Are Bearings Making You Spin Your Wheels?

 The wheels of industry turn on bearings, so why do the wheels often vibrate, clatter, squeak, drag and overheat?

 Bearings can fail for lots of reasons. Most failures (as shown in Figure 1) are related to lubrication and contamination, but myths and misconceptions handed from one generation of maintenance engineers to the next help perpetuate many easily avoidable problems. These myths fall into three general areas of bearing use: installation, misapplication and lubrication.

Figure 1

Figure 1

Installation myth #1: It’s okay to hammer a bearing into position if needed – FALSE.

Never strike a direct blow to bearing. The rolling elements and raceway are hardened, but can still be damaged. A hammer blow can leave dents in the raceway that can cause noise and dramatically reduce bearing life. If installation is difficult, first check the shaft diameter, look for burrs, dirt or corrosion on the shaft. If needed, use a press to slide the bearing on. Apply pressure equally on the face of the inner ring to avoid damaging the raceways and rolling elements.

Installation myth #2: Off-the-shelf TGP shafting is the best option – FALSE.

It’s much more important to know the shaft’s tolerance range to be sure it meets your bearing manufacturer’s spec for diameter and roundness. Review the bearing manufacturer’s recommendations and measure/specify the correct shaft diameter.

Installation myth #3: It’s fine to hand-tighten setscrews one at a time – FALSE.

Setscrews should be tightened to the manufacturer’s recommend torque. Under tightening can allow the bearing to slip on the shaft. Over tightening can distort the raceway or crack the inner ring. Use the “half-full/full” rule for tightening setscrews – tighten the first setscrew to half the recommended torque, the second setscrew to the full torque, then go back to the first setscrew and apply full torque.

Application myth #1: Bearings should not be hot to the touch – FALSE.

Normal bearing operating temperatures can range from 80°F to 150°F, but certain applications may run higher or lower. Most bearings are rated for -20 to 220°F, but can be supplied with special grease, seals or heat stabilizing processes that allow them to operate at higher temperatures. Bearings normally run hotter at start up or right after re-lubrication because excess grease increases drag and friction in the bearing. Spikes up to 50°F are normal at start-up, and 30°F after re-lubrication. As the rolling elements purge excess grease through the seals, the bearings return to steady-state temperatures.

Application myth #2: Bigger bearings are always better – FALSE.

Bigger bearings with a higher load capacity may show a higher fatigue life, but if the load does not achieve the minimum requirement, the rolling elements can skid along the raceway instead of rolling. This can cause high temperatures, excessive wear, lubrication breakdown and bearing failure.

Application myth #3: Sealed/lubed-for-life bearings will last forever – FALSE.

Bearing life depends on grease life, which is affected by the operating conditions (speed and load) and environment (temperature and contamination). Grease life can be improved with enhanced seals, proper installation and proper grease selection. Ultimately, the best bearing is the properly lubricated bearing.

Lubrication myth #1: Re-lubrication once a year is sufficient – FALSE.

Start by reviewing the bearing manufacturer’s lubrication recommendations. These will give amounts and intervals as suggested starting points, but actual lubrication intervals may vary quite a bit, depending on load, speed, temperature, or environmental conditions. Applications with higher speeds, temperatures, or heavy contamination sometimes require frequent re-lubrication, possibly weekly or daily. By contrast, a mounted ball bearing in a lightly loaded, low-speed, clean environment may do fine with re-lubrication at 12 to 24 month intervals. Certain applications may need to be monitored and lubrication intervals/amounts adjusted accordingly.

Re-lubrication replenishes grease when the current grease breaks down or deteriorates because the base oil breaks down due to temperature. Without this, the lubricating property is gone and the result is metal-to-metal contact. Re-lubricating the bearing replenishes the oil, maintaining the proper film.

Pumping new grease into a bearing also helps flush away contamination. Many mounted bearings are designed to allow grease to enter the bearing cavity as close to the rolling elements as possible. As more grease is added, the old grease is pushed out of the seals (if the seals are purgeable). The purged grease carries out contaminants and keeps dirt away from the seals.

Lubrication myth #2: Always add grease until it purges from the seal – FALSE.

If you pump grease into the bearing until it purges out the seal, you probably have completely filled the bearing cavity. Excess grease can increase operating temperature and may create enough pressure to blow the seal out. However, in low-speed or dirty conditions where contamination may easily enter the seals, filling a bearing with grease may help improve performance. Application experience will dictate when the entire bearing cavity should be filled.

