Distribution transformers are sized according to which rating?

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Multiple Choice

Distribution transformers are sized according to which rating?

The main idea is that distribution transformers are sized by their power capability, measured in kVA (apparent power). The VA rating defines the maximum continuous current the windings and cooling can handle at the rated voltage and frequency without overheating. Because heating depends on current, not just voltage, the VA rating gives a combined measure of voltage and current that determines size. In use, the actual real power you can deliver depends on the load’s power factor: a 75 kVA transformer at a 0.8 power factor can supply about 60 kW, since real power = kVA × power factor. The voltage rating matters for the system voltage the transformer is designed to work with, and polarity or phase angle relate to connections and power quality, but they don’t set the transformer's size. So the correct answer is the KVA rating.

The main idea is that distribution transformers are sized by their power capability, measured in kVA (apparent power). The VA rating defines the maximum continuous current the windings and cooling can handle at the rated voltage and frequency without overheating. Because heating depends on current, not just voltage, the VA rating gives a combined measure of voltage and current that determines size. In use, the actual real power you can deliver depends on the load’s power factor: a 75 kVA transformer at a 0.8 power factor can supply about 60 kW, since real power = kVA × power factor. The voltage rating matters for the system voltage the transformer is designed to work with, and polarity or phase angle relate to connections and power quality, but they don’t set the transformer's size. So the correct answer is the KVA rating.

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