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).
Test report page detailing the methods for calculating belt slip and horsepower, with comparative test results for Dayton and Gates brand belts.
| Identifier | ExFiles\Box 135\1\ scan0243 | |
| Date | 8th November 1938 guessed | |
| - 4 - In addition to the vee pulley speeds taken with the stroboscope the motor speed was taken at the same time by means of a Haslar revolution counter. Other observations made were belt temperature on the sidewalls and base immediately the test was shut down, and ride out on the fan pulley. All these figures together with observations made as to the conditions of the belts are recorded on the detailed test reports. The method of obtaining the calculated results is as follows:- Vee belt slip % = driving vee pulley speed - fan pulley speed x 100 ----------------------------------------- driving vee pulley speed Flat belt slip % = motor speed x 3.404 - driven vee pulley speed x 100 --------------------------------------------- motor speed x 3.404 H.P. transmitted = Volts x (amps - 10) x 85% ------------------------------- 746 Dayton Cog. VC.17 Pulley diameter 3-21/32" " angle 33°56' Belt periphery external start 42-13/16 end - Belt periphery internal start 38-5/8 end - Initial centres 12.7 Fan speed 4000 - 4360 Driven speed 4100 - 4600 % Slip Initial 4.4 Average 4.7 Minimum 1.8 Maximum 9.8 H.P. 2nd fan 14.5 - 17 3rd " 20 - 23 Average H.P. (all test) 18.65 " H.P. hrs. 121.825 V centres adjusted 5 times to maximum V centre possible = 13.7" = 2" elongation Test stopped because excessive slip and all adjustment used, after 6 hours. Gates Vulco No.22316 Pulley diameter 3.875" " angle 34° 12' Belt periphery external start 42-13/16" after 10 hrs.27 mins. 43-1/16" " 11-3/4 hrs.(end) 43-1/4" " " internal start 38-15/16" after 10hrs.27 mins. 39-1/4" " 11-3/4 hrs.(end) 39-7/16" Initial centres 12-3/8" Fan speed 4060 to 4440 R.P.M. Driven speed 4240 to 4580 R.P.M. % Slip Initial 5.6 Average 2.0 Minimum 1.3 - continued - | ||