⚙️ Electrical Calculators

⚡ Electrical Parameters, Formulas & Conversion Tricks (Maintenance Friendly)

🔹 1. Basic Power Conversions

• 1 kW = 1000 W
• 1 kW ≈ 1.34 HP
• 1 HP ≈ 0.746 kW
• 1 HP = 746 W

👉 Example:

• 5 HP motor = 5 × 0.746 = 3.73 kW
• 10 kW heater = 10 × 1.34 = 13.4 HP equivalent

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🔹 2. Motor Current Calculation (Approx.)

For Three Phase Motor:

I=P3×V×PF×ηI = \frac{P}{\sqrt{3} \times V \times PF \times \eta}I=3​×V×PF×ηP​

Where:

• P= Motor Power (W)
• V= Line Voltage (400–415 V India std)
• PF= Power Factor (0.8 typical)
• η= Efficiency (0.9 typical)

👉 Shortcut Trick (3-phase, 415V, PF=0.8, η=0.9): 1HP≈1.5Amp1 HP ≈ 1.5 Amp1HP≈1.5Amp

Example:

• 10 HP motor ≈ 15 Amp
• 20 HP motor ≈ 30 Amp

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For Single Phase Motor:

I=PV×PF×ηI = \frac{P}{V \times PF \times \eta}I=V×PF×ηP​

👉 Shortcut Trick (1-phase, 230V): 1HP≈5.5Amp1 HP ≈ 5.5 Amp1HP≈5.5Amp

Example:

• 2 HP motor ≈ 11 A
• 5 HP motor ≈ 27 A

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🔹 3. Useful Quick Conversions

• HP → kW: multiply by 0.746
• kW → HP: multiply by 1.34
• kW → Amp (3φ, 415V): I≈kW×10003×415×0.8×0.9I \approx \frac{kW \times 1000}{\sqrt{3} \times 415 \times 0.8 \times 0.9}I≈3​×415×0.8×0.9kW×1000​
• 👉 Shortcut: 1kW≈1.7A1 kW ≈ 1.7 A1kW≈1.7A
• Amp → kW: reverse formula

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🔹 4. Real Plant Tricks

1. Motor load checking without meter:
   • Thumb rule: 1 HP ≈ 1.5 A (3φ)
   • Agar 15 HP motor chal rahi hai aur nameplate load 23 A likha hai → but ammeter 30 A dikha raha hai → Motor overloaded hai.
2. Heater load test:
   • P (kW) = (V × I) / 1000
   • Agar 5 kW heater par 230V aur 22 A aa raha hai → 230×22/1000 = 5.06 kW, ok hai.
3. Cable size selection trick:
   • 1 mm² Cu wire ≈ 6–7 A safely
   • Example: 30 A load ke liye minimum 6 mm² cable chahiye.
4. Transformer load idea:
   • kVA = (√3 × V × I) / 1000
   • Example: 100 kVA transformer, 415 V → full load current = 100×1000/(√3×415) ≈ 139 A
5. Ampere without PF & Efficiency headache (fast estimation):
   • 1 HP (3φ, 415V) = 1.5 A
   • 1 kW (3φ, 415V) = 1.7 A
   • 1 kVA (3φ, 415V) = 1.4 A

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🔹 5. Conversion Cheat Table

Power	Formula / Shortcut	Example
HP → kW	HP × 0.746	10 HP = 7.46 kW
kW → HP	kW × 1.34	5 kW = 6.7 HP
kW → W	kW × 1000	2 kW = 2000 W
1 HP (3φ)	≈ 1.5 A at 415V	10 HP = 15 A
1 HP (1φ)	≈ 5.5 A at 230V	2 HP = 11 A
1 kW (3φ)	≈ 1.7 A at 415V	5 kW = 8.5 A
1 kVA (3φ)	≈ 1.4 A at 415V	50 kVA = 70 A

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🔹 6. “Tricks” Section

• “1 HP = 1.5 Amp Rule” (3-phase) – super fast motor current check
• “1 kW = 1.7 Amp Rule” – heater/load current estimate
• “1 mm² copper = 6 Amp Rule” – cable sizing shortcut
• “Transformer Full Load Current = kVA × 1.4” (for 415V)