Motor Kilowatt-hour (kWh) Calculator
Estimate energy consumption and cost for electric motors
Motor kWh Calculator
For single and three-phase motors
Results:
kWh per Day: 0.00
kWh per Month: 0.00
kWh per Year: 0.00
Cost per Day ($): 0.00
Cost per Month ($): 0.00
Cost per Year ($): 0.00
How to Use the Calculator
Motor Power
- Enter the motor's rated power.
- Select the unit: Kilowatts (kW) or Horsepower (HP).
Efficiency & Hours
- Input the motor's operational efficiency in percentage (e.g., 85 for 85%).
- Enter the average daily operating hours (0-24).
Days & Cost
- Specify the number of operating days per year (0-365).
- Enter your local electricity cost per kilowatt-hour ($/kWh).
Motor Energy Consumption Fundamentals
Motor Power & Efficiency
Motor power (kW or HP) is the output mechanical power. To find the electrical input power, motor efficiency must be considered. Efficiency is the ratio of output power to input power.
kWh & Cost
- Kilowatt-hour (kWh) is a unit of energy, representing one kilowatt of power consumed for one hour.
- Electricity cost is typically billed per kWh.
Key Concepts:
Input Power (kW) = Output Power (kW) / Efficiency (%)
Energy (kWh) = Power (kW) × Time (hours)
Calculation Formulas
Motor Power (kW_input) = Motor Power (kW) / (Efficiency / 100)
kWh per Day = kW_input × Operating Hours
kWh per Month = kWh per Day × 30.44
kWh per Year = kWh per Day × Operating Days
Cost = kWh × Cost per kWh
Example Calculation
Motor Details:
Motor Power: 10 HP
Efficiency: 90%
Operating Hours: 12 hours/day
Operating Days: 300 days/year
Cost per kWh: $0.15
10 HP = 7.457 kW
Input kW = 7.457 kW / (90 / 100) = 8.285 kW
kWh per Day = 8.285 kW × 12 hours = 99.42 kWh
kWh per Year = 99.42 kWh/day × 300 days = 29826 kWh
Cost per Year = 29826 kWh × $0.15/kWh = $4473.90
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