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Experiments comparing Lucas and Smith standard cut-outs.


Identifier  WestWitteringFiles\D\March1920\  Scan35
Date  5th March 1920
  
To R. {Sir Henry Royce} from Ck. {Mr Clark}
c. to CJ.
c. to E. {Mr Elliott - Chief Engineer}
c. to Bn {W.O. Bentley / Mr Barrington}
c. to Wor. {Arthur Wormald - General Works Manager}
c. to PN. {Mr Northey}
c. to By. {R.W. Bailey - Chief Engineer}
c. to Da. {Bernard Day - Chassis Design}
c. to Hs. {Lord Ernest Hives - Chair}
c. to EP. {G. Eric Platford - Chief Quality Engineer}

ORIGINAL

X.3770 - LUCAS CUT-OUT. X.1815.
X.3771. - SMITH CUT-OUT.

We have made experiments on two present standard Lucas cut-outs, also on the two Smith cut-outs, one of which was received with each of the two Smith dynamos, as follows :-

Taking the setting of the cut-out just as received from the makers (there is no adjustment allowed on the Smith cut-out, and the adjustment on the Lucas cut-out has recently been deleted by them so that no adjustment is possible) the cut-outs were first of all tested cold and the volts and amperes necessary to pull the cut-out into action and to allow the cut-out to drop out of contact carefully noted, with the following result :-

Just operated at Allowed to drop away at
Cut-out. volts. amps. ohms. volts. amps.
Lucas present
standard A, 13.1 .345 38.0 8.2 .21
Lucas present
standard. B. 15.5 .42 37.0 8.4 .215
Smith cut-out (1) 12.2 .100 122 8.4 .063
" " (2) 13.5 .069 196 10.1 .0475

Contd.
  
  
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).


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