Motor Sizing is a Pro feature
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Load Requirements
Typical: 1.0 (Precise duty), 1.15 (Normal), 1.25 (Heavy duty), 1.5 (Severe duty)
Environmental Factors
Motor Selection
Recommended Motor Size
15.0 kW
15.0 kW / 20.1 HP
Full Load Current
30.5 A
Starting Current (DOL)
198.0 A
Star-Delta Start
66.0 A
~2-2.5x FLA
Soft Starter
91.4 A
~3x FLA
Motor Efficiency
88.0%
Calculation Steps
1. Load power requirement: 10 kW
2. Load power normalized: 10.00 kW
3. Motor power (with service factor 1.15): 10.00 × 1.15 = 11.50 kW
4. Total derating factor: 1.000
5. Derated motor power: 11.50 / 1.000 = 11.50 kW
6. Recommended motor size: 15 kW (standard size)
7. Full Load Current (3-phase): I = P / (√3 × V × η × cosφ)
8. I = 15000 / (1.732 × 380 × 0.88 × 0.85) = 30.47 A
9. Starting Current (DOL): 30.47 × 6.5 = 198.04 A
10. Starting Current (Star-Delta): 198.04 / 3 = 66.01 A
11. Starting Current (Soft Starter): 30.47 × 3.0 = 91.40 A
Motor Sizing Guidelines
Service Factors:
- • 1.0: Precise duty cycle, no overload
- • 1.15: Normal duty, occasional overload
- • 1.25: Heavy duty, frequent overload
- • 1.5+: Severe duty, impact loads
Derating Required:
- • Temp >40°C: Derate 1% per °C
- • Altitude >1000m: Derate 3% per 500m
- • Poor ventilation: Derate 5-10%
- • Frequent starts: Increase size 25%
Starting Methods:
- • DOL: 6-8× FLC (simple, high inrush)
- • Star-Delta: 2-3× FLC (reduced torque)
- • Soft Starter: 3-4× FLC (smooth start)
- • VFD: 1.5× FLC (best control)