EOT Crane Brake Torque Calculator

Size brakes for Hoist, Cross Travel, and Long Travel motions.

1. Hoist Parameters

Ton

kg

mm

: 1

%

2. Motor & Safety

kW

RPM

kg·m²

Calculation Result

HOIST BRAKE

Load Torque: 0.0 Nm
Motor Torque: 0.0 Nm
Required Braking Torque
0.0 Nm
Safety Factor: --
Includes efficiency & safety margins

More Engineering Tools

Motor Power Girder Design Wheel Loads Wire Rope View All Calculators →

Understanding Brake Torque Calculation

Braking is one of the most critical safety aspects of an EOT crane. This calculator provides a preliminary holding-torque estimate for hoisting and a simplified deceleration-torque estimate for cross travel or long travel. It does not certify brake selection or stopping performance.

Hoist Brake Parameters

  • SWL & Hook Weight: The total static load that the brake must hold against gravity.
  • Drum Diameter & Gear Ratio: These mechanical parameters determine how the load force translates to torque at the high-speed motor shaft where the brake is typically mounted.
  • Rope Reeving (Falls): The number of rope falls (e.g., 4 falls) reduces the force on the drum, which directly reduces the required holding torque.
  • Safety Factor: Standard industrial practice requires a factor of 1.5 to 2.5. A factor of 2.0 means the brake can hold twice the maximum rated load.

Travel Brake Parameters (CT/LT)

  • Total Moving Mass: The combined weight of the crane bridge, trolley, and the maximum lifted load.
  • Deceleration Time: Unlike hoists, travel brakes are designed to absorb kinetic energy. A shorter stopping time requires a much higher braking torque.
  • Rolling Friction & Gradient: The calculator accounts for the natural resistance of the wheels and any slope in the gantry to ensure a controlled stop.

For crane mechanism engineers and quotation reviewers.

Engineering notes

How to interpret preliminary brake torque

Purpose: estimate motor-shaft holding torque for a hoist or simplified deceleration torque for CT/LT, then use the result to compare offered brake ratings and assumptions.

Inputs explained

Hoist load and drum
SWL, hook mass and drum diameter establish load torque.
Gear ratio, falls and efficiency
Convert drum-side load to the high-speed brake shaft.
Hoist safety factor
Multiplies calculated holding torque; the correct value must come from the governing design basis.
Travel mass, speed and stop time
Set the linear deceleration force for CT/LT.
Wheel, gearing, efficiency and gradient
Convert travel forces to shaft torque and show a simplified resistance estimate.

Formula basis

Hoist: load torque = mass x 9.81 x drum diameter / (2 x gear ratio x efficiency x falls)

required brake torque = load torque x selected safety factor

Travel: deceleration = (speed / 60) / stop time

deceleration torque = mass x deceleration x wheel radius / (gear ratio x efficiency)

displayed required torque = deceleration torque x 1.5. Gradient/rolling resistance is displayed separately and is not added to that final travel value.

Worked example

For a 10 t hoist plus 300 kg hook block, 400 mm drum, 30:1 gear ratio, 4 falls, 85% mechanical efficiency and 2.0 factor: calculated motor-shaft load torque is about 198.1 Nm and displayed required brake torque is about 396.2 Nm. A 15 kW, 1440 rpm motor has about 99.5 Nm rated running torque, but motor rated torque is not a substitute for the required holding-brake check.

Assumptions

  • Brake is located on the modeled high-speed shaft.
  • Load shares evenly between rope falls.
  • One mechanical-efficiency value covers the drivetrain.
  • Travel deceleration is linear and fixed factor is 1.5.

Results interpretation

  • Compare required torque with the brake's adjusted rated torque.
  • Verify mounting shaft and fail-safe spring-applied behavior.
  • Check stopping time and holding separately.
  • Review brake release voltage and control sequence.

Limitations

  • No thermal-energy or repeated-stop calculation.
  • No emergency-stop, overspeed or load-lowering transient model.
  • No brake wear, lining coefficient or ambient derating.
  • Travel result does not combine every resistance and slope case.

Related standards to check

Brake requirements depend on crane type, duty, jurisdiction and contractual design standard.

  • ISO 10972-1:2025 - general requirements for crane mechanisms and components.
  • ISO 8686-1:2012 - crane loads and load combinations.
  • Applicable crane product, electrical and local safety standards, plus the brake manufacturer's selection instructions.

FAQ

Can I select a brake from torque alone?

No. Thermal capacity, stopping duty, fail-safe action, release mechanism, environment and mounting must also be checked.

Why is motor torque shown?

It is a reference value from kW and rpm. It does not replace the load-holding calculation.

Should hoist and travel use the same method?

No. Hoist braking must hold a suspended load; travel braking primarily controls moving inertia and stopping behavior.

Next action: compare the complete brake data

Request adjusted rated torque, thermal rating, duty, lining/disc data, coil voltage, fail-safe action, manual release, enclosure, wear indication and stopping assumptions.

Related brake guideBrake buying guideBrake suppliers