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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).
Specifications for new designs of 40/50 and Goshawk dynamos and motors, including dimensions and performance requirements.

Identifier  ExFiles\Box 35\4\  scan 014
Date  3rd March 1921
  
X.4384
EFC/T3.3.21.

X.294.
X.543. NEW DESIGNS OF DYNAMOS AND MOTORS. X.3534.

The outside carcase dimensions settled upon by
Mr. Royce during my visit were as follows :-

40/50 dynamo = 6"
40/50 motor and Goshawk dynamo = 5¼"
Goshawk motor = 4¾"

The corresponding armature dimensions are :-

40/50 dynamo = 3.5"
40/50 motor and Goshawk dynamo = 3"
Goshawk motor = 2.75"

We want the 40/50 dynamo to cut in at 400 average
temperature, to give the full output of 10 amps. at 15 m.p.h.
maximum output to be 12 amps.

Carcase diameter is 5¾"

For the Goshawk dynamo we want 7 amps. average,
9 amps. maximum, 5¼ amps. minimum. Carcase diameter 5".

What would be the cost of manufafture of these
dynamos ?

X.3526 - 40/50 dynamo.
X.3533 - Goshawk dynamo.
X.3082 - 40/50 starter motor.
X.3534 - Goshawk "

It is suggested that an armature with 26 slots,
51 sections, two coils per slot, and therefore one dummy coil,
be used. The air gaps should be -

4.5 for the 40/50 dynamo
.012" for the Goshawk dynamo
.015" for both motors,

measured radially.

Contd.
  
  


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