yuchai YC6TH1070-D31 |
|---|---|---|
| Standby · 50 Hz | 900 kVA | 887.5 kVA |
| Prime · 50 Hz | 800 kVA | 812.5 kVA |
Source scope and checks before selection
- The SDEC brochure lists kVA, not the catalog’s 655 kWe prime figure. No kWe conversion is made in this comparison.
- Yuchai ZJ/YC3500050 page 2 lists 710 kWe standby, whereas the catalog lists 720. Source values are used here.
- Confirm reference conditions and the exact quoted package. The SDEC brochure is a 2020 document; current availability and approved configuration need supplier confirmation.
Which should you shortlist?
For prime operation, the documents list 800 kVA for SDEC and 812.5 kVA for Yuchai. Their standby order is reversed: 900 and 887.5 kVA. This small difference is a reason to check the duty and actual load, not to name an overall winner. Confirm the required real power and power factor with the generator supplier.
Three checks before requesting a quote
- Match the operating duty. Keep standby backup separate from prime variable-load operation. These 50 Hz ratings do not establish output at 60 Hz.
- Check the complete package: voltage, alternator, load steps, ambient temperature and altitude. Ask for the resulting site rating and test scope.
- Confirm support and documentation: exact engine suffix, serial-specific parts information, available service documents and destination-specific emissions evidence. A catalog label alone does not prove compliance.
Sources and comparison method
Reviewed 21 October 2026. This is a document and catalog comparison by Haifeng Machinery, an equipment supplier. Matching fuel, frequency and duty does not establish identical reference conditions or interchangeability. No independent test, price, stock or reliability ranking is claimed.
- SDEC manufacturer brochure — technical parameters, printed pages 06–07
Open the attached SDEC brochure: 6KTAA25-G31 row, 800 kVA prime / 900 kVA standby at 50 Hz.
- Yuchai ZJ/YC3500050 — page 2
Attached model sheet: 812.5 kVA prime / 887.5 kVA standby, 50 Hz at 1,500 rpm; stated power factor 0.8.
Can one replace the other?
A similar electrical rating is only a starting point. Mounting, coupling, cooling, controls, emissions and site requirements need a package-level review. Send the existing generator model or nameplate with your question.
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