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Three-Phase Motor Sizing Calculator — Free Online Tool

kW + V + cos φ + efficiency → current + protection

Three-phase motor sizing: rated current from kW, voltage, power factor, efficiency. Plus locked-rotor amps + recommended overload protection.

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Three-Phase Motor Sizing Calculator

Full-load current, locked-rotor amps, recommended overload protection. From kW + voltage + power factor + efficiency. IEC standard sizing.

How to use this tool

  1. 1

    Motor rating

    kW + voltage + cos φ + efficiency.

  2. 2

    See full-load current

    Plus locked-rotor amps.

  3. 3

    Protection sizing

    Overload + short-circuit recommendations.

Frequently Asked Questions

Three-phase current formula?
I = P / (√3 × V × cos φ × η). Power in W, voltage line-to-line, cos φ = power factor, η = efficiency. For 11 kW @ 400V, 0.85 PF, 92% eff: I = 11000 / (1.732 × 400 × 0.85 × 0.92) ≈ 20.3 A.
Locked-rotor (starting) current?
Typically 5-7× full-load current. Code letter on nameplate: B = 6.3-7.1 kVA/HP, F = 5.0-5.6, etc. Affects upstream protection + cable sizing.
Overload protection setting?
Per IEC: 1.05-1.20 × full-load current (FLA). For class 10A relay (most common): 1.15 × FLA. Set higher for high-inertia loads (compressor, fan with damper).

Key Takeaways

  • Three-Phase Motor Sizing Calculator is a free, browser-based calculator tool — kw + v + cos φ + efficiency → current + protection.
  • No signup, no downloads, no file uploads — your data stays on your device.
  • Works on desktop, tablet, and mobile. Install as a PWA for offline access.

How to Use Three-Phase Motor Sizing Calculator

  1. Open the tool: Launch Three-Phase Motor Sizing Calculator on Toololis — no account or download needed.
  2. Enter your data: Paste text, enter values, or select a file directly in your browser.
  3. Get instant results: Everything is processed locally — results appear immediately.
  4. Copy or download: Save your output or share it. Bookmark for quick access next time.

Three-Phase Motor Sizing Calculator — Quick Facts

Price
Free — no limits, no watermarks, no paywalls
Privacy
100% browser-based — no data is sent to any server
Platform
Any modern browser on desktop, tablet, or mobile
Category
Calculator Tools on Toololis
Offline
Works offline after first visit (Progressive Web App)
FeatureDetails
ToolThree-Phase Motor Sizing Calculator
CategoryCalculator
Signup RequiredNo
File UploadNone — processed in browser
Mobile SupportFully responsive
CostFree forever

Why Use Three-Phase Motor Sizing Calculator?

You should try Three-Phase Motor Sizing Calculator for a quick, private way to kw + v + cos φ + efficiency → current + protection. All processing happens in your browser. Your files and data never leave your device. According to web.dev, client-side processing is the gold standard for privacy.

On the other hand, dedicated APIs or desktop tools suit batch processing better. They also handle server-side automation. For everyday tasks, browser tools offer the best speed, privacy, and convenience.

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100% Privacy. This tool runs entirely in your browser. Your data is never uploaded to any server.