Calculation Formula for Dry-Type Transformer Power
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All electrical equipment has a certain power rating. The operating performance of a dry-type transformer relies on physical quantities such as power, and operating capacity is an important physical quantity and basic attribute of dry-type transformers. When selecting a dry-type transformer, whether its power rating is suitable should be determined according to production characteristics and main load conditions. In practice, we can calculate the required power of your dry-type transformer based on various factors and data.
Generally speaking, the power of a single-phase transformer is obtained by multiplying the total power by 120% (with efficiency calculated at 80%). So how do we calculate the power of a three-phase transformer? Engineers from dry-type transformer manufacturers provide the following four main methods (taking 220V phase voltage and 380V line voltage as examples):
1.Three-phase rated power = 1.732 × rated current × rated line voltage (380V) = 3 × rated current × rated phase voltage (220V).
2.For unbalanced three-phase loads, calculate based on three times the maximum phase power. For example, if Phase A is 9KW, Phase B is 10KW, and Phase C is 11KW, then P = 3 × 11 = 33KW.
3.The power factor of a transformer is typically 0.8 (sometimes 0.7). In the above example, total transformer power = 33 ÷ 0.8 = 41.25KW.
4.According to the Electrical Engineering Design Manual, for a single transformer with stable load, the transformer capacity is generally about 85% loaded. Therefore, in the above example, transformer capacity = 41.25 ÷ 85% ≈ 48.53KW, so a 50KVA transformer is selected.
The above four points are the power calculation formulas for dry-type transformers provided by the manufacturer. The power of a dry-type transformer is related to the performance of all its designed components. For dry-type transformers, more attention should be paid to quality and technology to ensure better power performance and improved operational results.
The above is the power calculation method for dry-type transformers, which you can use to calculate the power of the dry-type transformer you are using. Naturally, there may be slight deviations between actual power and calculated power; this is normal as long as it does not exceed national standards.
