Strange (to me) balance spec
Strange (to me) balance spec
(OP)
Can someone decipher what this balance spec is.. or was likely intended to be. From a drawing of the part.. "Dynamic balance @ 190 RPM to maximum 4 oz force"
Do they mean.. a final correction of less than 4 ounces? 4 ounce inches of unbalance?.. Dynamic implies two plane.. this definitely is a static balance job. I have come across a lot of varieties when it comes to balance specifications but this one has me scratching my head.
The part... an agitator (cast), 36 inches in diameter and weighs 2000 pound that spins at 145 RPM.
Do they mean.. a final correction of less than 4 ounces? 4 ounce inches of unbalance?.. Dynamic implies two plane.. this definitely is a static balance job. I have come across a lot of varieties when it comes to balance specifications but this one has me scratching my head.
The part... an agitator (cast), 36 inches in diameter and weighs 2000 pound that spins at 145 RPM.





RE: Strange (to me) balance spec
4 oz=1N, so the maximum residual imbalance is 2.5 kg mm
Does that make any sense?
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Strange (to me) balance spec
Metric tolerances confuse me, is that translatable to an ISO 1940 spec? or something in gram inches.
Then I don't know how one would measure that force at the bearings... the bearings are 48 inches apart.. the shaft (solid coupling) is 16 feet 3inches long and the thing spins vertically.
I am currently balancing them (5) overhung and mounted on the shaft.. to an ISO G16 spec (38 kgin)
RE: Strange (to me) balance spec
Although thinking about it that's the imbalance force applied to the rotor, it only gets through to the bearings if you assume everything is infinitely stiff.
2.5 kg mm=2500 g mm=100 g in=3 oz in
sorry I don't know about your specs.
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.