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).
Specification sheet for a miniature current transformer and ammeter portable testing outfit.
| Identifier | ExFiles\Box 168\5\ img290 | |
| Date | 1st April 1934 | |
| SECTION G.{Mr Griffiths - Chief Accountant / Mr Gnapp} MEASURING INSTRUMENTS. SHEET G 39. MINIATURE CURRENT TRANSFORMER AND AMMETER. A PORTABLE TESTING OUTFIT FOR USE WITH ALTERNATING CURRENT. (FIRST GRADE ACCURACY TO BRITISH STANDARD SPECIFICATION No. 89) TRANSFORMER. Overall Dimensions. 5" x 3.6" x 1.25" (127 x 92 x 32 mm.) Size of Aperture. 1.375" diameter (35 mm.) Weight. 1 lb. 1 oz. (.482 kg.) Secondary Current. 0.5 ampere. Rated Burden. 2 V.A. with any frequency from 50-150 cycles. Frequency. 20 - 150 cycles. Ranges. 2.5-200 amperes. MOVING IRON AMMETER. Overall Dimensions. 3.75" x 4.2" x 1.625" (95 x 107 x 41 mm.) Length of Scale. 2.375" (60 mm.) Angular Deflection. 100 degrees. Range. 0-5 ampere. Weight. 9 ozs. (.255 kg.) Total Weight of Outfit (excluding leads and transport case)—1 lb. 10 ozs. (.737 kg.) DESCRIPTION. This testing outfit, comprising a Miniature Current Transformer and a Miniature Moving Iron Ammeter, provides a convenient method of measuring alternating current with a degree of accuracy as specified in British Standard Specification No. 89 for "First Grade" moving iron instruments. Ranges are available up to 200 amperes and accurate readings can be obtained down to 50 milliamperes, covering seven ampere ranges in all. Transformer — The transformer has three self-contained primary windings, giving ranges of 2.5, 10 and 25 amperes, respectively. The internal windings are connected to terminals (with non-removable insulated heads) fitted to the case, which is suitably engraved with range particulars. In addition to the ranges obtained with the self-contained primary windings, the range of the transformer can be increased by winding a suitable cable or conductor, a required number of turns, through an aperture provided in the centre of the transformer for this purpose. By this means, ranges can be obtained as follows :- 4 turns : 50 amperes, 2 turns : 100 amperes and 1 turn: 200 amperes. The secondary current is 0-5 ampere, and the rated burden is 2 V.A., with any frequency, from 50 to 150 cycles. The transformer is insulated suitable for use on circuits where the voltage does not exceed 750 volts. Owing to the special nature of the core, the transformer may be used on any frequency from 20-150 cycles. It can also be adjusted for use with a wattmeter to measure watts at 50 cycles, providing the burden of the current element of the wattmeter does not exceed 2 V.A. ELLIOTT BROTHERS (LONDON) LTD SIEMENS BROTHERS & CO LTD 4-34. PRINTED IN ENGLAND. | ||