kVA Tools logokVA ToolsBETA Autotransformer Kit


Input — System Configuration

Phase Configuration
Connection
Application
Source Voltage VH (V)
Output Voltage VL (V)
Desired Transformer Type
Load Demand
Power Factor (0 – 1.0)

Output — kVA Sizing

Parameter Value
Transformation Ratio (a = VH / VL)
Voltage Difference ΔV (V)
Load (Throughput) kVA
Series Winding kVA (Peq) — sizing basis
Common Winding kVA (Peq)
Conductive kVA (Pe) — electrical bypass
Recommended Standard Size

Output — Terminal Currents

Parameter Value
Source Current Iprimary (A)
Load Current Isecondary (A)
Series Winding Current Iseries (A)
Common Winding Current Icommon (A)
Primary Side Overcurrent Protective Device (OCPD) — NEC 450.6(A)
125% / 167% of Isource (≥9 A / <9 A)
Max Primary OCPD Size