2 WHAT WE WILL COVER: Belt Drives on HVAC Equipment: Advantages, Terms, Belt Construction, Belt Length Variation, Replacement & Equipment Dynamics,Proper Drive Maintenance:Importance, Safety, Belt Tension, Worn Sheave, Increasing Drive LifeEnergy Savings Opportunities:Upgrade Belt, Sheave Wear & Proper TensionEnergy Savings Opportunities Part II:Retrofitting old worn out drivesSustaining Drive Efficiency:Self- Tensioning Motor Bases & Automatic Bearing LubricatorsSummary:Tools & Available ResourcesQuestions? & Contact Information
4 Equipment Dynamics OEM trends for smaller center distances. This puts much greater but demands more for the entire driveShorter Center Distances – Increased Belt CyclesLighter Structural Framework – Harder to maintainproper alignment & drive tension. Drive is twisted causing issues.Higher Speeds – Need for better system balance to prevent vibration & noise issues.Traditional CenterDistance Requirement(20-28 inches)New Center DistanceTrend(12-18 inches)
5 Advantages of using V-Belt drives Economical -Low initial cost and low cost to maintainQuiet - Smooth, quiet operationClean- No lubrication is requiredEasy to install & maintain – Belts wear graduallyForgiving - Withstand installation/maintenance abuse & still give good drive lifeEfficient – Drive performance between % when maintained & installed correctlyAvailability – Replacements can be purchased everywhereVersatile – cover a wide range of horsepower's & speedsRugged – Last for long periods of time Shock Absorbing5
6 Key Terms and Definitions Center Distance - Amount of distance between driver and driven shaftsService Factor - Required Horsepower x Service Factor= Design HorsepowerDatum Diameter – The Datum Diameter as the effective diameter for determine the pitch length of the belt for center distance calculation. Listed for A, B, C & D Sheaves. Adopted in 1987 by RMA/MPTA.Pitch Diameter – The diameter where the belt cords are placed in a belt.Torque - A twisting or turning forceAs speed decreases, torque increasesRatio – Driver divided by Driven
7 Belt construction What they do: Cogged Belts: Wrapped BeltWhat they do:Transmit torque & HorsepowerHeat and Oil ResistantStatic ConductingLow VibrationLow MaintenanceGood for Shock LoadsFabricPolyester cordsNeoprene RubberCogged (Raw-Edge)BeltCogged Belts:Transmit more horsepowerRun cooler; Ave 16º to 30ºTemperature Range -60º to +250ºSlightly louderNeed closer alignmentFabricPolyester cordsEPDM
8 Belt Length Variation RMA* Standard Standard Datum Lengths Permissible Matching Matching MatchingLength Cross Section Deviation from Limits for Limits for Limits forDesignation A,AX B,BX C,CX D Std. Datum Lgth One Set Code MachineThis slide shows the industry standard matching tolerance for V-Belts vs. Browning Code 1 match and Browning Machine Match standards. Belt matching becomes more important on long center distance drives which use longer belts.By RMA standards, belts over 62” can have a 0.3” or greater deviation in length for matched sets of belts. Browning only allows 0.24 on our standard Code 1 belts. On a 108.0” center drive, a 0.1” difference in belt length will cause a 2” sag in the longer belt.Browning standards are much tighter than RMA standards. Our machine matched belts are matched under load while running.* RMA = Rubber Manufacturers of America (also ANSI Standard)27
9 Replacement Dynamics Always replace with like or higher design. Different styles of belts may have the same dimensions, but mush different horsepower characteristics.Replacing a B for a BX or a 5L with a B Belt will lead to:Shorter belt life and continuing to install incorrect belt on drive.Never mix new and used of different manufacturers on the same drive.Cord location is different and may result in shorter belt life and maintenance issues with the unit.
10 Belt Design Life: Factors that can reduce belt life: FHP are:8000 HourDesign LifeClassical& 358 are:25,000 HourDesign LifeLooking at both the inside cover of the Reference Guide, it is important to note that 5L and B sections have approximately the same top width and will actually fit in the same groove. However, 5L and B section belts have dramatically different Design Lifes. FHP (5L) belts are designed for an average of 8000 hours of life, whereas Classical and 358 belts, such as BX and 5VX belts, are designed for an average of 25,000 hours life. In addition, not only do different cross sections have different design lifes, but they also have different horsepower ratings as we will now see.Different Cross Section have Different Design Life & Different Horsepower RatingsFactors that can reduce belt life:Excessive sheave groove wear & improper alignmentLack of proper tension of the driveTemperature: High Ambient or from a process
12 Proper Maintenance Important Poor Maintenance Cost Time! Time is Money!Doing the same or more with fewer people!Resources leave & don’t get replacedBudgets getting cut!Less money to do all the things in need to get done.Looking for Higher Return on What I do get to spend!Return on Investment to the Organization (ROI).
