Document Q1BBRKXwy33ykLe9wrmkgpL7

Whether new or old, mechanical power-transmission equipment needs.. Planned lubrication of Trantmlulon Equipment h * men who operated machines were often (killed .t.^frein ^ lubricated end rooiruoined their own unite. TTiey have been lubrication experts, but ihey did here (ingle* ' ' J. mA. int_e__re__sit Iint baaccnplAwOa t*he'm* I*f"lil*l*fl*. Wep Ai industry became larger and more ipecisltied. f/--'^nanee tended to separate from operation. And, unfortu* lubrication loo often drifted off Into an Independent chore V-'-'-k-. *ot Utile "! attention from anybody. "Oiling" became a ` flocw&wlkkiUill llootw**-ppayy jjoobo wwiitmh liimttliec ImnccoennutiTveo.. To.day, lubrication `'t'""in- s..ets. rels.t.l.w___n_eiw.coiImiaerskMloifMthiieAnpkrlofftea1fiitonaerl* fiaelAldn,* are step- 'V7*V jnUp (he picture. They're making lubrication an organised, y,?5uii (unction that will pay of! In longer maehlno lile. Orpanltinp. Bed way to tackle the job of modernising lubrica tion practice in your plant is to think of it as a separate function in the maintenance setup--not as an odd job to be dona In spare time. Approach varies, depending on whether the lube group la being set up in a new plrnl or an existing one. fttort Corly, In a new plant, the lubrication engineer in charge should work closely with designers, keeping them on the beam ' as lo operation and maintenance. In this way mosl-eOcctive lubri cation equipment can be ln;talled at me atari and tha whole ydem coordinated for best working results. In an eliding plant, you'll have lo move step by step, but goal is the same--efficient, economic*! lubrication. ...Planned Maintenance for A Longer Life Span By JIM SPARKS fdmenfon, Cenedo Belts. > Smart maintenance transmission-wise shows up as a twofold dollar savings. These savings come in reduced power bills, when transmission losses are cut, and in lower operating cost when belt replacements are fewer. V-Befis. There ore several possible trouble sources here that you should watch for in your maintenance pro gram: (I) too few belts on o single drive (2) sheave diameters too small for belt cross-section (see Power, Nov '52, p 112) (9) ehesves that have incorrect groove ongle for specific bell (4) belts that run too fed . . . keep belt speed below SOOO fpm (S) belts of wrong con struction used for a given application. Tension Is an important angle In Vbelt maintenance. Ever play Crack-the* Whip qs a kid? Chances are you ate supper off the mantle till you realized the tremendous snapping force a whip ping action can produce. And if your Couplings____ Proper alignment ranks well up on the flexible coupling maintenance list. Coupled shafts will transmit power at a higher efficiency where the shafts ore perfectly in line. Flexible couplings ore designed lo compensate for unavoidable misalignment that creeps in after shafts are coupled. Bearing failures and shaft fatigue--because of alternate compres sion and tension of ehaft's surfaceresult from excessive misalignment. Another common trouble eause sprouts from selecting couplings too V-belt hasn't enough tension, you'll get the some snapping action. This will happen more often at peak loads or when starting the motor. Any extra slack U suddenly taken up, and the last section of V-belt to be whipped taut is jerked with a force far greater than it was designed to stand. This is the reason why a loose V-belt in service will stretch more than a tight one. So don't be afraid to pull V-belts light. Stretching them slightly is good for their general health. Check often for stretch and sag, especially during the break-in period. A slack V.belt feels dead when you thump it with your hand, a properly taut P-bclt has an alive springiness. And while you're thinking about ten sion, check sheave alignment occasion ally. A straightedge will do, or in a pinch, a cord. Just stretch it across the sheave faces nnd see that It touches small for the application. This usually results from not giving proper attention to load characteristics and the power unit. Centrifugal pumps and tons under normal conditions represent s fairly steady load and cause little coupling wear. A plunger pump, on the other hand, represents a load that varies with the position of pistons and Is continually subjecting couplings to shocks. Conse quently. the coupling selected for the latter application must he large enough to meet the more severe conditions. Chains_______ all the four possible points of contact^ *"`-7 * You'll find power-transmission chain Laurher Bolts. Hera are a few maltf l.v.'li, practically alt kinds of power jobs. tenance tips regarding leather belts)] >*i its great strength permits transmitting First, standardize on as few belt widths'., /V.tfrge power with small cross section. and plies ss economically meet ptantA T'v And; it can run in temperatures that requirements. This cuts down variety? of spare belting that must be carried la]i y : would quickly destroy belts. It ia made 'VlnVfniny forms, but let's call our shots slock. Belt should not slip or creepy l*. here and concentrate on finished-steel- more than 29b of total belt length. FHe-T\ ijf roller'designs. You can adopt much of tionsl heat, created by too loose a beltf] V' .the'-info to other chain drives. bums and cracks belt surface. '$ Position. On short- or normal- Where excessive tension is needed toK center drives, the slack side of the chain prevent belt slippage, substitute a wood.) may be either on top or bottom. Slack or fiber pulley for the small itecl one.'