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).
Continued procedure for testing voltage, amperage, and resistance of a dynamo's shunt coil and cutout contacts.
| Identifier | ExFiles\Box 50\1\ Scan172 | |
| Date | 28th August 1922 guessed | |
| -2- Contd. this instant, shall be noted. The former shall lie between the limits 12.2 and 12.8 volts, and the latter shall not exceed .20 ampere at 12.5 volts, i.e. shunt coil resistance must exceed 62.5 ohms. If the cold operating voltage does not fall within the specified limits, a slight adjustment of the control spring of the contact lever should be made. (5) The dynamo shall now be speeded up momentarily to allow a charging current to flow into the battery, after which the speed shall be reduced until the ammeter A reading is zero. The connections to this ammeter shall then be reversed, after which the speed shall gradually be reduced still further until the cutout contacts fall apart. The instant of falling away will be shown by the drop to zero of the needle of the ammeter A. {Mr Adams} The readings of the voltmeter and ammeters immediately preceding this instant shall be noted. The reading of the ammeter A shall not exceed 2.0 amperes. In the unlikely event of this reverse current being exceeded, it is probable that the back air gap (i.e. the one over the series coil) is too small and should be increased. EFC. {E. Fowler Clarke - Electrical Engineer} | ||