curl --request POST \
  --url https://api.iotools.cloud/v1/tool/transformer-sizing-calculator \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "connectedLoadKw": "150",
  "demandFactor": "80",
  "loadPowerFactor": "0.85",
  "growthMargin": "20",
  "system": "three",
  "voltage": "400"
}
'

{
  "tool": "transformer-sizing-calculator",
  "tool_version": "1.0.1",
  "outputs": {
    "results": [
      {
        "quantity": "Connected load",
        "value": "150 kW"
      },
      {
        "quantity": "Demand load (80% demand factor)",
        "value": "120 kW"
      },
      {
        "quantity": "Required apparent power (at PF 0.85)",
        "value": "141.176 kVA"
      },
      {
        "quantity": "With growth margin (20%)",
        "value": "169.412 kVA"
      },
      {
        "quantity": "Recommended standard transformer size",
        "value": "200 kVA"
      },
      {
        "quantity": "Secondary full-load current at recommended size",
        "value": "288.675 A"
      }
    ],
    "breakdown": "Demand load = Connected load × demand factor = 150 × 0.8 = 120 kW\nRequired kVA = Demand load ÷ power factor = 120 ÷ 0.85 = 141.176 kVA\nWith growth margin = Required kVA × (1 + margin) = 141.176 × 1.2 = 169.412 kVA\nRecommended size: next standard rating ≥ 169.412 kVA → 200 kVA\nI = kVA × 1000 ÷ (√3 × 400 V)\nPreliminary sizing only — inrush current, ambient/altitude derating, harmonics and utility approval need an engineering review."
  },
  "credits_used": 3,
  "credits_remaining": null
}