How do I calculate brake torque from inertia and stopping time?

T = J × α, where J is total moment of inertia (kg·m²) and α = ω/t is angular deceleration (rad/s²). ω = 2π×n/60 (rad/s). So T = J × 2π × n / (60 × t_stop).

How do I calculate disc brake torque?

For a disc brake: T = F × μ × r × N, where F is clamping force (N), μ is friction coefficient (0.3-0.5 for dry, 0.1-0.2 for wet), r is effective radius (m), and N is number of friction surfaces (2 for caliper).

What is the braking energy?

Kinetic energy to be absorbed: E = ½Jω². In practical units: E = ½ × J × (2πn/60)². This energy is converted to heat in the brake. Important for thermal design.

How do I estimate moment of inertia?

For a solid cylinder: J = ½mr². For a hollow cylinder: J = ½m(r₁²+r₂²). For complex shapes, use CAD or the parallel axis theorem. For a conveyor, J = m×v²/ω² (where v is linear speed).

What safety factor should I use for brake sizing?

Typical safety factors: 1.5-2.0 for normal industrial brakes, 2.0-3.0 for safety-critical applications (hoists, cranes), 1.25-1.5 for holding brakes. Higher factors compensate for wear and environmental conditions.

Free Engineering Tool #097

Brake Torque Calculator

Calculate braking torque from inertia and deceleration (T = J × α) or disc brake force (T = F × μ × r). Includes braking energy and average power dissipation.

T = J×αT = F×μ×rBraking Energy

Results

Required Brake Torque (with SF)

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Nominal Brake Torque

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Angular Deceleration α

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Braking Energy

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Average Braking Power

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Braking Torque from Inertia

Disc Brake Torque

Braking Energy

Example — Conveyor Brake

Given: J = 2.5 kg·m², n = 1500 RPM, t_stop = 3 s, SF = 1.5

ω = 2π×1500/60 = 157.1 rad/s

α = 157.1/3 = 52.4 rad/s²

T = 2.5 × 52.4 = 130.9 N·m

T_design = 1.5 × 130.9 = 196.3 N·m

E = ½ × 2.5 × 157.1² = 30,870 J ≈ 30.9 kJ

Brake Torque Calculator | T = J×α | Free Online Tool

Published by admin on February 15, 2026 February 15, 2026

Results

Braking Torque from Inertia

Disc Brake Torque

Braking Energy