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).
The hot and cold bursting test of a moulded commutator to determine failure points.
| Identifier | ExFiles\Box 39\3\ Scan230 | |
| Date | 4th July 1924 | |
| EFC. WA.{Mr Wallis}57. X3573 4.7.24. X.4333. MOULDED COMMUTATOR BURSTING TEST. X3573 This commutator is of a different construction from the old moulded ones we tested a considerable time ago, and is described by W.Y. in EY19/H13.6.24. It has been run at high speeds both in a cold and hot condition to find out its ability to withstand the centrifugal force exerted, i.e. the force tending to separate the rotating masses, e.g. segments. The results are as follows:- Cold condition. The commutator was speeded up to a speed of 6300 r.p.m. and maintained for 2 mins. without failure. Hot condition. Temperature attained before disconnecting heater for running - 105ºC. Commutator accelerated up to and maintained at 6300 r.p.m. for 2 mins. without failure. The heater was again connected to raise the temperature approximately the same, (temperature attained before again disconnecting - 109ºC). After the commutator had been running for ¼ min. at 6300 r.p.m. four segments flew out. From the above results it will be seen that temperature is the main factor which causes disintegration of the moulding of this commutator a fact which is noticeable in results obtained with other moulded commutators. EPC/HEW. (See X 4333) | ||