Machine Drivetrain Efficiencies
Machine Drivetrain Efficiencies
(OP)
Machine Drivetrain Efficiencies
What is best way to determine the sum of machine drivetrain efficiencies?
Example:
20 hp motor driving a gearbox (98% efficient), which drives a timing belt (89% efficient) which drives a roller chain(89% efficient). What is total efficiency of the drive system?
See attached file.
What is best way to determine the sum of machine drivetrain efficiencies?
Example:
20 hp motor driving a gearbox (98% efficient), which drives a timing belt (89% efficient) which drives a roller chain(89% efficient). What is total efficiency of the drive system?
See attached file.





RE: Machine Drivetrain Efficiencies
However, until then, at least a rough estimation could be obtained through the "square root - sum of the squares" method: √(ηg2 + ηt2 + ηc2)
where the subscripts refer to the gearbox, the timing belt, and the rolling chain, respectively.
Patricia Lougheed
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RE: Machine Drivetrain Efficiencies
And I can't see how "square root - sum of the squares" would work with the figures quoted, as you appear to end up with a number greater than 1 ???
RE: Machine Drivetrain Efficiencies
98% of 100% is 98%
89% of 98% is 87.2%
89% of 87.2% is 77.6%
etc, etc.
You don't magically make up for lower efficiency with a higher efficiency, it still lowers the overall, just not as much.
James Spisich
Design Engineer, CSWP
RE: Machine Drivetrain Efficiencies
You're right -- that's what I get for giving an off-the-cuff answer. The SRSS doesn't work for percentages.
Patricia Lougheed
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