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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).
Test results for a dynamo and switch system, noting operating voltages and RPMs.

Identifier  ExFiles\Box 59\1\  Scan237
Date  29th June 1920
  
RR 238 (150 BKS.) (SH57.29-6-20.) MP 224358
ROLLS-ROYCE LTD.
INSTRUCTIONS.
19
To
Order No.
Customer's No. 4

It was found that the switch operated when the dynamo reached 1850 rpm (25 mph) whilst the cut-out points were held open, the battery (connected to the switch shunt-coil) standing at 12.8 volts. The O.C. voltage of the dynamo at that speed being 22.0 volts; the temperature of the machine being intermediate throughout the tests.

Tests were next made using a Phantom dynamo (narrow-brush machine R) on the system incorporating the switch. Adjusted without the extra coil, the operation was:--

Volts to open Volts to close
17.0 12.6 Dynamo standing
12.4 " at 1550 rpm
12.3 " " 2500 "

Signed (Coultas)
This Sheet must be filed on completion of the work.
  
  


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