Zhongxin General is a China-based manufacturer, factory, and supplier of 50 kVA three-phase outdoor oil-immersed distribution transformers — model S20-M-50/10, stepping 10 kV down to 400 V with Dyn11 vector group and ONAN cooling. This is the smallest capacity in our full oil-immersed distribution range, widely specified for rural electrification, single small commercial loads, telecom base stations, agricultural pumping stations, and remote or low-density distribution points where a full-size 100 kVA or larger unit would be oversized for the actual load.
Technical Specifications
| Parameter | Value |
|---|---|
| Product Type | Power Transformer |
| Model | S20-M-50/10 |
| Product Code | 1ZX.710.7005A |
| Phases | 3-Phase |
| Connection Symbol | Dyn11 |
| Insulation Level | LI75 AC35 / LI AC3 |
| Standards | GB1094.1, 2-2013, GB20052-2024, GB/T 6451-2023, GB1094.3-2017 |
| Rated Frequency | 50 Hz |
| Service Conditions | Outdoor |
| Cooling Mode | ONAN |
| Short-Circuit Impedance | 3.93% |
| Tap Position I | HV: 10500 V |
| Tap Position II (Rated) | HV: 10000 V / 2.89 A — LV: 400 V / 72.2 A |
| Tap Position III | HV: 9500 V |
| Lifting Weight of Active Part | 235 kg |
| Weight of Insulating Oil | 85 kg |
| Total Weight | 390 kg |
| Manufacturer | Sichuan Zhongxin General Electric Co., Ltd. |
The nameplate parameters above are taken directly from the actual S20-M-50/10 unit manufactured at Zhongxin General’s Sichuan facility. Every parameter is verified through routine factory acceptance testing before dispatch.
This product complies with GB 20052-2024 energy efficiency requirements at the standard grade. We can also produce Grade 1 energy efficiency versions whose technical standards are equivalent to or higher than the relevant provisions of COMMISSION REGULATION (EU) No 548/2014 and Commission Regulation (EU) 2019/1783 of 1 October 2019. Aluminium winding versions are available on request as an alternative to the standard copper winding configuration.
Manufacturing Process — From Winding to Dispatch
At 50 kVA, the unit is compact, but the manufacturing discipline behind it is identical to every other capacity Zhongxin General produces. Every image below documents the actual 50 kVA unit — this specific capacity, wound, assembled, oil-filled, and tested at our Sichuan factory. Unlike suppliers who illustrate their smallest-capacity listings with photographs of a larger transformer standing in for it, what you see here is exactly what is manufactured and shipped at this rating.
The high-voltage winding uses enamelled copper wire wound to precise turn counts, with oil-impregnated insulating paper between layers, sized to deliver the rated 3.93% short-circuit impedance shown on the nameplate. The low-voltage winding is dimensioned to carry the rated LV current of 72.2 A at tap position II without exceeding design temperature rise.
Lead Wire Arrangement
Tap Changer Installation
Tank Assembly
The wound and tap-changer-fitted active part is lowered into its corrugated fin tank. At 50 kVA, the corrugated fin design provides sufficient surface area for fully passive ONAN cooling — no separate radiator banks are required at this capacity, keeping the finished unit compact and lightweight at a total weight of just 390 kg.
Oil Filling
Insulating oil — 85 kg per unit at this capacity — is filled through the multifunctional tubular oil level gauge, which allows visual confirmation of fill level throughout the process and continues to serve as the in-service oil level indicator after commissioning. Oil filling is carried out under controlled conditions to avoid moisture ingress and trapped air, both of which would compromise dielectric strength.
Assembly Complete
With oil filling complete and all fittings — conservator, breather, oil level gauge, pressure relief device — installed, the 50 kVA unit is fully assembled and ready to proceed to the test bay.
Factory Acceptance Testing
No 50 kVA transformer leaves our factory without a complete routine test programme. Test reports are issued as standard documentation with every order — not provided only on request.
Finished Product Detail
The low-voltage and high-voltage terminal photographs above show the actual bushing layout and creepage/clearance spacing on the finished 50 kVA unit — useful reference for engineers planning busbar or cable termination on site. The top-view photo shows the conservator tank, magnetic oil level gauge, and breather assembly that keep the main tank oil sealed from atmospheric moisture during service.
Why Zhongxin General — Our Advantages Over Other Suppliers
Real product photographs at the actual capacity. Every image on this page shows the 50 kVA unit itself — from winding through to finished product. It is common in this industry for suppliers to illustrate a small-capacity listing like 50 kVA with photographs of a 200 kVA, 500 kVA, or larger transformer, because they do not actually keep that capacity in regular production. Our production-line photographs give you verifiable evidence of what we manufacture and ship at 50 kVA — not a substitute image from a different product.
Complete capacity-range production tooling. Zhongxin General holds dedicated production tooling across the entire oil-immersed transformer range, from 30 kVA up through 100 MVA. The 50 kVA unit is wound and assembled with tooling matched to its specific dimensions — not adapted from a larger or smaller capacity — which keeps impedance values, dimensional tolerances, and delivery timelines consistent even at the smallest end of our range.
