Dry transformer weight: weight table by power 

The dry weight of a transformer is not just a number on a specification sheet. This is a critical parameter in the design of electrical substations, calculation of floor loads, selection of lifting equipment and delivery logistics. We have repeatedly encountered situations where insufficient weight assessment led to installation delays: the crane turned out to be weak, the site was unprepared, and the foundation was not designed for additional axial load. This article is a practical table of dry-type transformer weight by power, based on real data from serial products, including models produced by Wenzhou Qiaonasen Electrical Equipment Co.,Ltd.

Why mass is more important than it seems

Dry-type transformers do not contain oil, but this does not make them lightweight. The bulk of the weight comes from copper or aluminum windings and a steel magnetic core. At the same time, the mass grows nonlinearly: an increase in power by 50% can give a weight increase of 70–90%. For example, a 250 kVA transformer weighs about 480 kg, and a 630 kVA model already weighs 1150 kg. The difference of 670 kg requires a revision of all engineering solutions: from fastening with anchor bolts to calculating the deflection of the steel frame. We have seen projects where the calculation was carried out only by dimensions - and the consequences were expensive.

Dry transformer weight table by power (real values)

The data is given for three-phase transformers with voltage 6/0.4 kV or 10/0.4 kV, insulation class F/H, with natural air cooling (AN). All values are checked at the Wenzhou factory and confirmed by tests before shipment:

• 100 kVA— 320–360 kg
• 160 kVA— 410–450 kg
• 250 kVA— 470–510 kg
• 400 kVA— 680–730 kg
• 630 kVA— 1080–1150 kg
• 800 kVA— 1320–1400 kg
• 1000 kVA— 1550–1650 kg
• 1250 kVA— 1850–1950 kg
• 1600 kVA— 2280–2420 kg
• 2000 kVA— 2750–2900 kg

The variation within each line is explained by the design: transformers with copper windings are 18–22% heavier than their analogues with aluminum, and enhanced protection against moisture and dust (IP54/IP55) adds 3–5% of the weight due to sealed casings and sealed inputs.

What does “package weight” hide?

Clients often ask: “What is the weight of a dry transformer in a wooden frame?” The answer depends on the type of transportation. For sea containers we use multi-layer plywood with metal corners - this packaging adds 80-120 kg to the total weight. For ground delivery within Russia, a light wooden frame is used - +35–55 kg. Important: the packaged weight affects railway transportation tariffs and the permissible axle load on road trains. We always indicate both values ​​- “net weight” and “gross weight” - in the technical passport in Russian.

How to choose and not make a mistake

Simply taking a value from a table is not enough. Consider three factors:

• Operating conditions: in regions with high humidity or an aggressive environment (for example, the Kaliningrad region or port areas), we recommend transformers with windings coated with epoxy resin and steel with increased corrosion resistance - their weight is 4-6% higher than the basic models.

• Wiring diagram: if installation is planned at a height of more than 3 meters, you need a kit with lifting eyes and a reinforced base - +12–18 kg.

• Power reserve: ordering a transformer “back to back” is risky. Practice shows: the optimal reserve is 15–20%. But this means that when calculating weight you need to focus on the next row of the table, and not on the load rating.

Wenzhou Qiaonasen Electrical Equipment LLC provides free engineering weight calculations for a specific project - taking into account the climate, installation method and protection requirements. This saves time and eliminates errors at the approval stage.

Bottom line: weight is part of the engineering solution

The dry weight of a transformer is not a technical artifact, but a key element of a systems approach. It affects safety, service life, installation costs and even energy efficiency: a case that is too light can cause vibration and noise, and excess weight can overload the supporting structures. We work with clients so that the figure in the passport matches the reality on the construction site. Verified data, honest ranges, adaptation to Russian conditions - all this is available onqnasen.ru. If you need exact weight for a specific model, request a technical proposal. We will prepare it taking into account all your conditions.