Short circuit test of transformer

The short-circuit test of a transformer is a standard method used to determine its series parameters (mainly equivalent impedance).

Purpose of the Short-Circuit Test

• Determine:
• Copper losses at full load
• Equivalent series impedance (resistance and reactance)
• Voltage regulation

⚙️ How the Test Works

✅ Test Setup:

• One winding (usually the HV side) is short-circuited
• The other winding (usually LV) is connected to a variable AC supply
• Voltage is gradually increased until full-load current flows in the short-circuited winding

✅ Measurements Taken:

• Applied voltage Vsc (very low, ~5–10% of rated voltage)
• Input current Isc​ (rated current)
• Input power Psc (measured using a wattmeter)