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Motor Calculator

NEC Article 430 (FLC tables, branch-circuit/OCPD/overload/disconnect sizing) or IEC general method — standalone, independent of any protection-relay motor tab.

AAJappsEngineering Calculation Report

Motor Calculator

NEC Article 430, IEC general method

Generated

For preliminary engineering use only — always verify results against project-specific standards and a qualified engineer's review before use in a real design.

FLC & branch-circuit sizing

Standard Basis

Phase

Motor Type

Horsepower (HP)

Voltage

SF≥1.15 or Temp Rise≤40°C?

Protective Device Type

Starting method & voltage-dip check

Starting Method

Locked-Rotor Current, LRA

System Voltage

Source SC Capacity

kVA

Max Allowable Voltage Dip

Multi-motor feeder sizing (NEC 430 Part V)

Description

FLC (A)

Wound-Rotor

Feeder-Level Device Type

IEC Design Margin Factor

FLC & branch-circuit result

Full-Load Current (FLC)34.0 A

Branch-Circuit Min. Ampacity42.5 A

Max Branch-Circuit OCPD60 A (or 70 A under the 430.52(C)(1)(b) exception)

Overload / Disconnect Setting39.1 A (disc. 39.1 A)

Starting & voltage-dip result

Effective Starting Current180.0 A

Starting kVA143.41 kVA

Calculated Voltage Dip2.788% (limit 15%) ✓

Multi-motor feeder result

Largest MotorLargest Motor

Feeder Min. Ampacity49.0 A

Feeder OCPD64 A