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 from Hasler Telegraph Works discussing the testing and adjustment of Hasler Revolution Indicators.
| Identifier | ExFiles\Box 165\4\ img244 | |
| Date | 27th April 1934 | |
| TELEPHONE N° VICTORIA 7575/6. TELEGRAPH ADDRESS "SIVAD, LONDON". HASLER TELEGRAPH WORKS ERNEST E.{Mr Elliott - Chief Engineer} LLOYD. F.{Mr Friese} MASON. 26, VICTORIA STREET, WESTMINSTER. /86004 WST Wst from AC 2/5/34 Messrs. Rolls-Royce Ltd., DERBY. London, S.W.1. April 27th, 1934. For attention of Mr. Johnson Equipments Engineer. Dear Sirs, Referring to our Mr. W. H.{Arthur M. Hanbury - Head Complaints} Spencer's visit to your Works on Tuesday last, when we tested and adjusted on your synchronous motor two of your Hasler Revolution Indicators to read exactly the known revolutions per minute of the test spindle and tested two new "A" type and two "B" type instruments from our stock, we have to-day taken these four instruments to the Aircraft Inspection Department at Kidbrooke and tested them on their stroboscope. This test proved that the four instruments were all adjusted exactly the same but were reading .25% low, that is to say minus three revolutions at 1200 r.p.m., which confirms the test made at your Works. We discussed with Mr. Sloley, Test Engineer at the Aircraft Inspection Department, your method of testing these instruments on a synchronous motor and he informed us that they have recently been investigating this method of test and have found that whilst it could be depended upon when the load on the power station was constant, it was not safe to make these tests during the mid-day interval when the load, particularly in an industrial town, was suddenly reduced between the hours of 12 and 1 and again rapidly increased between 1.30 and 2.30. It was observed during tests by means of a Neon lamp controlled by a vibrating tuning fork and a revolving slotted cylinder that the action of the automatic frequency regulator could be distinctly seen coming into operation. When the load was shut down the frequency would increase, fall back below normal and then slowly return to normal. The same | ||