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 and brochure for Marconi-Ekco noise and vibration measurement equipment.
| Identifier | ExFiles\Box 138\1\ scan0309 | |
| Date | 1st April 1938 | |
| SPECIFICATION. NOISE METER. Type TF{T. Fisher}500. Range: 40-120 phons. This corresponds with a range of 40 to 120 dB{Donald Bastow - Suspensions} when referred to a reference level of 0.0002 dyne per sq. cm. at 1,000 c.p.s. Accuracy: ± 2 phons on steady sounds. ± 4 phons on impulsive sounds. Frequency Characteristic: Three alternative adjustments are provided :— (a) Flat. (b) 40 dB{Donald Bastow - Suspensions} equal loudness contour. (c) 70 dB{Donald Bastow - Suspensions} " " " Microphone: Piezo-electric non-directional type having an exceptionally wide frequency response. Meter: The indicator system agrees approximately with the ear in regard to the rapidity of response. Amplifier Gain: An input signal of about 20 µV applied to the microphone socket will produce half scale deflection on the output meter at the 50 phon setting. Batteries: Unspillable 2-volt accumulator and 90-volt dry battery. Calibration: Means are provided for restandardising the calibration at power supply frequencies. Mounting: The controls and meter are conveniently disposed on a vertical aluminium panel which is mounted in a welded aluminium case having a removable lid{A. J. Lidsey} and carrying handle. Finish: Panel—Black crackle lacquer. Case—Grey cellulose enamel. Dimensions: 14" × 13½" × 7¼" (over projections). 20" × 19" × 15" (approx.) packed. Weight: 23 lbs. nett. 61 lbs. gross (approx.) packed. Price: See Price Index. VIBRATION PICK-UP. Type TF{T. Fisher}481. Frequency Range: 10 to 3,000 c.p.s. Frequency Characteristic: For constant amplitude, the voltage output is roughly proportional to the square of the frequency up to 3,000 c.p.s. which is the natural frequency of the unit. Proportionality: At any one frequency the output is directly proportional to the amplitude of vibration up to an output voltage of one volt. Sensitivity: At 250 c.p.s the output is approximately 0.25 volt per 0.001 inch of motion. Probe: Duralumin prod 8½" long with hardened steel tip. The tip may be removed and screwed directly into the unit. Connections: 8 feet of screened cable, terminated in a plug for connection to the Noise Meter. Dimensions: 3" diameter × 1½" deep. Weight: 4 ounces; with prod 8 ounces. ADJUSTABLE TUNING UNIT. Type TF{T. Fisher}456. See leaflet COM.-D-7. SPECIAL MODELS. A special high sensitivity Noise Meter, Type TF{T. Fisher}397 is available without the impulse feature. The range is 24 to 130 phons and an input signal of 3 µV applied to the microphone socket produces half scale deflection on the output meter at the 30 phon setting. This sensitivity can be increased still further by means of a directional microphone—the range then being 18-124 phons. A mains operated Noise Meter is available, also Tuning Units with special frequency ranges and detachable cover. MARCONI - EKCO INSTRUMENTS LTD. ELECTRA HOUSE VICTORIA EMBANKMENT LONDON, W. C. 2 Telephone: TEMple Bar 4321 MARCONI-EKCO INSTRUMENTS LTD. ELECTRA HOUSE, VICTORIA EMBANKMENT, LONDON, W. C. 2, ENGLAND. NOISE! NOISE METERS, TYPE TF{T. Fisher}500 AND TF{T. Fisher}397 AND ACCESSORIES. Illustrations show the Noise Meter, Type TF{T. Fisher}500 (above) and as part of an assembly with the Adjustable Tuning Unit, Type TF{T. Fisher}456 and the Vibration Pick-up Unit, Type TF{T. Fisher}481 (overleaf). The instruments of this series provide a complete and flexible system for the measurement and comparison of noise and vibration. The study of these quantities is becoming of increasing importance particularly in relation to industrial and social psychology. The abatement of noise has definite beneficial effects on the health of individuals and on their efficiency, and the quantitative evaluation of noise is therefore of growing interest not only in factories and offices but to public authorities and such bodies as transport organisations. An outline of the performance and some examples of the applications of the instruments of this series are given overleaf. The Noise Meter is self-contained, and portable, and is direct reading in phons. Certain features—notably the type of rectifier circuit used—are based on the description of an instrument in a paper by Dr. A.{Mr Adams} H.{Arthur M. Hanbury - Head Complaints} Davies of the National Physical Laboratory. Particular care has been taken in the design to ensure an accurate indication of transient noises. The auxiliary apparatus available includes a piezo-electric vibration Pick-up which replaces the microphone when mechanical vibration is to be measured. For special purposes an Adjustable Tuning Unit is available by means of which noise of a particular frequency can be emphasised or suppressed. For individual harmonic analysis we recommend our Harmonic Analyser, Type TF{T. Fisher}455. | ||