The Complete Guide to Chain

# 4.1.2 Coefficients Used in Selection

1. Multiple strand factor
In multiple strand power transmission chains, the loading is unequal across the width of the chain, therefore, the transmission capability is not a direct multiple of the number of chains. You must use a "multiple strand factor," which is shown in Table 4.1, to determine the correct value.
2. Service factor, Ks
The chain transmission capability is reduced if there are frequent or severe load fluctuations. You must apply the appropriate factor based on the type of machine or motors (Table 4.2).
Table 4.1 Multiple Strand Factor
Number of Roller Chain Strands Multiple Strand Factor
21.7
32.5
43.3
53.9
64.6
Table 4.2 Service Factor
Type of Impact Machines Source of Power
Electric Motor or Turbine Internal Combustion Engine
With Hydraulic Drive Without Hydraulic Drive
SmoothBelt conveyors with small load fluctuation, chain conveyors, centrifugal blowers, ordinary textile machines, ordinary machines with small load fluctuation.1.01.0 1.2
Some impactCentrifugal compressors, marine engines, conveyors with some load fluctuation, automatic furnaces, dryers, pulverizers, general machine tools, compressors, general work machines, general paper mills. 1.31.21.4
High impactPress, construction or mining machines, vibration machines, oil-well rigs, rubber mixers, rolls, general machines with reverse or high-impact loads.1.51.4 1.7
1. Chain speed coefficient, Kv; sprocket tooth coefficient, Kc
Adjust the transmission capability according to the chain speed and number of teeth in the small sprocket (Figure 4.6). The sprocket coefficient is labeled Kc.
2. Impact coefficient, K
This coefficient (Figure 4.7) is based on the inertia ratio of the driving machine and driven machine (ratio of I, ratio of GD2) and the amount of play in transmission equipment. When the inertia ratio is less than 0.2 or greater than 10, use the value of 0.2 or 10, respectively.
Table 4.3 Unbalanced Load Factor (Ku)
Lifting Strands Factor
20.6
40.36