Designing a conveyor system involves more than just bolting a motor to a frame. If you undersize the motor, it won't start under load due to breakaway torque . If you oversize it, you waste thousands on electricity and oversized VFDs. In this guide, we will walk through the engineering math required to size a conveyor motor and gearbox correctly, specifically focusing on the critical "Dynamic Tension" resulting from inertia. Table of Contents 1. The Physics: Effective Pull (Te) 2. Calculating Motor Power (Worked Example) 3. The Inertia Problem: VFD vs DOL 4. Gearbox Ratio Selection 5. Frequently Asked Questions Advertisement 1. The Physics: Effective Pull (Te) The first step in any sizing calculation is determining the Effective Pull ( T e ) . This is the sum of all forces resisting the motion of the belt. The Basic Formula: T e = F friction + F gravity + F material...
Putting Theory into Practice We have covered the theory of Buckling (Part 1) , the Slenderness Ratio (Part 2) , and the critical decision between the Euler and J.B. Johnson formulas (Part 5) . Now, let’s solve a real-world design problem. We will perform the calculation manually first to understand the physics, and then look at how to automate this in Excel. Search for Roark's Formulas for Stress and Strain Advertisement The Design Problem Scenario: A machine designer needs to calculate the allowable load for a rectangular steel column. Material: AISI 1040 Hot-Rolled Steel Dimensions: 80 mm × 30 mm cross-section, 380 mm length. End Conditions: The upper end is pinned; the lower end is welded securely into a socket (Fixed). Figure 1: Our design example: A 380mm long rectangular column with Pinned-Fixed ends. Note that it will buckle along its weakest (30 mm) dimension. Step 1: Geometric Properties First, we ana...