13 Safety First! Always turn off and lock out power source. Observe all other safety procedures.Wear required protective gear or equipment, based on site requirements.Loss of production hours.Critical System – Unscheduled downtime
14 What do you see once the belt guard is removed? Inspect the DriveWhat do you see once the belt guard is removed?Look at the drive elements – belts, sheaves, bearingsInspect belts for signs of failure:Glazing or cracked sidewallsUneven wear on sidewall of a beltExcessive belt dustCheck sheave alignmentInspect sheaveEven Groove wearBelts bottoming outAny bearing lubrication issuesExcessive heatInspect the blower for other problems
15 Inspect Sheaves on a regular basis Clean dirt or rust out of sheave grooveDirt and rust are abrasive to beltInspect for damaged or worn groovesCheck wear with groove inspection tool or straight edgeThe smaller sheave (Motor) will show wear first
16 When do sheaves need replacing? Check sheaves every time belts are changed.The smaller diameter sheave (usually the motor sheave) will always wear out first, typically needs to be replaced with every 3rd or 4th belt change.Sheave Groove WearBelt should never ride in bottom of grooveCheck for groove wear >1/32”Worn sheaves load on the end cords higher, lead to rapid belt failure and more frequent replacement
17 What happens with continued use of worn sheaves Loose adequate sheave sidewall contact. This can cause belts to slip causing excess friction & heat causing the belt to fail prematurely.Sheave walls become “dished” which reduces the ability of the V-Belt to wedge in the groove.Less contact between the groove and belt surfaces.Reduced air flow for the blower unit.The smaller sheave will always wear out faster. In many cases this is the motor sheave, this will change the drive ratio & reduce air flow.Belt cords are un-evenly loaded.Not much different than using a new and used belt or 2 different manufacturers belts on the same drive. Just internal to the belt.Uneven wear on multiple groove sheaves can create uneven load sharing across all belts reducing efficiency and possibly creating vibration and noise.
18 Aligning Sheaves4 point static contact with straight edge ensures alignment4 point static contact per side when using cord or stringCan use a laser, but they are expensive, need to be maintained and take a some time when variable pitch sheaves are involved.2008 Emerson Power Transmission, All Rights Reserved
19 Misalignment & V-Belt Angle Sheave should aligned within tolerance of specific style of belts:Wrapped Belts (FHP, A, B & 5V): ± 2˚Notched Belts (AX, BX, 3VX & 5VX): ±1/2˚There are 3 Basic Types of Sheave & Shaft Misalignment
20 How to correctly tension belts The good old “Thumb Rule”Deflect the belt about ½ inchToo little tension the drive till the belt chirps on start up!This generates heat and will cause belts to fail prematurelyToo much tension can over load the bearings!Excessive load can damage the motor and fan bearingsMove the sheaves as close to the bearings as possibleReduce the cantilevered load on the shaftsThis is what most technicians are using!+MotorBlowerWhat should be using!Accuracy and Consistency are Key!
21 Energy loss from Belt slip (result of poor tensioning) 98%Optimal82%Under-TensionedPercent SlipUnder-tensioned V-belts slip which causes efficiencyloss, premature belt wear and sometimes noise.
22 So why are Belts under tensioned? Belts that are “rolled” onto the sheaves without adjusting the motor base do not apply sufficient tension to prevent belt slip.Old belts are cuts off the drive and the motor base is not repositioned toward the blower the belt is forces over the rim of the sheaves.This damages the cores of the belt and if a screwdriver or pry bar is used, could create nicks in the groove of the sheaves.Worn sheaves don’t provide adequate sheave sidewall contact. The belt are pulled deeper in the grooves providing less over all tension to the drive. Belts go slack after being run for a little while. When they seat themselves in the groove of the sheave.Replacing belts and moving the motor base backto a “preset mark” does not ensure proper tension.Using an idler can help to apply tension but must be adjusted or re-adjusted to provide the proper force.
23 Installing NEW Belts Installing new belts: Use all the same brand on the drive.Never Pry Belts onto sheaves.Double Check Belt HP RatingVerify motor nameplate HP ratingExample: 1760 RPM
26 HVAC Fan and BlowersProper Belt Tension – 10-15% loss if under-tensionedBelt type – 3-5% gain by replacing wrapped V-Belts with raw edge V-BeltsMaintenance % loss can occur due to Sheave wearAsk to see our Energy Calculator that can run specificapplication for horsepower and by state.2008 Emerson Power Transmission, All Rights Reserved
27 Energy Efficiency for Different Belt Types Wrapped vs. Raw Edge Raw edge cogged V-Belts provide a higher coefficient of friction with the sheave groove wall. This creates less slip when the belts are properly tensioned.Raw edge belts directly replace wrapped belts (BX48 replaces B48).Raw edge belts transmit more Hp than the equivalent wrapped belts.Raw edge belts provide better sheave groove wall contact than wrapped belts, even when used with smaller diameter sheaves.
