Electric motor on a factory floor at dusk

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CritSpeed

The speed nobody talks about
until the machine talks.

Critical speed, natural frequency, and a safe operating range for rotating machinery — on the phone. Thomson’s web calc needs a browser. COMSOL needs a license. This needs a number and a pocket.

Critical speed
Safe range
Works offline

Get the app when stores go live →

Store listings are not public yet. This link stays valid the hour they go live.

See how it works

01 — The problem

The useful number is usually on a desktop you are not standing next to.

Web calculators for screw critical speed. FEA for a full rotor. Spreadsheets named final_v7. None of that is in your pocket when the motor is in front of you.

CritSpeed is the field calculator: resonance, natural frequency, safe operating range. Offline. Not a replacement for a rotordynamics study.

Engineer holding a phone next to a plant-floor motor

02 — The job

One job. Stay off the peak.

A number you can check before the machine tells you.

Critical speed

The RPM where resonance wants to live.

Natural frequency

The other way of saying the same warning.

Safe operating range

Where you can run without sitting on the peak.

Electric motors first

Built for rotating machinery you actually stand next to.

Works offline

Plant wifi is not a given.

No ads. No account.

A calculator. Not a lead form.

03 — On the device

A pocket calculator. Not a fake Campbell diagram.

Real in-app screens go here when we have captures. We will not invent FEA UI. The product is motor critical speed, on the device.

04 — Proof

On deviceNo desktop seat required

NoneAccount to calculate

NoneAds

05 — Privacy

Shaft numbers stay on the phone

Geometry and RPM are not uploaded to an engineering SaaS.

No cloud — No account.
No tracking — No ad ID on a motor tag.
Fully offline — Works without internet after install.
You own the data — Delete it on the device.

CritSpeed is an engineering aid. It is not a substitute for a rotordynamics analysis, OEM limits, or a qualified engineer. Verify against the machine you are running.

06 — Price

One price. Full app. No ads.

Subscription only. No free tier. No trial. Cancel in your store account.

Plant pass

$0.99/mo

$9.99/yr

Included: critical speed · natural frequency · safe range · offline · no ads

07 — FAQ

Questions search engines actually ask

Is this COMSOL on a phone?

No. It is a field calculator, not a finite-element seat.

Does it work offline?

Yes.

Do I need an account?

No.

Are there ads?

No.

What does it cost?

$0.99 per month or $9.99 per year. Subscription only. No free trial.

Is it only for electric motors?

Motors are the point. Use it as a first check on rotating machinery — then confirm properly.

iPhone or Android?

Both, when listed. This page and the QR stay the same.

Check the speed. Then run the machine.

CritSpeed is the critical-speed calculator that fits in a pocket, not a workstation.

Get the app when stores go live →

Store listings are not public yet. This link stays valid the hour they go live.

Sending this to a friend? One QR. The phone opens the right store when it exists — or this page until then.