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Technical notes and specifications for the Goshawk dynamo, including details on armatures, current-density, brush-gear and brush spans.


Identifier  ExFiles\Box 50\5\  Scan314
Date  5th June 1924
  
X 4-383

5.6.24.

GOSHAWK(Aero Engine)(Codename for 20HP Car / Aero Engine after Kestrel(Aero Engine)) DYNAMO NOTES. X4383
X4633
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Expl. Std. and thick carcase armatures.
Resis. std. .347 ohm "Th.C" .365 ohm. Diff. .018 ohm
Ratio 1.05. Armature active length, standard 2.8"
(helically). Th.C. 2.75".
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Gos. dynamo brush current-density.
Area = .75" x .3" = .225 sq.". Main current (+) = about 16A
". Density about 70A/sq."
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Gos. dynamo pressed brush-gear, clearance from comm.
by drawing - .075"
Ditto Scintilla on actual machine (2057) approx. .125".
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First Gos. dynamo with retarded comm. No.383.
Goshawk(Aero Engine)(Codename for 20HP Car / Aero Engine after Kestrel(Aero Engine)) brush spans.
On one coil per slot machine .3"(main)= 1.32 segments.
" two " " " " .2"(control)= .88 "
" " " " " " .3"(main) = 2.59 "
" " " " " " .2"(control &) 1.73 " (mod'fd. {Frank Dodd - Bodies} main)
" " " " " " .125"(modif'd) 1.08 " (controb)

Goshawk(Aero Engine)(Codename for 20HP Car / Aero Engine after Kestrel(Aero Engine)) pole-shoe displacement.
.25" of pole-shoe, equiv. to .374" on carcase (for brush adjustment).
Goshawk(Aero Engine)(Codename for 20HP Car / Aero Engine after Kestrel(Aero Engine)) 2 coil/slot brush position is 3.5° less retarded
than std. 29 segment arm: = 3.5° more than old 29 segment.
Correct std. brush (main) position on Gos. dynamo.

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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