XIAOPAI · Wenzhou Xiaopai Electric Power Technology Co., Ltd. · Zhejiang, China
A dry type transformer manufacturer China buyers meet at a trade fair will usually open with a model code. SC(B)9-1000/35 is six facts, and for an imported unit those six facts are what the purchase order, the shipping plan and the commissioning report all have to agree on.THE CODE IS SIX FACTS
S is three-phase. C means the windings are cast in epoxy resin. The (B) marks a foil-type low voltage winding. The 9 is the performance level, which is where the loss figures come from. The box after the dash is rated capacity in kVA, and the 35 is the voltage class in kV. So SC(B)9-1000/35 reads as a three-phase cast-resin unit with foil LV windings, performance level 9, rated 1000 kVA at 35 kV. Cast-resin construction is the reason the letter C sits there instead of an O, and the difference matters at the port as much as at the site.DRY MEANS NO OIL, AND THAT CHANGES THE SITE
The windings are encapsulated in epoxy resin, so the unit is non-flammable, fire resistant and does not need oil containment. There is no oil to test, no conservator to watch and no bunding to build. The XIAOPAI document states the unit is intended for indoor installation, and that is a site condition rather than a shipping condition. Inside the tank-free design, the core uses imported cold-rolled grain-oriented silicon steel with mitre joints. It is bound with F-class tape and coated with epoxy, which the document links to lower no-load current and lower core noise. The high voltage winding is vacuum cast in filled epoxy, with glass fibre grids inside and outside the coil. The low voltage winding is foil, with DMD resin prepreg between layers and axial cooling ducts. Foil versus wire on the LV side is a specification decision with its own trade-offs, and it is visible in the model code rather than buried in a drawing. Choosing between dry and liquid-filled usually turns on the room, not on the load.THE LOSS COLUMN IS MEASURED AT 120 DEGREES
The published table runs from 30 to 2500 kVA at 6.0 percent impedance. At 30 kVA, no-load loss is 0.35 kW and on-load loss is 0.85 kW. At 2500 kVA the same columns read 5.00 kW and 21.5 kW. The header says the on-load figure is at 120 degrees Celsius. That single detail decides whether a comparison is fair. A liquid-filled unit is normally stated at 75 degrees, so putting the two numbers side by side without the reference temperature compares nothing. Heat build-up in a dry unit is managed by insulation class and by air, not by a tank of oil. Read the table as ratios and it says something useful about sizing. No-load loss is 1.17 percent of rating at 30 kVA and 0.20 percent at 2500 kVA. On-load loss falls from 2.83 percent to 0.86 percent over the same range. Small dry units carry proportionally heavier losses, and a project built from many small units will show it. No-load current runs from 2.8 percent down to 1.4 percent. Partial discharge is the other figure a buyer should see on the test record, because a cast coil either has voids or it does not.TWO WEIGHTS, ONE HEIGHT, AND THE SHIPMENT
The table gives two weight columns: 680 kg body weight at 30 kVA against 730 kg with the enclosure, and 6930 kg against 7030 kg at 2500 kVA. Those two numbers have different jobs. Body weight is what the lifting equipment and the floor see; the difference between the columns is what the crate and the enclosure add. Dimensions move the same way. A 30 kVA unit measures 1070 by 890 by 1050 mm on a 660 mm centre. A 1000 kVA unit measures 2020 by 1150 by 2040 mm on 1070 mm. A 2500 kVA unit reaches 2200 by 1150 by 2600 mm. Height is the number that catches people. The range goes from 1050 mm to 2800 mm, and the tall end is decided by the rating, not by the shipping method. Booking freight before the outline drawing is confirmed is how a unit ends up travelling with its enclosure removed. One mismatch is worth flagging. The dimension table continues to 6300 kVA at 2980 by 1700 by 2800 mm, while the loss table stops at 2500 kVA. If a project needs anything above 2500 kVA, ask for the loss figures in writing instead of extrapolating the last row.THE ENCLOSURE IS A SEPARATE SPECIFICATION
Protection degree is an option, not a default: IP20 and IP23 are both listed. Enclosure material is cold-rolled steel or stainless steel. Low voltage outgoing is a standard busbar, with side or top entry, and the document allows a custom exit pattern. For an import file this is the part that gets lost between the transformer and the switchgear. The IP rating, the cable entry direction and the enclosure material have to be settled before the outline drawing is issued, because all three change the dimensions and the weight on the packing list.140 PERCENT AND THE FAN BANK
The unit is rated to run at 140 percent of rated load for long periods under air cooling, and the cooling system uses cross-flow top-blown fans chosen for low noise and high air pressure. Fans are a maintenance item and a noise source, and both belong in the site plan rather than in the commissioning week. Noise control starts with where the unit sits, and sound level measurement has a standard method that both parties can point at. The temperature controller adds fault alarm, over-temperature alarm, over-temperature trip and a black box record, with an RS485 interface for central monitoring. If the plant runs a SCADA system, that interface is a line in the specification, not a bonus.SERVICE CONDITIONS ARE A CONTRACT TERM
The document states the limits plainly: installation altitude up to 1000 m, maximum ambient plus 40 degrees Celsius, maximum daily average plus 30, maximum annual average plus 20, minimum minus 30, indoor use. An overseas site outside any of those limits is a different transformer, not a footnote. Altitude affects insulation coordination, and ambient affects the loading curve. A buyer in a hot climate or at altitude should raise it before the order, and the supplier should answer in writing.THE EXPORT PACK AND THE DOCUMENT SET
Packing is stated as standard export packing, and the ports of loading are Shanghai and Ningbo. An importer working with a dry type transformer manufacturer China for the first time usually finds the gap at this point, between a correct unit and a complete file. Those two lines are the ones an importer actually plans around, because they fix the inland leg and the ocean leg before any technical question is settled. On the technical side, the file should carry five items. The outline drawing with L, W, H and centre dimensions. The loss table at its stated reference temperature. The weight with and without the enclosure. The IP rating. And the routine test record. Routine tests and power factor checks at commissioning are where those numbers get confirmed, and the pre-energisation checklist is shorter when the file arrived complete.WHAT XIAOPAI SUPPLIES
XIAOPAI manufactures the SC(B)9 cast-resin range from 30 to 2500 kVA at 35 kV, with 0.4 to 15 kV on the low side and Dyn11, Yyn0, Yd11 or YNd11 connections. The cast-resin dry-type range runs from SC(B)9 to SC(B)13, and the oil-immersed range at the same voltage class covers the sites where a liquid-filled unit is the better answer. Wenzhou Xiaopai Electric Power Technology Co., Ltd. handles the export documents, the outline drawings and the test records from Wenzhou, and ships through Shanghai and Ningbo. XIAOPAI keeps the model code, the loss table and the dimension table on the same page for each range, so an importer can build the file before the container is booked. That is the practical test of a dry type transformer manufacturer China buyers can rely on: the code, the weights and the port all match the paperwork, and nothing has to be asked twice.ONE LINE FOR THE RECORD
SC(B)9-1000/35 is three-phase, cast resin, foil LV, performance level 9, 1000 kVA, 35 kV, and the loss figure only compares once both columns are read at the same reference temperature.