Full in-house production cycle. Winding, active part assembly, tap changer fitting, tank assembly, oil filling, and factory acceptance testing are all performed at our Sichuan facility. No outsourcing of critical manufacturing steps, regardless of order size.
All energy efficiency grades available. We produce Grade 1, Grade 2, and Grade 3 versions to GB 20052-2024. Our Grade 1 units meet and exceed EU Commission Regulation No. 548/2014 and 2019/1783 Tier 1 and Tier 2 requirements, backed by CE Declaration of Conformity documentation for international projects.
Copper and aluminium winding both available. As a manufacturing factory rather than a trading company, we offer both winding configurations to match project budget and specification requirements — an option trading companies and agents typically cannot meaningfully offer without direct factory involvement.
No minimum order penalty on small-capacity units. Because the 50 kVA unit has its own dedicated tooling and is produced regularly as part of our standard distribution range, single-unit or small-batch orders are handled on normal production schedules — not treated as a special, low-priority run.
Full routine testing, every unit, test report as standard. No transformer leaves our factory without passing the complete routine test programme, regardless of capacity.
Applicable Standards & Testing
Every 50 kVA oil-immersed transformer manufactured by Zhongxin General undergoes a full routine test programme before dispatch.
Routine tests (every unit):
- Winding resistance measurement
- Voltage ratio and vector group verification
- No-load loss and no-load current
- Load loss and short-circuit impedance
- Induced overvoltage withstand test
- Separate-source AC withstand test
Type tests (reports available on request):
- Temperature rise test
- Lightning impulse test
Special tests (available on request):
- Partial discharge measurement
- Sound level (noise) measurement
- Short-circuit withstand test
All tests are conducted to IEC 60076 and GB 1094 / GB/T 6451. Factory Acceptance Test (FAT) with client witness is supported. Test reports and ITP documentation are provided as standard with every order.
Available Options & Configurations
- Winding material: copper (standard) or aluminium
- Voltage class: 6 kV, 10 kV, or 35 kV; HV customizable to match local grid standards
- Low voltage: 380 V, 400 V, 415 V, 433 V, or other values to match local grid
- Frequency: 50 Hz (standard) or 60 Hz
- Energy efficiency grade: GB 20052-2024 Grade 1, Grade 2, or Grade 3
- Tap changer: ±2×2.5% off-circuit (standard)
- Service conditions: outdoor (standard); indoor version available
- Oil type: mineral oil (standard); silicone oil for high-fire-safety environments available on request
- Nitrogen-sealed tank for long-distance sea freight
- Export wooden crating with full documentation package
Typical Applications
The 50 kVA oil-immersed distribution transformer is the standard choice for low-density distribution points: single rural households or small village clusters, telecom base stations, agricultural irrigation and pumping equipment, small roadside commercial units, construction site temporary power, and remote monitoring or signal stations where load demand does not justify a larger transformer. At 10 kV / 400 V with Dyn11 vector group and ONAN cooling, it serves as a compact, low-maintenance grid interface built to operate reliably for decades.
Shipping & Delivery
Our export experience spans Europe, Central Asia, South Asia, and Africa, developed through real projects including a 1250 kVA dry-type transformer export to Europe, a 5000 kVA step-up transformer for a Nepal hydropower station, and a prefabricated substation for Aktau Port, Kazakhstan. The same logistics and documentation processes apply to 50 kVA distribution transformer orders, whether shipped as a single unit or as part of a larger mixed-capacity batch.
Inquire About 50 kVA Oil-Immersed Transformer
Need a quotation, technical datasheet, or Factory Acceptance Test arrangement for the 50 kVA oil-immersed distribution transformer? Tell us your grid voltage, required LV output, frequency, efficiency grade, and any special environmental or installation conditions — and we will configure the right unit for your project.
Contact Us for Price & Datasheet
About Zhongxin General — Oil-Immersed Transformer Manufacturer & Factory
Zhongxin General (Sichuan Zhongxin General Electric Energy Co., Ltd.) is a China-based manufacturer and factory specialising in oil-immersed power transformers and dry-type power transformers, HV/MV/LV switchgear, prefabricated substations, and energy storage systems.
Headquartered in Xinjin District, Chengdu, Sichuan Province, the company holds National “Little Giant” Enterprise status — China’s highest SME innovation designation — alongside National High-Tech Enterprise certification. Our oil-immersed transformer portfolio covers 30 kVA to 100 MVA, configurable to 6 kV, 10 kV, 35 kV, 66 kV, 110 kV, and higher voltage classes, in both GB and IEC standard configurations for domestic and international projects. The 50 kVA oil-immersed distribution transformer described on this page is the entry-capacity point of our standard distribution range — supplied to rural distribution networks, telecom and agricultural power projects, and small commercial installations across China and international markets.
Every transformer we manufacture undergoes full routine testing to IEC 60076 or GB 1094 before dispatch. Test reports are issued as standard documentation with every order.
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