28 Energy Loss from Worn Sheaves “As a sheave wears, the belt fits more loosely in the groove, so loads don’t transmit as well. This causes an uneven load distribution across the belt tension member, with more load being applied at the belt edges. The effect is similar to that of high temperature.Because of this uneven loading, worn sheaves reduce belt life by as much as 50%. But their adverse effect on efficiency is even more costly. The efficiency of a belt drive with visibly worn sheaves and loose, slipping belts can easily drop below 90%. To translate this into operating costs, consider a 50-hp belt-driven machine that costs $25,150 (at $0.07/kWh) to operate year-round. The efficiency loss due to loose, slipping belts and worn sheaves costs about $1,300 per year, more than enough to replace the belts and sheaves several times” Power Transmission Design – June Neville W. Sachs, Salvaterra & AssociatesSheave Groove WearWorn sheaves cause more load on the end cords – and more rapid failureCheck for groove wear 1/32 “2008 Emerson Power Transmission, All Rights Reserved
29 How to correctly tension a belt If belt span is 32” then a properly tensioned new V-belt should only deflect ½ inch when 8.0 lbs. of force is applied.Deflection calculated: Span/64 in this example 32/64 = .5 or ½”If deflection is greater than ½ inch, more tension must be applied by adjusting the motor base.Each drive is unique.Move sheaves as close aspossible to the bearings.Reducing the overhung load &stresses on the bearingsSpan = 32”+MotorBlower8.0lbs.
30 Energy Saving Program Part II Drive Retrofitting
32 Retrofit Project: 50 HP Supply Fan Large Commercial PropertyManagement CompanyExisting Drive: 4 Groove C128 belt driveRedesign: 2 Groove 5VX1400 v-belt driveEnergy Savings: = Over $1300 per yearSolution: Expensive MVP Sheave on the motor & Companion Sheave on the Blower ALMOST 90% less than Existing DriveMotor Sheave Cost: $2,276Fan Sheave Cost: 1,113Total Sheave Cost: $3,390Total Sheave Cost for Retro Fit: $ 3503 ½ Month - ROI
33 Retrofit Project – 50 HP Supply Fan Cost Savings Example $959 per year in Energy Savings, using DOE 3% calculations$2000 Sheave Replacement Cost Savings, comparing existing drive to new driveExtend Belt PM Cycle from 12 months to 30+ months, annual belt cost alone is $340 – not including labor cost and time.Existing (4) C120 Belt Drive New (2) 5VX1250 Belt Drive
34 What can be done to optimize drive life? Properly tension belts.Use a tool for consistency and accuracy.Don’t use the “Rule of Thumb”.Check sheave for wear on a regular basis & replace worn sheaves.Always replace the existing belt with like or higher design.Upgrading belt design may even improve drive life.Make sure the drive in properly tensioned.
36 Auto Tensioning Motor Bases Spring Controlled Action Promotes greater efficiency.Compensates for variations in loadCompensation is obtained by combination of a one-piece movable carriage acted upon by a spring contained within the carriageCarriage design promotes superior alignment
38 SealMaster GoldPlex-SPL-EM FEATURES & BENEFITSOPERATING RANGEEFFICIENT LUBRICATIONOne GoldPlex™-SPL (EM) Can Service up to 8 BearingsUNIT CONSTRUCTIONHigh Strength Polymer DesignVARIABLE CONTROL PADControl Pad Allows for Variable Lubricant DispensingNo Need for Activator Keys or Control RingsGREASE CAPACITY125 cc or 250ccUNIT INSPECTIONClear Top for Quick and Easy InspectionCORROSION RESISTANCEGoldPlex-SPL (V) Unit Is Supplied With Clear Plastic Cover to Protect Variable Control PadGREASE TYPEFactory Filled with SealMaster GoldPlex™-HP Grease
39 Accessories – (V Unit Installation Kit) REPLACEABLE SERVICE PACKMULTI-BEARING CAPABILITYUnlike the V Unit, The GoldPlex-SPL-EM Model Allows for Fresh Lubricant to Be Added when Unit Grease Bladder Has Been Depleted.Using Divider Blocks, One SPL-EM Lubricator Can Be Installed to Service up to 8 Ball or Roller Bearings. Consult PPP-04 Catalog Installation Kit Selection.SPL-EMDivider Block(1) Replacement Grease Pouch cc or 250cc(1) Battery Pack(1) Disposable Dust Cover
41 Browning V-Belt Energy Efficiency Calculation I-Phone App Compatible with I-Touch and I-PadViral Campaign with Facebook page and LinkedIn promotionsMagazine Ad Campaign centered around App Release committed
43 Browning Toolbox Technician APP Where to Find Function
44 Connect With UsVisit our website for: Application Engineering contact information, installation instructions, product interchange softwareVisit our FacebookSearch Browning Belt Drives Save the Green. Join in on our belt drive conversations for energy savings and benefits.ThePowerTransmission for the latest product videos and trade show clips about Emerson Browning brand belt drive products and online tools.Download the Browning Energy Efficiency Calculator for your iPhone® or Droid®. Search “Browning vbelts”