10.07.2015 Views

friction clutches - Arten Freios e Embreagens Industriais

friction clutches - Arten Freios e Embreagens Industriais

friction clutches - Arten Freios e Embreagens Industriais

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Table of Contents◗FUNCTION EXAMPLES“Air Champ” ®CYCLING (OR INDEXING):Continual starting and stoppingis very hard on motors andstarters, Motors must then beoversized and even then, theyhave limited cycling capability.A clutch/brake reduces the loadby letting the motor run continuously,permitting much fastercycling rates ... (often morethan 100 times per minute)with only fractional power.◗ “AIR CHAMP”PRODUCT CONSIDERATIONS:◗ SELECTION CONSIDERATIONS:Rotational inertialCycle rateTransmitted horsepowerRPMTorqueContinuous Thermal HorsepowerRating◗ EXAMPLESelect a clutch-brake for a drive in amachine that die cuts paper board intocartons. The clutch is used to drive rollsthat feed lengths of paper board to thedie cutting head at rates up to 46 timesper minute. The brake stops the feedrolls every cycle.◗ UNIT SELECTED:The drive consists of a 1 horsepower,1800 RPM motor going into a 10:1 wormgear reducer. A Modular clutch-brake,MDB-625, is selected from the NEMAFrame Selection chart in the catalog.MBU-625 Product Number 928500MDU-625 Product Number 928600This application is classified as a cyclestart-stop and requires an evaluation of thecontinuous thermal dissipation capacity.◗ THERMAL CHARACTERISTICS:Calculate the continuous thermal horsepower(HP T ) requirement based on thereflected inertia, speed at the clutchbrakeand the cycle rate.◗ ENERGY PER CYCLE:E c = .00017(WK 2 )(RPM) 2 =.00017(.195)(1800) 2 = 107.4 ft. lb.Where: E c = Energy per cycle in ft. lbs.WK 2 = Reflected inertiaRPM = Speed at the clutch-brake◗ THERMAL HORSEPOWER REQUIREMENTS:HP T =E c (CPM) =107.4 (46) = .1633,000 33,000Where:HP T = Thermal horsepowerdissipation requirementE c = Energy per cycleCPM = Cycles per minuteRefer to the Thermal Capacity of ModularUnits on page 249.An MDB-625 dissipates .40 thermalhorsepower continuously at 1800 RPM.D04133441BWCB–HWCBFCDB–HCDB◗ ROTATIONAL INERTIA:The value of WK 2 of the two 15 inchdiameter, one inch wide feed rolls istaken from the Inertial of Steel Discs andShafts chart on page 361.Wk 2 = 9.75 x 2 = 19.5 lb. ft 2◗ CONTROL CIRCUITThis application utilizes two 3-way normallyclosed valves.One valve is used to cycle the clutch forthe feed operation. The other 3-way valveis energized to apply the brake.◗ REFLECTED INERTIA (WK 2 r):REGULATORPROD. NO.940001D03133440MODULARCLUTCH/BRAKESMDB625–1375WK 2 r = WK2 ( N 1 )2 = N cbFILTERPROD. NO. 9391013-WAY CONTROL–N.C.PROD. NO. 94900219.5 ( 180 ) 2 = .19518006133443D04145470FMCB–130–19 AND 24FMCB–7–28 AND 38FMCB–8–38 AND 42FMCBE ANDFMCBES625, 875, 1125,1375Where:WK 2 =Feed roll inertiaN 1 =Speed of the loadN cb =Speed of the clutch-brakeREGULATORPROD. NO. 940001LUBRICATORPROD. NO. 939201D05145471382

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!