$ >if strand runs better on the`bottom, be- Belt tension can be reduced by lagging^ r-ifcsuse a loose top strand tends to dla- small pulley with leather, rubber or,A J, ["'engage the drive sprocket teeth. On long duck. ^ Excess crown on a flat pulley mW ^Bearings_____produco strains along belt center line^ and oause prematura failure. Have pul-Jt ley face to 2 in. wider than belUj Save transmitting power by checking^ WJi^jBearihgi fall Into two closses; sliding that transmitting pulleys are In line, r flJRJqe* nd rolling contact. The former yi.`l.are-aUo known aa.pliin bearings, while *. V^?.'l-l,.Wer.,nty b* ball, roller or needle .s'^.kwlpgs. Operating engineers have ipenl many years with the elidlng-con- /^.'ci-type bearing for power-plant auxll- Where couplings are to be used for vj !'.kriw. nd are generally quite (amlllar reversing service, give extra thought to:'{ good maintenance procedures. So the type selected. For instance, don't 1 jjylet'i skip over to the rolling contact use couplings with considerable bsck-' lash for such an application. If re-.^ versa!* are frequent, select a coupling * large enough lo stand the service. Where couplings are for use with braking ac-,, n(l tevlew some proved field* >ta*!^n*enance procedures, i: Tu don't need to handle roll* '' '' k "Cnl*Ci bearings like antique china, rt*L,ne'y- do need proper care. They're lion, as on cranes and hoists, lake ae- . i.-Jtdohfcm.nud. and this precision must count of these conditions and use * ' ' irmf^ 'brdugbom their useful life. nraprr service factor. Correct service, i 1-3^ *n,Pctmg an old bearing. look factors sre eenerally listed In manufae- A vf-:;'0-Vcl"33've hardened areas. Streaks Hirers' catalogs or lechniesl bulletins..', lt the giveaway. Check fT centers, to prevent the strands rubbing together, have alack strand on bottom. Avoid vertical drives where possible. But U you must use them, keep them fairly tight by frequent adjustment- You can reduce the eare and adjustment 'needed if you Install the drive slightly ofl vertical. Alignment. Accurate alignment for any chain drive is an absolute must for trouble-free operation. Make the shafts, to which the drive connects, level and parallel, and the eprockets in line. You oan. cheek sprocket alignment with e string or straightedge held against their sides. As with belt pulleys, locate ohain ctacked parts,' etching resulting from contact with odd, discolored arena caused by overheating. .Any of these should cause rejection. For a complete picture story on why ball bearings fail, see Power, May 1951, p 116. Bearing removal can best be done with a set of bearing pulfers. They look and work like gear pullers. Apply pulling force on the Inner ring that hugs the shaft. Don't tug on the outer race. Putting the bearings back on usually calls for a press and a pipe sleeve. After lining up the bearing, select a sleeve the diameter of the inner race. Put this sleeve between the Inner race and .the press. Apply even pressure and she'll slide home. But instslllng some bearings may be tough work. It may eall for heating sprockets as nearly as possible to ahaft bearings. To avoid excessive vibration mount motors and shafting rigidly. Don't run 'roller chains with both strands tight. For best results have cen ter distance between sprockets adjust able, to take up slack caused by wear. There ft no definite rule for tension in a chain drive. In horizontal and inclined drives, normal practice allows a sag (when running) equal to about 2% of the center distance between sprockets. This (s more than that used on belt drives. Bui it works well. On loads that fluctuate badly, run chain tighter to reduce flopping when chain fs moving. the bearing in hot oil, and using special equipment to raise and lower it. Heat ing Inner race to between 200 end 250 F gives a good shrink fit. Sometimes it's more convenient to use dry Ice. end shrink the shaft. This allows the bear ing to slide easily onto the shaft. We Slipped ... a uttu Some copies of the December Issue were off the press when a typograph ical error on p 132 wot spotted. In the second paragraph of the short article, "Hlgh-Tempersture Cresses Lei Motor Run ! ISO C," the equiva lent of 150 C was listed ss 202 F. It should have been 302 F. i114 POWER JANUARY IfSJ * JANUART 1953 113