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 report detailing the specifications and initial performance of a machine or motor.
| Identifier | WestWitteringFiles\H\November1921\ Scan17 | |
| Date | 11th November 1921 | |
| Contd. -2- EPCB/T11.11.21. Carcase diameter 5.00" length 1.740" thickness .30" Armature dia. 3.00" Active length 3.050" Weight of the machine complete but without pinion or suspension 23.75 lbs. Weight of armature without pinion 8.5 lbs. Air gap .050" - 1.27 mm. No. of wound poles 4 Arrgt. of coils - 2 series 2 parallel. Resistance of field circuit - .0019 ohm. (at 18°C). No. of armature slots - 15. No. of commutator bars - 15. Armature resistance .0060 ohm at 18°C. Commutator diameter 1.750" length 1.125" Brush contact area - 2 x .670 x .325 = .478 sq." Ratio of field to armature resistance .317 Length of armature overhang at driving end .75" Length of commutator connections (excluding spokes) 1.15" Ditto (including spokes) 1.4" The first brake test of this machine was attempted with our standard volt ampere characteristic of 1 volt drop from 12 volts per 50 amperes, but owing to the low resistance windings of this motor and the consequent large current taken, this characteristic was found to be distinctly unfair to the motor. Even on this characteristic, however, the motor did not behave at all well in the matter of commutation. The commutator and brush system were in distress. This we pointed out to the C.A.V. representatives and the motor was returned to them. They returned it to us again with different quality brushes and the commutator cleaned up. For further tests, we decided upon a Contd. | ||