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).
Tracking test comparing Bosch moulded insulation with standard bakelite for ignition coils.
| Identifier | ExFiles\Box 178\4\ img008 | |
| Date | 1st April 1932 | |
| R.{Sir Henry Royce} from HE/Wst. c. Sg.{Arthur F. Sidgreaves - MD} c. WOY. E.{Mr Elliott - Chief Engineer} c. EV.{Ivan Evernden - coachwork} Dn. He/Wst.9/ADB.4.32. X6110 BOSCH MOULDED INSULATION With reference to H1/HP23.3.32. addressed to R, we have carried out a tracking test on a sample of this latest Bosch moulded material taken off one of the latest Bosch ignition coils. Our tests consisted of arranging a spark gap across the surface of a sample of our own standard bakelite material and a sample of the Bosch material and allowing hot sparks from a magneto running at 1500 R.P.M. to transverse the gap over the insulation surface. We found the Bosch to be slightly better than our standard as regards the time taken to track across but the fact that tracking occurred showed it to be synthetic resin moulded material. The Bosch tracked and broke down after 3 secs. whereas our standard broke down almost immediately. Chemical and burning tests also show this Bosch material to be a pure synthetic resin moulding with the recognised iron oxide filler. The only advantage, therefore, of this Bosch is that it is slightly better than our standard material for tracking, but it is still a long way behind the rubber base mouldings in this respect. HE/Wst. | ||