A motor and conveyor sizing calculator, built up over years of real use.

Enter a conveyor's VFD frequencies, motor, drive and load, and get speeds, torque, drive force and crop throughput — or work backwards from a target belt speed and throughput to a recommended gearbox ratio and motor size. Runs entirely in your browser, nothing to install.

Launch the Calculator Read the Story

THE STORY

Three lives of the same calculator

An Excel workbook

It started life years ago as MOTOR SPEED.xlsx — a spreadsheet for working out conveyor drive speeds, torque and motor sizing by hand, built up and refined over repeated real sizing jobs rather than designed in one sitting.

A SOLIDWORKS macro

The spreadsheet's logic was rebuilt as a standalone SOLIDWORKS VBA macro with its own form, so the same calculation could run inside the CAD environment — no more switching to Excel mid-design to check a motor size.

A browser app

The same engine — line-for-line, same constants, same defaults — is now a self-contained browser app: no build step, no install, works from any device. The macro still exists for use inside SOLIDWORKS; this is the version anyone can open.

Every version has produced the same numbers on the same inputs by design — the point was never to redesign the calculation, only to keep making it easier to reach.

HOW IT WORKS

Two directions, one engine

Both tabs share the same underlying physics — VFD frequency, motor slip, gearbox ratio, drive efficiency, star/delta connection — just run in opposite directions.

PERFORMANCE

Forward: what has this machine got?

Enter the actual machine — frequencies, motor, drive, belt/load, crop, incline — and get motor and drive speed, torque, star/delta drive force, conveyor speed, crop throughput and duty factors.

SIZING

Reverse: what machine do I need?

Enter the belt speed and throughput you want, and get the nearest standard gearbox ratio and next-standard IEC motor size for both star and delta running, checked back against what those standard picks actually deliver.

CALCULATIONS

Every formula, shown working

A reference tab documenting every constant and equation exactly as implemented — motor/drive speed, torque, force, conveyor geometry, crop load, incline, duty factor and the IE3 electrical estimate.

FEATURES

RESULTS

Live recalculation as you type, with the macro's original validation rules
Motor/drive RPM, torque, star & delta force, conveyor speed, throughput
Colour-coded payload and duty factors — green OK, amber marginal, red short
IE3 full-load current estimate for overload relay sizing, at your supply voltage

WORKFLOW

Plain-text report per tab, matching the macro's original report output
Copy to clipboard or download as .txt — no CAD required to generate it
Save / load inputs as JSON (Ctrl+S / Ctrl+O), including older single-tab files
Reset restores the active tab's defaults at any time

Electrical estimates use IE3 minimum efficiencies (IEC 60034-30-1, 50 Hz 4-pole) with typical power factors — useful for a first pass on overload sizing, not a substitute for checking the actual motor nameplate.

Try it yourself

Launch the calculator

Runs entirely in your browser — nothing to install, no CAD required. Opens directly from a link or straight off disk.

Launch the Calculator

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