Advanced Motor Calculator – Starting Current, Protection, Torque & Slip | CircuitSecrets

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Advanced Motor Calculator — Phase 2

⚡ IEEE / IEC / BS Compliant

🔧 Common Motor Parameters

Enter motor nameplate data — shared across all calculators

Rated Power (kW)

Supply Voltage (V) 230 V 400 V 415 V 440 V 690 V 3300 V (MV) 6600 V (MV) 11000 V (HV)

Phases 3-Phase 1-Phase

Power Factor

Efficiency (%)

No. of Poles 2 Poles (3000 RPM) 4 Poles (1500 RPM) 6 Poles (1000 RPM) 8 Poles (750 RPM)

Supply Frequency (Hz) 50 Hz 60 Hz

Rated Speed (RPM)

⚡ Starting Current Parameters

Starting Method DOL (Direct On-Line) Star-Delta (Y-Δ) Autotransformer 50% Autotransformer 65% Autotransformer 80% Soft Starter VFD / Inverter

Locked Rotor Multiplier (× FLC)

Source Impedance (mΩ)

Cable Length (m)

🛡️ Protection Device Parameters

Motor Service Factor 1.00 (Standard) 1.15 (General Purpose) 1.25 (Heavy Duty)

Starting Duration Light (< 5 sec) Normal (5-15 sec) Heavy (15-30 sec) Very Heavy (> 30 sec)

Ambient Temperature (°C)

Cable Insulation PVC (70°C) XLPE (90°C) EPR (90°C)

Installation Method Cable Tray (Perforated) Conduit Direct Buried Cable Ladder

Grouping Factor (No. of Circuits) 1 Circuit (1.0) 2 Circuits (0.80) 3 Circuits (0.70) 4-6 Circuits (0.65) 7-9 Circuits (0.60)

⚙️ Torque Parameters

Motor Design Type NEMA B / IEC N (General Purpose) NEMA A (High Starting Torque) NEMA C / IEC H (High Starting Torque) NEMA D (Very High Starting Torque)

Load Type Fan / Blower Centrifugal Pump Compressor Conveyor Crusher / Mill

Driven Speed (RPM)

Gear Ratio (x:1)

🔄 Slip Calculation Parameters

Measured / Actual Speed (RPM)

Load Condition (%)

📊 VFD vs DOL — Energy & Cost Analysis

Operating Hours (hrs/day)

Operating Days (days/year)

Electricity Cost ($/kWh)

Average Load (%)

Average Speed Requirement (%)

VFD Cost (Installed) ($)

Application Type Variable Torque (Fan/Pump) Constant Torque (Conveyor)

VFD Efficiency (%)

⚠️ Engineering Disclaimer: This calculator is for estimation purposes only. Always verify with motor nameplate data and comply with local electrical codes (IEC 60034, IEC 60947, IEEE 112, NEC Article 430, BS 7671). Results include standard safety margins but site-specific conditions (altitude, harmonics, ambient derating) may require additional engineering review. Consult a qualified electrical engineer for final design.

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