Calculator Inputs
Example Data Table
| Load | Rated kW | Qty | Util | Div | Eff | PF | Hours/day | Start mult. |
|---|---|---|---|---|---|---|---|---|
| Temporary lighting | 8.0 | 1 | 0.80 | 0.90 | 0.95 | 0.95 | 10 | 1.0 |
| Welding sets | 6.0 | 2 | 0.60 | 0.70 | 0.90 | 0.85 | 6 | 1.2 |
| Dewatering pumps | 7.5 | 2 | 0.75 | 0.80 | 0.88 | 0.82 | 8 | 3.0 |
| Ventilation fans | 5.5 | 2 | 0.70 | 0.80 | 0.90 | 0.85 | 8 | 2.5 |
| Site offices & IT | 5.0 | 1 | 0.70 | 0.90 | 0.95 | 0.95 | 10 | 1.0 |
The calculator will compute adjusted kW, kVA, current, and generator sizes.
Formula Used
- Demand kW (per load): kW_d = (kW_rated × Qty × Utilization × Diversity) ÷ Efficiency
- Demand kVA (per load): kVA_d = kW_d ÷ PowerFactor
- Total demand: kW_total = Σ kW_d and kVA_total = Σ kVA_d
- Running current: I = (kVA_total × 1000) ÷ (√3 × V) for 3-phase, or I = (kVA_total × 1000) ÷ V for 1-phase.
- Starting demand: using StartMult to estimate motor inrush. Worst single start checks each load as it starts while others run.
- Recommended generator: apply safety and growth margins: kVA_reco = kVA × (1 + Safety% + Growth%)
These are planning equations. Always align with your project specifications and local electrical standards.
How to Use This Calculator
- Choose the supply phase and enter the site voltage.
- For each auxiliary load, enter rated kW and quantity.
- Set utilization for expected operating time intensity.
- Set diversity for probability of simultaneous use.
- Enter efficiency and power factor for realistic demand.
- Add hours/day to estimate daily energy consumption.
- Set start multipliers higher for motors and pumps.
- Press Calculate to view results above the form.
- Download CSV or PDF for reporting and sharing.
Built for fast site planning and clear documentation.