This section applies to belt and chain drives and such gear drives as transmit radial forces to the motor. Whilst the previous sections apply mainly to direct flexibly coupled drives, the importance of correct alignment for non-direct coupled drives must not be overlooked. When a flat belt drive is used, the joint in the belt should be smooth and flexible, and the pulley, avoid vertical belt drives, and belt drives with short centre distances (less than four times the diameter of larger pulley), if no killer whools can be provided.

Ensure that all load carrying and stressed elements are correctly fitted and located in their normal working areas, otherwise excessive wear and other problems will develop. This condition requires that the middles of the driving and driven wheels are aligned and that their shafts are parallel. The last requirement is satisfied if the distance between the shafts measured at two different places along the axes of the shaft is the same. The middles can be aligned without difficult with the help of a straight edge.

For flat belt drives the alignment of middles of the pulleys and parallelism of the shafts can be checked as follows. The set is run by starting the motor. If the shafts are parallel but the pulleys are not directly opposite, the belt will run to one side of the larger pulley. When the pulleys are opposite but the shafts are not parallel, the belt will run to one- side of the smaller pulley or will run off completely. Suitable corrective action should be taken after stopping the motor.

Fit belts or chains of the correct length required. This length is approximately equal to double the shaft centre distance plus 1.57 times the sum of the diameters of the driving and driven wheels. Short centre distances for belt drives result in excessive radial pull and they should, therefore, be avoided.

NOTES
1. The number and/or size of belts required should be determined by referring to supplier's literature.
2. Do not fit belts over the pulleys by stretching them with a lever as this may damage the belt. Get them over the pulleys by rotating the latter by hand.

7.1Application check for non direct coupled drives All non-direct drives requires special attention with regard to the following points.

7.1.1Capability of the motor to bear the radial pull on load Where a drive can transmit thrusts of any kind, radial or axial, to the motor, this must be made known. In general, larger machines are not designed to be suitable for such drives, and therefore an application check is essential. A high external load on the shaft will required the support for the driving wheel to be augmented by an external pedestal mounted bearing, or in extreme cases by an independent jack-shaft arrangement. A thorough application study is necessary BEFORE ordering the motor.

7.1.2Capability of load transmitting agent Capability of the load transmitting agent must be checked by its manufacturer, who must recommend all details regarding the same as well as wheel dimensions. For simple belt drives a preliminary check of this kind is also made by the Company's Design Department