Lubrication myth #3: If a bearing makes noise, grease should be added – FALSE.

If a bearing is making noise, internal damage has likely occurred. This increases over time, with the potential for catastrophic failure. Adding grease may provide temporary relief, but a noisy bearing should be closely monitored and replaced at the first opportunity. The root of the failure should also be investigated either with independent or manufacturer failure analysis (manufacturer analysis requires removal of the bearing as soon as possible to aid in a more accurate diagnosis of the problem).

Lubrication myth #4: Any grease will do – FALSE.

Greases DO differ. Some may be incompatible because of the different thickeners (soaps) used. When two incompatible greases are mixed, they may thicken and harden or become thin and leak out of the bearing. For example, many electric motors use a polyurea thickener while some mounted ball bearings use lithium-complex thickeners. These greases are borderline compatible, and depending on the actual make up, may not work together. Grease types can also be incompatible based on the viscosity or type of oil in the grease, so consulting a lubrication supplier is always recommended.

Lubrication myth #5: Just shoot grease through the fitting – FALSE.

Always clean grease fittings and the grease gun tip. It’s good practice to put the grease gun tip in an oil bath or wrap it with a plastic cover to protect it.

Your plant’s uptime and OEE may “turn” on your bearings’ good health. If you are not achieving the desired operational life for some of them, a bearing manufacturer can assist you with proper selection and troubleshooting.

-Ian Rubin, Director of Marketing

Mobile Asset Management Coming to Browning HVAC App

Mobile asset management for HVAC components will soon be introduced in Browning’s widely used Toolbox Technician app! We are very excited to be demonstrating this new feature in booth 1021 at AHR Expo. Scheduled for availability in a Q2 update of Toolbox Technician, the new feature allows users to scan the 2D barcode or input the number on the Browning belt drive kit label and receive immediate access to product information. Registered users will be able to save the information to a personal library as a maintenance record, set push notifications for required system maintenance, and add related components, such as bearings, filters and compressors. The information will also be shareable with, and printable from, computers.

We surveyed contractors and building owners last year to find out how they are tracking assets and learned it’s a mix of paper notes, desktop data entry, or notes scrawled on the inside of access panels. Many admitted there were large gaps in their information because of the inconsistent way the data is captured, and there’s no centralized database or convenient way to set notifications for data they do have. Other asset management software requires tagging equipment first, but this asset management feature takes advantage of the Browning bar code kit labels provided to HVAC OEM’s for the last 10 years. Even if a drive kit label is unavailable, users can enter the kit number or other information into data fields in the app.

Asset tracking via the app will allow multiple users, such as building owners and contractors to access/share the information, eliminating the need to find paper notes or check rooftop units for logs stored there. The application updates are in beta testing, and the update is expected to be released in late spring of 2014.

The Toolbox Technician is an award winning mobile app for iOS or Android devices.  You can access all of Browning’s free mobile apps here or through iTunes or Android websites.

Introducing -60°F -250°F Temperature Rating for all Browning Raw-Edge, Notched V-Belts

We are very excited to introduce EPDM’s heat-resistance and durability advantages to all Browning raw-edge V-Belts, bringing an expanded temperature rating of -60° to 250°F to some of the most commonly used v-belt cross sections in the HVAC industry: AX, BX, CX, 3VX, 5VX and 8VX Gripnotch belts. The EPDM formulated belts have a 110-degree higher heat tolerance than industry-standard polychloroprene belts, making them ideal for rooftop blower units, commercial kitchens or industrial process exhaust systems.

These belts will set a new standard for the industry. Many technicians fail to account for the fact that a belt may reach 110-115°F while simply running in the sheaves at 72°F ambient temperature. If this heat is concentrated under a solid metal guard and the ambient temperature rises, it does not take long to approach the 140°F limit for common polychloroprene belts. On a rooftop in summer, even in northern climates, a v-belt drive can easily reach this critical temperature.

Browning’s EPDM formulation gives a 79% wider temperature window than polychloroprene belts.  We originally introduced a limited offering of EPDM belts and due to popularity expanded the offering to all notched belts, further developing the temperature range to 250°F. This heat rating will be valuable in all applications and industries, but particularly in warmer climates.

EPDM (ethylene propylene diene monomer) is a synthetic rubber compound formulated for superior strength, flexibility and resistance to heat, decay, ozone, oxidation and humidity. For more information visit Emerson Power Transmission.

Belt Dressing vs. Belt Slippage

Belt Dressing: Squealing V-Belts are commonly the result of belt slippage and are the audible indicator for service technicians that something in the drive needs to be corrected to maintain proper belt tension. Using a “Belt Dressing” is treating the symptom (noise) not the disease (slippage).

