Question

A reciprocating air compressor has a 5-ft-diameter flywheel 14 in wide, and it operates at 170 rev/min. An eight-pole squirrel-cage induction motor has nameplate data 50 bhp at 875 rev/min. (a) Design a Gates Rubber V-belt drive to transmit power from the motor to the compressor flywheel. (b) Can cutting the V-belt grooves in the flywheel be avoided by using a V-flat drive?

Answer 1

SOLUTION = 6o in 14 in wide rim Hnom 5O hP n = 875 rev/min ks=. 2. SL8 170 mar 60 5.47 1in Aheave From Tabk standad V-belt ecions, an diametir amd precludes exceeds minimum C-Section E section V-belts D amd Decision d =in use C 270 belts Conversion di mens'ions From tabl length Lp 270 +2.9 272.9 in Lp d20- + Lp O-25 2 (60-11) +11) O-25 272.9 272.9 C =76.78 in

This pits in the rang DC 3 (D+d) 60 C< 3 (6o t11) 212 in 6o in < C 60 Od= TT -2 sin" 2(76.78) Od 2.492 rad 60- 7 2 sin 2076.78) D 3.79 Yad cosicient af fviction The esective f = o.5123 exp (fo)=exP(0.5123x2.4.92) Exp (fo)= 3.5146 flywht lat on For the exp fe)= exp [o-13 3791) Jab37 Tdn - Tx}IX8TS 12 2 ft/nin V= 2519.8

From tabe amgl af cotact corvection factor k for omd V VV flat dive For Od = 2.42 Yad Pegression equation gives ki O.9O From belt lengih correction factor for pelt C270 From horse rati'ngs of tandad v-belts po we 7.83 hP/pelt by inta polation Htab Ha k, k2 Htab Ha O.9o5 x ).IS X 7.83 hy Ha = 8. Hd H nom Ks nd Hd 50 x ).2 11 6 6 hp Hd 2 N Ha N= 1,2,3.... 66 Hd Nb Ha 8.S Nb 9 helts 63025 x 8. i 63025 H nd/h A Fa = g75 C2) A Fa = 106.7 /bf/belt

Ta =AFad 2 06.7X Ta 2. Ta 5869 (bf poi belt 2 V 1.76 25 19.8 Fc = 1.76 OOO FC 10.9 bf/bet frictiongives At fully deelo ped Fi= exp (4e) -) 3. 586 F- 586.9 3.sg46 94-6 bf/belt exp() 2 F=F + Fi o.9 9L.62(3.5 846 3.5846 t Fi 58.8 f/belt F =

F2=Fi- AFa F701 -8' 8SI - 7) F2= 52.b/pelt Nb Ha 9x 8.5 Hd Dura bality (FD 45. 45 b/belt = 76.7 b/belt (Fb) 304.4 b/belt - 85.6 t/belt T2 t 1soooo h Remembe (Fi)doi ve = q x 94..6 F)durive f9y IS8 = V -belt eelions Standard belt aore C Section Apocing chack heave to see wide groove dating l-wid LS acco mmo

the ma Aats of the V-belts is (b The fully daveloped riction On wing 4lywhee Hhe exp Tlat A F .637-1 THlat .637- Tlat - 1371 bf.in po bel E The hywheet torque shoudd be Ty 5.17 (586.9) ma Ta 302 bf.in pei belb There applications , howaven, But it not aJce in which * will eRam ple work For ma ke controlli ng Yes flywhe