General Guide Lines
There are some general guidelines which are applicable to all timing belts, including miniature and double-sided belts:
Drives should always be made with ample reserve hp capacity. Use of overload program factors is essential. Belts ought to be rated at only 1/15th of their respective ultimate strength.
For MXL pitch belts, the smallest recommended pulley will have 10 teeth. For various other pitches, Table 8, ought to be used.
The pulley size shouldn’t be smaller than the width of the belt.
Belts with Fibrex-glass fiber tension members shouldn’t be subjected to sharp bends or rough handling, since this may cause breakage of the fibers.
In order to deliver the rated horsepower, a belt will need to have six or even more teeth in mesh with the grooves of small pulley. The amount of teeth in mesh could be obtained by formula provided in SECTION 24 TIMING BELT DRIVE SELECTION PROCEDURE. The shear strength of an individual tooth is only a fraction of the belt break strength.
Because of a slight part thrust of synchronous belts in motion, at least a single pulley in the travel should be flanged. When the guts distance between your shafts is 8 or even more times the diameter of the smaller pulley, or when the travel is working on vertical shafts, both pulleys ought to be flanged.
Belt surface velocity should not exceed 5500 foot each and every minute (28 m/s) for larger pitch belts and 10000 feet each and every minute (50 m/s) for minipitch belts. For the HTD belts, a quickness of 6500 feet each and every minute (33 m/s) is definitely permitted, whereas for GT2 belts, the maximum permitted rate 
is 7500 ft per minute (38 m/s). The maximum allowable operating velocity for T series is definitely 4000 feet each and every minute (20 m/s).
Belts are, in general, rated to yield a minimum of 3000 hours of useful existence if all instructions are properly followed.
Belt drives are inherently efficient. It can be assumed that the efficiency of a synchronous belt drive is certainly greater than 95%.
Belt drives are often a way to obtain noise. The rate of recurrence of the noise level raises proportionally with the belt rate. The higher the initial belt pressure, the higher the noise level. The belt teeth entering the pulleys at high velocity act as a compressor which creates sound. Some noise is the consequence of a belt rubbing against the flange, which in turn could be the result of the shafts not getting parallel. As demonstrated in Figure 9, the noise level is substantially decreased if the PowerGrip GT2 belt has been used.
If the drive is part of a sensitive acoustical or consumer electronics sensing or recording device, it is suggested that the back areas of the belt be ground to assure absolutely uniform belt thickness.
For some applications, no backlash between your driving and the driven shaft is permitted. For these situations, special profile pulleys could be produced without any clearance between your belt tooth and pulley. This may shorten the belt lifestyle, but it eliminates backlash. Body 10 displays the superiority of PowerGrip GT2 profile as far as reduction of backlash is concerned.
Synchronous belts tend to be motivated by stepping motors. These drives are put through continuous and huge accelerations and decelerations. If the belt reinforcing fibers, i.e., pressure member, as well as the belt material, have high tensile power and no elongation, the belt will never be instrumental in absorbing the shock loads. This will lead to sheared belt tooth. Therefore, consider this into account when how big is the smallest pulley and the components for the belt and stress member are chosen.
The decision of the pulley materials (metal vs. plastic material) is normally a matter of price, desired accuracy, inertia, color, magnetic properties and, most importantly, personal preference based on experiences. Plastic pulleys with steel inserts or metal hubs represent a good compromise.
PRECAUTIONS
The next precautions should be taken when installing all timing belt drives:
Timing belt set up should be a snug fit, neither too restricted nor too loose. The positive grasp of the belt eliminates the necessity for high preliminary tension. Therefore, a belt, when set up with a snug fit (that’s, not too taut) assures longer life, less bearing put on and quieter procedure. Preloading (usually the cause of premature failure) is not necessary. When torque can be unusually high, a loose belt may “leap teeth” on starting. In such a case, the tension ought to be increased gradually, until satisfactory procedure is attained. A good rule of thumb for installation stress is as proven in Figure 20, and the corresponding tensioning force is proven in Table 9, both shown in SECTION 10 BELT TENSIONING. For widths apart from shown, increase power proportionally to the belt width. Instrumentation for calculating belt pressure is obtainable. Consult the merchandise portion of this catalog.
Make sure that shafts are parallel and pulleys are in alignment. On a long center get, it is sometimes recommended to offset the powered pulley to compensate for the inclination of the belt to perform against one flange.
On a long center get, it really is imperative that the belt sag is not large enough to permit tooth on the slack side to engage one’s teeth on the tight part.
It is important that the framework supporting the pulleys be rigid at all times. A nonrigid 
frame causes variation in middle length and resulting belt slackness. This, subsequently, can result in jumping of teeth – specifically under starting load with shaft misalignment.
Although belt tension requires small attention after initial installation, provision should be designed for some center distance adjustment for ease in installing and removing belts. Usually do not pressure belt over flange of pulley.
Idlers, either of the inside or outdoors type, aren’t recommended and should not be utilized except for power takeoff or functional use. When an idler is essential, it must be on the slack part of the belt. Inside idlers must be grooved, unless their diameters are greater than an equivalent 40-groove pulley. Flat idlers should not be crowned (use advantage flanges). Idler diameters must surpass the smallest diameter drive pulley. Idler arc of contact should be held to a minimum.
As well as the general suggestions enumerated previously, specific operating features of the get must be considered.