Bearings on belt-driven machinery are highly susceptible to damage and premature failure due to incorrect belt tension. Maintaining the correct belt tension is essential to ensure optimal performance and extend the lifespan of your equipment. Failure to do so can lead to increased maintenance costs, unexpected downtime, and serious mechanical failures.

In this article, we will look at how improper belt tension can strain and damage your equipment, how to use a belt tensioner gauge, and how to adjust belt tension with a belt tensioning tool.

Why Improper Belt Tension is Detrimental

Improper belt tension, whether too tight or loose, can quickly damage equipment. When belts do not have proper tension, they can cause excessive wear on pulleys, bearings, and motors. This damage can happen anytime, wasting dozens of man-hours and halting productivity. Being forced to prematurely replace belts, pulleys, and even shafts or motors can disrupt your maintenance schedule and lead to costly repairs.

Regular inspections and adjustments help prevent these issues and ensure your machinery runs smoothly and efficiently.

What Happens If the Belt Is Too Tight?

An overly tight belt creates excessive strain on the shaft, potentially pulling it out of alignment. The shaft may pull to one side, making it off-center. This misalignment places additional stress on the bearings, causing premature failure. The increased friction also accelerates wear on the belt itself, leading to cracking, fraying, or complete breakage.

Additionally, excessive tension can:

• Generate high radial loads, damaging the bearing housing and supporting structure.
• Cause over-amperage in the motor due to increased resistance, leading to overheating and possible motor failure.
• Warp or bend shafts, further misaligning components and affecting overall machine performance.

What Happens If the Belt Is Too Loose?

A belt that is too loose can slip on the pulley, reducing the efficiency of power transmission. Belt slippage occurs when the belt and the pulley do not have a firm grip. This, in turn, reduces the power transfer from your motor, decreasing efficiency and wasting energy. The friction from these slips can generate massive amounts of heat, damaging the belts and the machine or even starting a fire.

Common consequences of a loose belt include:

• Belt slippage, which decreases efficiency and increases energy consumption.
• Overheating, caused by excessive friction when the belt fails to properly engage with the pulley.
• Premature failure of the belt and related components due to inconsistent performance and excessive vibrations.

A loose belt can also lead to premature failure of the belt itself, as well as the bearings. For this reason, it’s important to watch out for common signs of a loose belt to avoid belt slippage and misalignment. These signs can include:

• Cracked or fraying belt edges
• Squealing or chirping noises during start-up
• Belt hardening or glazing
• Over-amperage in the motor
• Premature wear on pulleys and bearings

Maintaining proper belt tensions with regular inspections and maintenance is imperative to prevent these problems.

Signs Your Bearings May Be Damaged

Bearings are critical components that allow smooth rotation of shafts and other moving parts. If a bearing becomes damaged, it can lead to severe machine malfunctions. While normal wear and tear are inevitable, improper belt tension accelerates the process, leading to premature failure.

Common signs of bearing failure include:

• Vibration: If the raceway is damaged by abrasion, the balls or rollers will bounce around the raceway, increasing vibration levels. All machines vibrate during operation. However, as bearings wear down and begin to fail, the volume of vibration rises significantly from the baseline vibrations. 
• Excessive Noise: If your bearing is suddenly extra noisy during operation, it has likely degraded and needs to be replaced. This excess noise comes from the rollers or balls bouncing around or rattling along the raceway. 
• Hot Operating Temperature: Bearings heat up during operation, but if the raceways are damaged (or unlubricated), the bearing will experience excessive friction heat. While a machine may experience temperature increases when first starting up or after a greasing, anything unusual should be investigated as soon as possible. 

Maintenance technicians should record operating vibration, noise, and temperature to establish baseline operating condition data. Maintenance routines should compare new data to baseline data and watch for anomalies in these categories.

If you notice excessive vibration, noise, or temperature in operation, the bearing has almost certainly failed and will require immediate replacement to avoid catastrophic equipment failure.

Methods for Belt Tension Measurement and Alignment

Measuring and aligning a belt correctly is the best way to avoid an over-tightened or loose belt. In order to do so, you’ll need to know the different methods of how to measure belt tension.

1. Force Deflection Belt Tension Method

V-belts can be tensioned with a force deflection method or a frequency meter. Analog tension gauge results can then be compared to a V-belt tensioning table to determine the level of tension.

A pencil gauge tool is inexpensive and reliable but can be rather time-consuming. It requires a lot of measurements and calculations. Generally, our customers prefer using analog tension gauges instead due to their accuracy and relatively low cost.

2. Belt Frequency Meter V-Belt Tension Method

IBT’s preferred belt tension measurement method is using a belt frequency meter because of its precision and time efficiency. Its incredible accuracy will ensure your machinery is measured at the exact specifications required, allowing for belt longevity.

While a belt frequency meter is more expensive, the high initial cost is typically offset by the labor hours saved by manually calculating belt tension with analog gauges.

3. Belt Sheave Alignment Tool

Alignment can also significantly affect bearing wear and tear. A sheave alignment tool is the best way to ensure your belt is properly aligned. Many of these tools use lasers to project and receive information and show alignment. By aligning the lasers, you can achieve perfect alignment.

Need Help with Industrial Belt Alignment and Tension?

IBT’s Facility Maintenance Services Division is here to help align and tension belts up to the correct standards. Our professionals can identify the root cause of belt and bearing issues, ensuring your equipment is at its most optimal performance level.

We offer the following services:

• 24/7/365 Troubleshooting and Repair Service
• Vibration Analysis
• Dynamic Balancing
• Precision Laser Alignment
• Bearing, Coupling, Sheave Installation
• Predictive and Preventive Maintenance
• Equipment Inspection and Performance Analysis
• Failure Analysis
• Component Repair and Overhaul
• Mechanical Upgrade and or Reconfiguration
• Facility Maintenance Assessment
• Infrared Thermography

Proper belt tensioning is not just about preventing wear and tear—it’s about ensuring the efficiency, safety, and longevity of your machinery. If you suspect your belts, bearings, or pulleys are under undue stress, contact us today for expert maintenance and support.