⚡ CircuitSecrets
Motor Capacitor · Breaker · Cable
Single-phase AC motor full system calculator — start/run capacitor, breaker sizing, cable selection, voltage drop & derating per IEC standard
Start Cap
Run Cap
MCB/MCCB
Cable Size
Voltage Drop
IEC 60364
Startup Torque
Start Capacitor Input
Motor Power
Supply
Load Type
Start Cap Result
Capacitor Sizing
Start Capacitor
—
µF (nearest standard)
► Formula
Start Cap Sizing
C = Factor × HP × (120/V)² × (60/f)
V_cap = 1.5 × V_supply (min)
I_FLC = P / (V × η × PF)
Type: Electrolytic, short duty only
Continuous Duty
Run Capacitor Input
Motor Power
Supply & PF
Run Cap Result
Capacitor Sizing
Run Capacitor
—
µF (nearest standard)
► Formula
Run Cap — PF Correction
kVAr = P × (tan φ₁ − tan φ₂)
C = kVAr×10⁶ / (2π×f×V²)
Rule: ~3 µF/HP @ 220V 50Hz
V_cap ≥ 440V continuous duty
IEC 60364
System Input
Motor
Cable & Installation
System Result
Full Analysis
Motor
—
▶
Breaker
—
▶
Cable
—
▶
Load
—
Full Load Current
—
Amperes (FLC)
► Formulas
Motor System Sizing (IEC)
I_FLC = P / (V × η × PF)
I_design = I_FLC × start_factor
Breaker = next standard ≥ I_design
Cable = I_cap / derating ≥ I_FLC
V_drop = 2×I×ρ×L / A (%)
Derating: temp + grouping × install
⚠ Note: Results are engineering estimates per IEC guidelines. Always verify against motor nameplate, local wiring regulations and installation conditions. Consult a qualified engineer for critical installations.
