Quote:
Originally Posted by Tristan Lall
John, do you have any information about the test conditions used to establish the 81%? And how much does that vary? (I've always made a similar approximation, but I don't have any hard data to back it up.)
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About 8-9 years ago when I was teaching myself this stuff I designed a drive using 81% as a magic number (I think someone on the forums mentioned this) then tested it -- the experimental matched the theoretical. It has just sort of turned into a "rule of thumb" for the typical style of drivetrains. I know some will be a touch slower and some will be a touch faster, but I've never been pissed off if I design at 81%.
I'm humiliated by how unscientific this is, but it seems to work for me.
I don't have hard data... just 9 year old, soft data...
-John