Transformer Model Number Decoder
Paste a transformer model number — such as S13-M-1000/10 or SCB13-1250/10/0.4 Dyn11 — and decode its type, loss level, capacity, voltage and connection group.
Result
Enter your load → get a full design & BOM in seconds
Sample output| Parameter | Value |
|---|---|
| Type | Three-phase oil-immersed transformer (fully sealed) |
| Phases | Three-phase |
| Efficiency level | Loss level 13 (S13/SCB13 — grade 3, high efficiency) |
| Rated capacity | 1000 kVA |
| HV winding voltage | 10 kV |
| Winding material | Copper (default — confirm on nameplate) |
| Tap changer | Off-circuit / no-load tap changer |
For procurement engineers, specifiers and technicians who need to read the meaning encoded in Chinese and IEC transformer model designations.
Use the calculator
Worked example
A pre-computed reference example (crawlable — no JavaScript required). Enter your own parameters above for a live result.
Example 1 — S13-M-1000/10 (oil-immersed, grade 2)
| Parameter | Value |
|---|---|
| Type | Three-phase oil-immersed transformer (fully sealed) |
| Phases | Three-phase |
| Efficiency level | Loss level 13 (S13/SCB13 — grade 3, high efficiency) |
| Rated capacity | 1000 kVA |
| HV winding voltage | 10 kV |
| Winding material | Copper (default — confirm on nameplate) |
| Tap changer | Off-circuit / no-load tap changer |
Example 2 — SCB13-1250/10/0.4 Dyn11 (dry-type)
| Parameter | Value |
|---|---|
| Type | Three-phase cast-resin dry-type transformer |
| Phases | Three-phase |
| Efficiency level | Loss level 13 (S13/SCB13 — grade 3, high efficiency) |
| Rated capacity | 1250 kVA |
| HV winding voltage | 10 kV |
| LV winding voltage | 0.4 kV |
| Connection group | Dyn11 (delta HV / star LV, LV neutral, 30° lag) — standard distribution |
| Winding material | Copper (default — confirm on nameplate) |
| Tap changer | Off-circuit / no-load tap changer |
How it was calculated
- · Prefix letter: S = three-phase oil-immersed, D = single-phase, SCB/SG = dry-type (cast-resin / air).
- · Loss-level digit: 9/10/11/13/15/18/20/22 = efficiency grade (higher = lower loss).
- · Suffix letters: M = fully sealed, Z = on-load tap changer, L = aluminium winding.
- · Numbers: capacity/HV[/LV] in kVA and kV.
- · Trailing group: Dyn11, Yyn0, YNd11, etc.
Referenced standards
| Standard | Scope |
|---|---|
| GB/T 6451 | Technical parameters and requirements for oil-immersed power transformers |
| JB/T 3837 | Method for compilation of transformer product model designations |
| GB/T 10228 | Technical parameters and requirements for dry-type power transformers |
Frequently asked questions
What does S13-M-500/10 mean in a transformer model?
S = three-phase oil-immersed, 13 = loss/efficiency grade, M = sealed (full-sealed) construction, 500 = capacity in kVA, 10 = HV voltage in kV. So it is a 500 kVA, 10 kV sealed oil-immersed S13 Transformer. The calculator decodes the full model string.
What does SCB13-1000/10 mean?
SCB = three-phase dry-type cast-resin, 13 = loss grade, 1000 = capacity in kVA, 10 = HV voltage in kV. The 'B' denotes foil/band Winding. It is a 1000 kVA, 10 kV cast-resin Dry-Type Transformer. The calculator decodes SCB, SC, SG and other prefixes.
How do I read a transformer connection group like Dyn11?
Dyn11 = HV delta (D), LV wye/star (y) with neutral (n), and an 11 o'clock phase shift meaning LV lags HV by 30 deg (11 x 30 = 330 deg lead). Yyn0 = star/star with neutral and 0 deg shift. The calculator explains the Vector Group in the decoded result.
What do the letters S9, S11, S13, S20, S22 mean?
These are Chinese oil-immersed transformer series by loss level: S9 is the legacy standard, S11 and S13 reduce no-load loss ~20-30% step by step, and S20/S22 meet the current GB 20052 grade-1/2 efficiency. Higher numbers = lower losses and higher price. The calculator maps the series to its efficiency grade.
Why do I need to decode a transformer model number?
The model number encodes type, cooling, capacity, voltage and loss grade in a compact string, so decoding it lets you verify a quote, compare tenders, or match a replacement. Misreading a digit can lead to a wrong-voltage or wrong-capacity purchase. The calculator decodes the string into plain fields.
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Results are engineering estimates for preliminary design and reference only. Always verify with the applicable standards, the equipment nameplate and a licensed engineer before procurement or installation.
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