Belt dressings not only camouflage the disease, they can actually have an adverse effect. Many of these products are made from petroleum derivatives, which can cause degradation of the belt construction and belt swelling when the drive has prolonged or excessive exposure. In addition, these products can be highly flammable.

Belt Slippage: Belt slippage is commonly caused by improper belt tension, worn sheaves, alignment, drive contaminants such as grease or dirt or multi-groove drives having belts produced by varying manufacturers. To diagnose a squealing V-Belt, inspect sheaves for wear. The use of a Browning groove gauge will enable you to verify that sheaves have less than 1/32” wear. Wear greater than 1/32” results in the belt not maximizing torque transition, resulting in belt slippage.

This post originally appeared in THE NEWS’ Belt Drive Monthly.

We’re headed to AHR Expo!

It’s the time of year again. We are headed to AHR Expo in New York City January 21-23 at the Javits Center.  If you are planning to attend, we hope you’ll stop by to visit Emerson Industrial Automation in booth 1021!

This year in the booth we will introduce an expanded offering of Browning® EPDM v-belts, including new heat-resistance and durability advantages.  We will also be offering a sneak peek at our Asset Management mobile app feature, which helps contractors and building owners better track HVAC belt drives and related component assets.

There are also several exciting activities happening in the booth, including seminars and giveaways. Come for one or ALL of these events! Here’s the rundown:

  • Booth Seminars: Seminars highlighting HVAC OEM trends, tips for increasing belt drive and mounted bearing performance and techniques for realizing significant energy gains will occur in the booth at 11:15AM and 2:15PM daily.
  • 53” Tool Chest Giveaway: Stop by the booth to enter for a chance to win a 53” tool chest. Giveaway participants must be present at the “See the Green” event to win.
  • “See the Green” Event: We’ll be giving away our 53” tool chest in the booth during a #SeeTheGreen event at 1:30 PM on Wednesday, January 22nd.

We’re excited to see you all in the Big Apple. Don’t forget to look for Emerson Industrial Automation in booth 1021!

What is Belt Matching and Why is it Important?

When using a sheave with more than one groove, it is critical that the v-belts be the same length so they share the transmitted load. “Belt Matching” is a term used to define v-belts of equal length. If belts are not the same length and specification, the shortest belt carries the load as it tensions in the sheave first, and the remaining belts are simply going along for the ride. Length can vary widely among manufactures.

For example, a “non-matched” B38 wrapped v-belt has a published tolerance from The Rubber Manufacturers Association (RMA) of +0.7 0 – 0.7. or 45/64 of an inch (RMA engineering standard IP-20). This means each belt can vary as much as 1.4 inches and still be called a B38. Manufacturers make v-belts within RMA tolerances, but each makes them slightly different based on their manufacturing process. For this reason, a drive should never be installed with v-belts from different manufactures. The “matched” tolerance published by the RMA is significantly closer at 0.15 or only 1/64 of an inch variation.

The downside to not having a set of v-belts within matched RMA tolerance limits is:

  1. Belts cannot work together as a team and belts can fail prematurely
  2. Transmitting maximum HP is compromised
  3. V-belts and sheave grooves will wear unevenly
  4. Belt whip & vibration is increased

This post originally appeared in THE NEWS’ Belt Drive Monthly.

Welcome to Moving Conversations

Welcome to Moving Conversations, a blog by Emerson Industrial Automation’s Power Transmission Solutions business. We’re very excited to be blogging! We plan to use this space to discuss the latest automation and power generation technologies and services across all the industries we serve – HVACR, Turbomachinery, Food & Beverage and Metals, to name a few. We’ll also be talking about industry news and trends and sharing company news and industry event updates. As more content is shared here, it will be sorted by industry using the tabs at the top of the blog. So if you’re only interested in reading our “Food & Beverage” posts, not a problem! You will find all posts related to this industry under the “Food & Beverage” tab as the blog is populated. You will also be able to learn more about the authors contributing to Moving Conversations under the “Authors” tab. Thanks for stopping by! We hope you will be back for more great content from Emerson Power Transmission Solutions.

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Joe Corcoran

Joe Corcoran

Name: Joe Corcoran

Title: Manager, Global Service and Training

About:  Joe  is manager of High Performance Engineering for the Kop-Flex products.  The group he heads selects and designs couplings, and processes orders and inquiries for high performance couplings and torquemeters.