5 HP motor kitna ampere kheencheta hai?

5 HP 3-phase motor at 415 V roughly 6.9 A draws at full load (assuming PF 0.85, η 0.88). Starting time mein 6× yaani ~41 A ka spike aata hai — isliye MCB 'D-curve' type use karein, normal 'C-curve' trip ho jaayega.

What is the difference between FLA and starting current?

FLA (Full Load Amperes) is the steady-state current a motor draws running at rated output. Starting current is the surge when the motor first energises — typically 6–8× FLA for Direct-On-Line (DOL) start, lasting 1–5 seconds. Size cables for FLA; size contactors and MCBs for starting surge.

Power factor aur efficiency kya hai?

Power factor (PF) = ratio of real power to apparent power — typically 0.85 for standard induction motors. Efficiency (η) = how much electrical input becomes mechanical output — 0.85–0.92 for modern motors. Dono milke motor ka current draw decide karte hain.

What size MCB for a 5 HP motor?

5 HP draws ~7 A FLA. MCB: pick 10 A D-curve (motor-duty). D-curve tolerates 10–14× overcurrent for starting surge without tripping. For larger motors, switch to MCCB with adjustable thermal-magnetic settings.

Where can I get a clamp meter to measure motor current in Noida?

Shri Narayan Machinery at Sector 9, Noida stocks Fluke clamp meters (317, 319, 323, 324 models) — True RMS, inrush current, min-max capture. Essential for verifying motor FLA and starting current in the field. Call +91-9811104037.

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Motor Full-Load Current (FLA) Calculator

Calculate FLA from kW / HP, voltage, phase, power factor

kW या HP से Full Load Amperes (FLA) calculate करें

Quick Overview

Motor Full-Load Amperes (FLA) is the current drawn by a motor running at its rated mechanical output power. The formula is I = (P × 1000) / (√3 × V × PF × η) for three-phase motors, or I = (P × 1000) / (V × PF × η) for single-phase, where P is motor power in kW, V is line voltage, PF is power factor (typically 0.85 for standard induction motors), and η is efficiency (typically 0.88 for Indian IE2-class motors). A 5 HP (3.73 kW) 3-phase motor at 415 V draws 3730 / (1.732 × 415 × 0.85 × 0.88) = 6.9 A. Starting current is typically 6–8× FLA for direct-on-line start (DOL) or 2–3× with star-delta or soft starter. Use FLA when sizing cables, MCB / MCCB ratings, and overload relays; use starting current when selecting contactor rating and short-circuit protection. This calculator handles both 1-phase and 3-phase Indian standard motors.

Calculator

Motor power(मोटर पावर)

Power unit(यूनिट)

Voltage(वोल्टेज)

Phase(फेज़)

Power factor (PF)(Power factor)

Standard IE2: 0.85 · IE3: 0.88 · VFD: 0.92

Efficiency (η)(efficiency)

Standard IE2: 0.88 · IE3: 0.92

Starter type(Starter)

FLA (running)

6.9A

Start current (6×)

42A

Also in kW

3.73kW

Formula: I = (kW × 1000) / (√3 × V × PF × η) = (3.73 × 1000) / (1.732 × 415 × 0.85 × 0.88) = 6.9 A. Size cable + MCB for FLA; size contactor for start current (Direct-On-Line (DOL)).

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ƒFormula

3-phase: I = (kW × 1000) / (√3 × V × PF × η) | 1-phase: I = (kW × 1000) / (V × PF × η)

I = FLA in amperes. kW = motor power (multiply HP by 0.746 to convert). V = line voltage. PF = power factor (typically 0.85 for standard IE2 motors; 0.88 for IE3; 0.92 for high-efficiency / VFD-driven). η = efficiency (typically 0.85–0.92 depending on class). Starting current ≈ 6× FLA for DOL; 2× for star-delta; 1.5× for VFD.

