Calculator Input Form
Example Data Table
| Example | Type | Voltage (V) | Current (A) | PF | Efficiency (%) | Load (%) | Monthly Energy (kWh) | Monthly Cost |
|---|---|---|---|---|---|---|---|---|
| Workshop fan motor | Three-phase | 400 | 18.00 | 0.88 | 92.00 | 80.00 | 1,826.12 | 255.66 |
| Single-phase compressor | Single-phase | 230 | 12.00 | 0.82 | 85.00 | 75.00 | 244.43 | 44.00 |
| Process pump motor | Three-phase | 415 | 32.00 | 0.91 | 94.00 | 90.00 | 5,651.50 | 678.18 |
Formula Used
1) Apparent power
Single-phase: kVA = (V × I) ÷ 1000
Three-phase: kVA = (√3 × V × I) ÷ 1000
2) Reference input power
Reference input kW = Apparent power (kVA) × Power factor
3) Estimated operating input
Estimated input kW = Reference input kW × (Load factor ÷ 100)
4) Estimated shaft output and loss
Shaft output kW = Estimated input kW × (Efficiency ÷ 100)
Loss kW = Estimated input kW − Shaft output kW
5) Energy and cost
Daily energy = Estimated input kW × Hours per day
Monthly energy = Daily energy × Days per month
Operating cost = Energy consumption × Tariff
How to Use This Calculator
Step 1: Choose single-phase or three-phase motor operation.
Step 2: Enter voltage, reference current, power factor, efficiency, and average operating load.
Step 3: Add runtime, tariff, and optional emissions, rating, and service factor values.
Step 4: Submit the form to view input power, output power, losses, energy, cost, and utilization results.
Step 5: Use the chart and export buttons to compare values and download the result summary.
Frequently Asked Questions
1. What does this calculator estimate?
It estimates apparent demand, electrical input, shaft output, energy consumption, operating cost, efficiency losses, emissions, and utilization against rated motor output.
2. Why is load factor included?
Many motors do not run at full load all day. Load factor scales the reference electrical input to a more realistic operating demand.
3. Should I enter measured current or nameplate current?
This page works best when you enter full-load or reference current, then use load factor to estimate average operation. Measured current can also be used if load factor is adjusted carefully.
4. What is the difference between input power and shaft output?
Input power is electrical power drawn from the supply. Shaft output is the useful mechanical power after efficiency losses inside the motor.
5. Why can cost change sharply with small input changes?
Motors often run many hours per month. Small power changes multiply across long runtime, raising both energy use and operating cost noticeably.
6. What does the service limit status flag mean?
It compares estimated shaft output with rated output multiplied by service factor. Exceeding that level suggests overload risk or unrealistic assumptions.
7. Can I use this for energy audits?
Yes. It is useful for screening motor demand, comparing operating scenarios, and identifying high-cost equipment before deeper field measurements or audits.
8. Does this replace detailed motor testing?
No. It is a planning and estimation tool. For final engineering decisions, confirm values with measurements, manufacturer data, and site operating conditions.