Conveyor Belt Basics 101

Conveyor Belt Components

Conveyor belts are generally composed of three main components:

  • Carcass
  • Skims
  • Covers




    • The rubber, PVC or urethane between plies
    • Important contributor to internal belt adhesions, impact resistance, and play a significant role in determining belt “load support” and “troughability”
    • Improper or marginal skims lead to ply separation and or idler junction failure


      The reinforcement usually found on the inside of a conveyor belt is normally referred to as the carcass. In a sense, the carcass is the conveyor belt since it must:

      • Provide the tensile strength
      • Absorb the impact of the impinging material being loaded onto the conveyor belt
      • Provide the bulk and lateral stiffness required for the load support
      • Provide adequate strength for proper splice holding



      Used in belt construction to protect the carcass and if possible extend service life. Covers do provide the finished belt with a wide variety of desirable properties including:


      • Texture
      • Cleanability
      • Chemical Resistant

      NIBA Belt Tracking Video

      00:00 Introduction
      01:40 General Mechanics
      07:00 Lightweight Belts
      09:26 Heavyweight Belts

      diagram of conveyor belt

      General Conveyor Problems


      • Excessive Cover Wear /Carcass Failure
      • Splice Failure
      • Slippage at drive
      • Tracking

      Drive Changes / Changes in Load


      • Increased drive HP
      • Reducer/V-Belt Drive Change
      • Increase in tonnage handled
      • Change in weight or consistency of material being conveyed
      • Change in starting system
      • Major changes in ambient temperature
      • Frozen Idlers

      Corrective Action

      • Replacement of failed components
      • Lubrication
      • Clean up or house keeping
      • Record action taken to gauge progress

      General Tracking / Training Procedures


      • Tracking is the process of adjusting idlers, pulleys and loading conditions in a manner that corrects off running
      • Tracking should begin on the return side near the head pulley and move toward the tail
      • Track the belt empty at first and then loaded
      • Make adjustments preceding the region of trouble
      • Permit the conveyor to make several revolutions
      • If over correction has occurred, move back the same idler
      • If the belt runs to one side at a particular point on the conveyor, the cause is probably an alignment problem preceding the trouble area


      Q: What is proper minimum belt tension on a conveyor belt?

      A: Proper minimum belt tension is the required tension necessary for the belt conveyor (or belt elevator system) to operate properly for its intended application and in its current environment.

          • Minimum belt tension is great enough so that the belt conforms to the crown on any crowned pulley.
          • Minimum belt tension is great enough so that the belt does not slip in relation to the drive pulley’s standard conditions, as well as demands.

      Q: What are the top conveyor belt tracking problems?

      A: There are eight common conveyor belt tracking problems to be aware of.

          • Belt Camber
          • Skew (Bow)
          • Too low belt tension
          • Failure to properly square belt ends
          • Poor installation of mechanical fasteners
          • Improperly executed belt splice or vulcanization
          • Structural defect or maladjustment in the conveyance system
          • Material Build-up

      Tension Calculations Using The Full Motor Method

      chart with formulas to calculate tension using full motor method


      Chart with specs for conveyor belts