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).
Experiments to modify a motor's teaser winding to improve armature engagement.
| Identifier | WestWitteringFiles\Q\2April1927-June1927\ 99 | |
| Date | 10th May 1927 guessed | |
| -5- Contd. range, when tried on the bench with a battery. Our machine does not go definitely in. It would appear that there is still some longitudinal pull on the Bosch armature when it is right up against the stop corresponding to full engagement, as if the armature were not symmetrically between the poles. In our case, the armature apparently would be symmetrically between the poles when in full engagement, so that there is no force to balance the tension of the spring in that position. It may be considered that it is not necessary for it to have complete engagement as long as the armature operated switch is operated, but we still feel that there is not sufficient margin here. In an attempt to make this motor work, as it stands, but with small alteration, we are bringing out the mid-point and negative end of the teazer winding, so that these may be temporarily connected as desired. Putting the negative end of the teazer direct to earth will constitute one experiment, in which case the pull in will be more decided but the motor may not necessarily engage, and the frictional effect, after engagement, will be absent. Purely as an experiment we shall also try the effect of taking the mid-point of the teazer winding to the main motor terminal at the same time as having the negative end of the teazer put up to earth. In this case some of the armature current will be bye-passed on teazer operation and in the main operation the teazer becomes compounded. It is difficult to Contd. | ||