Units: Current: ampere (A) · Power: kilowatt (kW) · Voltage: volt (V)

Motor ka FLA (Full Load Current) kaise calculate karein?

Motor Full Load Amperes (FLA) matlab motor apni rated power pe kitna current pull karta hai. Formula 3-phase ke liye: I = (kW × 1000) / (√3 × V × PF × η). Single-phase: I = (kW × 1000) / (V × PF × η). Typical values: PF = 0.85, efficiency η = 0.88 for standard Indian induction motors. HP ko kW mein convert karne ka formula: 1 HP = 0.746 kW. Starting current hamesha 6-8× FLA hoti hai DOL starter pe — isliye contactor aur MCB ki rating FLA se nahi, starting current se karna hota hai.

उदाहरण / Example: Example: 7.5 HP (5.59 kW) 3-phase motor at 415 V. FLA = 5590 / (1.732 × 415 × 0.85 × 0.88) = 10.3 A. Starting current (DOL) ≈ 70 A. Cable size 2.5 sq.mm (handles 20A running), MCB 16A with motor-duty (D-curve), contactor rated ≥ 25A.

Worked Examples

Sizing a 5 HP motor circuit

Problem: 5 HP 3-phase motor at 415 V — what is FLA and starting current?

Solution: kW = 5 × 0.746 = 3.73. FLA = 3730 / (1.732 × 415 × 0.85 × 0.88) = 6.9 A. DOL starting current ≈ 6.9 × 6 = 41 A. Cable 1.5 sq.mm copper (14 A ampacity). MCB 10 A D-curve (motor-duty). Contactor rated ≥ 16 A.

Converting HP to amps for a 1-phase pump

Problem: 2 HP single-phase water pump at 230 V.

Solution: kW = 1.49. FLA = 1490 / (230 × 0.85 × 0.88) = 8.6 A. Single-phase pumps often have lower PF (~0.75) — recalculate: 1490 / (230 × 0.75 × 0.85) = 10.2 A. Use 1.5 sq.mm cable, 16 A MCB.

High-efficiency IE3 vs standard IE2

Problem: 10 kW motor — why does IE3 draw less current than IE2?

Solution: IE2: PF 0.85, η 0.88 → FLA = 10000 / (1.732 × 415 × 0.85 × 0.88) = 18.6 A. IE3: PF 0.88, η 0.92 → FLA = 10000 / (1.732 × 415 × 0.88 × 0.92) = 17.1 A — 8% less current for the same mechanical output. Over a motor's life (20,000+ hours), IE3 saves significant electricity cost.

Standard Induction Motor FLA at 415 V 3-Phase, 230 V 1-Phase (approximate)

HP	kW	FLA @ 415V 3-φ	FLA @ 230V 1-φ	DOL Start Current (A)
0.5	0.37	0.8	2.6	4.8 (3ph) / 16 (1ph)
1	0.75	1.5	5.0	9 / 30
2	1.49	2.9	10	17 / 60
3	2.24	4.2	14	25 / 84
5	3.73	6.9	22	41 / 132
7.5	5.59	10.3	32	62 / 192
10	7.46	13.5	—	81 / —
15	11.2	20	—	120 / —
20	14.9	27	—	162 / —
25	18.7	33	—	198 / —
30	22.4	40	—	240 / —
50	37.3	66	—	396 / —

Values assume PF = 0.85, efficiency = 0.88 (typical IE2 class). Starting current shown for DOL start; divide by 3 for star-delta; divide by 6 for VFD soft-start. Single-phase not available above 7.5 HP in Indian markets.

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Frequently Asked Questions — Motor Full-Load Current (FLA) Calculator

I = (HP × 0.746 × 1000) / (√3 × V × PF × η). For a standard 415 V 3-phase IE2 motor: I ≈ HP × 1.4. A 5 HP motor draws roughly 7 A; 10 HP draws roughly 14 A. For exact value use our calculator with your specific PF and η.

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