CircuitSecrets Professional
Advanced Generator
Engineering Suite
Industrial-grade power system analysis tools for short circuit, motor starting, parallel operation, voltage regulation & protection sizing
IEEE Std 141
IEC 60909
IEEE Std 399
NEMA MG-1
IEC 60947-2
ISO 8528
Calculator 01 / 05 · IEEE Std 141 / IEC 60909
⚡ Generator Short Circuit Current
Calculate initial fault current & fault level based on subtransient reactance — essential for protection coordination & breaker selection
Short Circuit Analysis Results
► View Engineering Formulas
FLC (3Φ): (S_kVA×1000) / (√3×V) · FLC (1Φ): (S_kVA×1000) / V
I_SC: I_FL × (100 / Xd″%) · Fault MVA: √3 × V_kV × I_SC / 1000
Xd″ typical: 12–20% · IEEE Std 141 · IEC 60909
I_SC: I_FL × (100 / Xd″%) · Fault MVA: √3 × V_kV × I_SC / 1000
Xd″ typical: 12–20% · IEEE Std 141 · IEC 60909
Calculator 02 / 05 · IEEE Std 399 / NEMA MG-1
🔨 Motor Starting kVA Calculator
Required generator capacity for motor starting — accounts for inrush current & different starting methods for optimal sizing
Motor Starting Analysis Results
► View Engineering Formulas
kW from HP: HP × 0.746
I_FL: (P_kW×1000) / (√3×V×η×PF)
Starting multipliers: DOL 6× · Star-Delta 3× · Soft/VFD 2.5×
Required kVA: (I_start×√3×V/1000) × 1.25
IEEE Std 399 · NEMA MG-1
I_FL: (P_kW×1000) / (√3×V×η×PF)
Starting multipliers: DOL 6× · Star-Delta 3× · Soft/VFD 2.5×
Required kVA: (I_start×√3×V/1000) × 1.25
IEEE Std 399 · NEMA MG-1
Calculator 03 / 05 · IEEE Std 399 / ISO 8528-5
🔄 Parallel Load Sharing Calculator
Load distribution between parallel generators — prevents overloading & optimises fuel efficiency in multi-generator systems
Parallel Load Sharing Results
► View Engineering Formulas
Share Factor: f1 = G1/(G1+G2) · L1 = Load × f1
Loading %: (Shared Load / Generator Rating) × 100
Optimal: 70–85% · Imbalance: <10% Good · <20% OK
IEEE Std 399 · ISO 8528-5
Loading %: (Shared Load / Generator Rating) × 100
Optimal: 70–85% · Imbalance: <10% Good · <20% OK
IEEE Std 399 · ISO 8528-5
Calculator 04 / 05 · IEEE Std 141 / IEC 60034-1
📊 Voltage Regulation Calculator
Voltage regulation under load — for power quality analysis, equipment compatibility & AVR sizing
Voltage Regulation Results
► View Engineering Formulas
%Z: √(%R²+%X²) · k = Load%/100
Lagging: k×[%R×cosφ+%X×sinφ]
Leading: k×[%R×cosφ−%X×sinφ]
Limits: ≤3% Excellent · ≤5% Acceptable · >5% Poor
IEEE Std 141 · IEC 60034-1
Lagging: k×[%R×cosφ+%X×sinφ]
Leading: k×[%R×cosφ−%X×sinφ]
Limits: ≤3% Excellent · ≤5% Acceptable · >5% Poor
IEEE Std 141 · IEC 60034-1
Calculator 05 / 05 · IEC 60947-2 / NEC Article 430
🛡️ Protection Sizing Calculator
Circuit breaker ratings & breaking capacity for generator protection — fault interruption capability & coordination compliance
Protection Sizing Results
► View Engineering Formulas
Breaker Rating: ≥1.25 × I_FL (NEC 430.52)
Fault Current: I_FL × (100 / Xd″%)
Breaking Capacity: I_fault × 1.5 (safety factor)
MCB: ≤125A / 10kA · MCCB: ≤3200A / 100kA
ACB: ≤6300A / 150kA · VCB: ≤5000A / 100kA
IEC 60947-2 · IEEE C37.13 · NEC Art. 430
Fault Current: I_FL × (100 / Xd″%)
Breaking Capacity: I_fault × 1.5 (safety factor)
MCB: ≤125A / 10kA · MCCB: ≤3200A / 100kA
ACB: ≤6300A / 150kA · VCB: ≤5000A / 100kA
IEC 60947-2 · IEEE C37.13 · NEC Art. 430
⚠️ Professional Engineering Disclaimer: These calculators provide engineering estimation only for preliminary analysis. All calculations must be verified with actual generator datasheets, manufacturer specifications, and compliance with local electrical standards (NEC, IEC, IEEE). For critical installations and final design, consult licensed professional electrical engineers and conduct comprehensive system studies. CircuitSecrets assumes no liability for design decisions or operational outcomes based on these calculations.
