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).
Instruction and specification sheet for Vertical Electrostatic Voltmeters and Portable Volt Balances.
| Identifier | ExFiles\Box 53\1\ Scan167 | |
| Date | 16th June 1924 guessed | |
| KELVIN BOTTOMLEY & BAIRD LTD. (KBB) GLASGOW & LONDON List No. | Ranges obtained in Volts. | PRICE. | CODE WORD. 1128 | 500 – 2,000, 1,000 – 4,000, 2,000 – 8,000 | £21 0 0 | Debar 1129 | 500 – 3,000, 1,000 – 6,000, 2,000 – 12,000 | £21 0 0 | Debase 1130 | 1,000 – 5,000, 2,000 – 10,000, 4,000 – 20,000 | £31 10 0 | Debate See note regarding safe maximums on alternating current (p. 1). INSTRUCTIONS FOR USING THE VERTICAL ELECTROSTATIC VOLTMETER. 1. The stop pins supporting the moving vane should be unscrewed and the vane allowed to rest on the knife edges, afterwards replacing the stop pins. 2. To detect, and if necessary correct, any accidental bending of the pointer, hang one of the weights on the knife edge at the lower end of the movable vane. Take the round pin fitted in weight box, and with it press the movable plate between the two fixed plates, until the pin rests in the two V notches at upper end of fixed plates; holding the pin so, rotate it about its axis, and observe that the pointer indicates a small red line on the scale. 3. The moving vane of instrument when sent out is in neutral equilibrium, but if by any accident its balance be upset, it can be adjusted by means of the two screws at the lower end of the movable vane. This adjustment is, however, an extremely delicate operation, and must be performed with great care. 4. On no account whatever should the screws at the lower end of the movable vane be moved unless for the reason given above (clause 3). 5. After hanging on the weights, adjust the pointer to zero by means of the screw levelling feet of the instrument. 6. In order to check the oscillation of the movable vane, a rod is provided which can be brought to bear on the pointer. Electrostatic Volt Balances are intended to measure higher voltages than those covered by the Vertical Electrostatic Voltmeters. The Volt Balances essentially consist of an insulated metal plate or “bun,” which when charged attracts another metal plate or pan attached to a movable arm, which in turn travels over a graduated scale. This instrument is made in two sizes, one being supplied in a portable form, and is intended more particularly for pressure testing of cables. The larger instrument is intended for use in a test room of a cable factory, or for experimental purposes. Most of the larger Cable Companies, as well as Technical Colleges, have been supplied with these instruments. KELVIN BOTTOMLEY & BAIRD LTD. (KBB) GLASGOW & LONDON The portable instrument, No. 1133, is fitted in a case of insulating material, and is supplied complete with polished wood box supported on porcelain insulators, so that the instrument can be used inside this box. Only one range is obtained on this instrument. Electrostatic Volt Balance, No. 1133. Electrostatic Volt Balance, No. 1134. In the larger instrument, No. 1134, two distinct ranges are obtainable by hanging different weights on the scale pan. In both instruments an efficient magnetic damper is provided, rendering the action dead beat. The ranges given below are safe on alternating current circuits when the conditions are such that the curve approximates a sine wave. List No. | Ranges in Volts. | PRICE. | CODE WORD. 1133 | 5,000 – 30,000 | £60 0 0 | Debit 1134 | 5,000 – 30,000, 20,000 – 100,000 | £110 0 0 | Debtor INSTRUCTIONS FOR USING THE PORTABLE VOLT BALANCE. 1. The instrument should be withdrawn from the wood case, and the pointer and scale pan (which are attached to separate carriers) fitted to the instrument. 2. Connection is then made to the terminal at the bottom of the instrument and the terminal on the case, and the instrument replaced in wood box. 3. The instrument should be levelled according to the indications of the level attached, and until the pointer of the instrument reads zero. Instructions for setting up and adjusting the larger size Balance are sent with each instrument. | ||