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).
Product description for the new MEG Insulation Tester by Evershed & Vignoles Limited.
| Identifier | ExFiles\Box 165\3\ img038 | |
| Date | 1st October 1922 guessed | |
| 4 EVERSHED & VIGNOLES, LIMITED. A new set of revolutionary design Our new product, the MEG Insulation Tester combines these features. The name, a kind of diminutive of "Megger," has been given to it to suggest its relationship to the Megger Testing Set. The new set is designed by engineers and will appeal to engineers. It is robust, being contained in a metal case which will withstand considerable rough handling, and is impervious to weather. It is far lighter than anything of the kind yet produced, weighing less than 7 lbs.; it is smaller than anything which has gone before, the dimensions being only 5 3/4" x 7 3/4" x 6 1/4"; it is efficient, capable of carrying out all the customary insulation tests. It is cheap, in consequence of the fact that every refinement which could be dispensed with has been omitted and essentials only retained. Description of the MEG Insulation Tester The new instrument, of which Fig. 1 is a general illustration, is contained in a case of cast aluminium, one end of which is formed of an oil-tight gear box. In this box steel gear of concentric type is entirely enclosed, so that it is kept clean and thoroughly lubricated. The driving handle is always ready for use; and is of such a shape that it is naturally protected by the box and no ordinary blow can damage it. At the same time it does not project in a manner to interfere with the snug packing of the instrument. A free-wheel device protects the gear from damage, and prevents the armature from being turned the wrong way. At the further end from the handle an element of the case contains the ohmmeter and protects the "LINE" and "EARTH" terminals, which are housed conveniently beneath it. At the top a glass window with hinged cover gives a view of the dial, which is clearly marked with the scale of readings. The carrying handles are of ingenious construction, they hang at the side of the case entirely out of the way when the MEG is in use, and meet together in a flat spring catch, which lies comfortably in the hand, when the instrument is carried. In Fig. 2 we illustrate the instrument with the handles folded back and the dial cover opened, ready for use. This beautiful and substantial construction (Registered Design No. 690329) has been rendered possible by our system of guarded circuits, and by the introduction of a number of other novel patented features in both generator and ohmmeter. The reduction in weight compared with all that has gone before has not been obtained at the expense of working forces, for these are large in proportion to the mass and inertia of the movement, giving great promptness and precision in the indications. Our patented spring jewels are employed for the movement and give security against damage by careless usage. One of our main objects being to secure the lowest possible selling price, it becomes important to manufacture on the largest possible scale. For this reason we have decided for the present to make the MEG Insulation Tester in one form only, provided with a variable pressure generator developing 500 volts at 100 r.p.m. and ACTON LANE WORKS, CHISWICK. 5 Registered Design | ||