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From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Technical comparison with formulas for the respective behavior of 40/50 HP and EAC governors.

Identifier  WestWitteringFiles\M\2Jan1925-March1925\  Scan12
Date  1st January 1925 guessed
  
-2-

GENERAL.

RESPECTIVE BEHAVIOUR OF 40/50 & EAC. GOVERNORS.

Let engine r.p.m. be n. R.P.M.
" pull from governor be X lbs.
" " " spring x lbs.
Rating of " " p lbs/1".

Let engine revs. fall by r.{Sir Henry Royce} R.P.M.

Then new pull of the governor = x((n - r)^2 / n^2) lbs.

Consequent movement of controlling spring end will be - x((n - r)^2 / n^2) ins.

Now on 40/50 HP. 1" movement at the end of the controlling spring gives the complete range of throttle opening.
. Fraction of total opening by which the throttle opening is increased for a drop of n. R.P.M.

[ x [ (n - r)^2 / n^2 ] ] / p

On the EAC. .4" movement at the end of the controlling spring gives 45° movement to the camshaft of throttle slow opening cam.
. Increase in camshaft degrees of rotation for a drop of n. R.P.M.

[ x [ (n - r)^2 / n^2 ] / p ] X [ 45° / .4" ]

but the value of 1° camshaft rotation as regards throttle opening varies from 1_o to 1'

Therefore in the case of the EAC. there is no constant fraction by which the throttle is opened for a drop of n. R.P.M.

contd :-
  
  


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