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).
Letter to The British Thermostat Co. Ltd. regarding the testing and comparison of thermostats and heater motors.
| Identifier | ExFiles\Box 156\2\ scan0067 | |
| Date | 12th April 1938 | |
| 1328 April 12th.1938. Rm{William Robotham - Chief Engineer}/Std.3/AP. The British Thermostat Co.Ltd., Teddington Works, Windmill Road, Sunbury-on-Thames, MIDDLESEX. For the attention of Mr.Martin-Hurst. Dear Sirs, We have received your letters of the 1st. and 4.th.inst. for which we thank you. You have recently sent us two thermostats similar to the type made by Messrs S.Smith & Sons which we have already tested and are using at present. As we have such a thermostat in satisfactory operation already, we would like to know whether you are agreeable to supplying these two sample units on loan, i.e. without charge, for comparison with Messrs Smith's product. We would also like to know whether you have any record of the bellows free length of these units, as we wish to check up on any alteration with running - if not it would be advisable to return them to you for measurement and recharging of the bellows. With regard to the heater switches which proved faulty - these have been used to control a Lucas heater motor (particular type unknown), the power consumption of which is approximately 22 watts - we cannot understand your statement that they are only intended to dissipate 5 watts, since they are supplied with the Clayton heater, the consumption (maximum) of which is approximately 13 watts, while your own car heater motor, as tested by us, absorbs 16 watts. Incidentally we have unfortunately mislaid the sample plain bearing motor which you sent to Messrs John Marstons Ltd. and which was forwarded to us - we would be glad if you could let us have another one for comparison with the ball bearing motor which you sent us, and which we are now testing. At the moment the ball bearing motor does not seem very promising on account of its noise. continued | ||