# What is the coupling used for? How much do you know about the selection of the coupling?Part 3

- Sep 21, 2019-

1. Firstly, according to the requirements of mechanical characteristics, if there is no backlash, high to low torsional stiffness, vibration shock absorption, etc., choose the appropriate coupling type.

2. The torque of the coupling is obtained by the driving machine (such as motor) [KW, HP] and the coupling using the number of revolutions [N] [TA]

TA(Kg.m)=973.5×KW/N(rpm)=716.2×HP/N(rpm) or TA(N·m)=9550×KW/N(r/min)

3. From the positive coefficient table, find the load condition coefficient K1, the running time coefficient K2, the starting stop frequency coefficient K3, and the ambient temperature coefficient K4 to obtain the correcting torque [TD].

TD=TA · K1 · K2 · K3 · K4

4. The common torque used for the coupling must be greater than the positive torque.

5. The maximum torque that the coupling can withstand must be greater than the maximum torque generated by both the primary and passive sides.

6. Determine if the aperture range is applicable.

7. In addition to the above selected steps, the vibration frequency must also be reviewed. That is, the frequency of the torque fluctuation and the natural vibration number of the shaft avoid the occurrence of resonance.