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A cell-testing voltmeter and hydrometers to be provided together with all the necessary insulators, connectors, separators, spray arresters and general accessories.
Concentrated acid only to be supplied with the battery.
The plates to be burnt on to the connecting lugs, which are arranged to be bolted together to furnish the requisite connection between cells.
The stands to be made of the best pitch pine, painted with three coats of hot linseed oil and put together without metal fastenings of any description.
TRANSFORMER.
16. To be of the single-phase closed iron circuit core type contained in an oil tight galvanised iron case completely filled with high flash insulating oil for cooling purposes. The transformer to be capable of delivering 5 KVA. at either 7,000 or 14,000 volts when supplied with alternating current at 500 volts and 300 cycles. The secondary to be divided into two halves, the ends of the windings being brought to high tension terminals mounted on the containing case; suitable connecting links to be supplied to enable the secondary windings to be readily connected either in parallel or series.
In conjunction with the transformer suitable air-cooled air-core adjustable low frequency inductances, fitted with series-parallel links, to be furnished to enable the circuit to be brought into reson- ance with the high frequency oscillation circuit. Suitable air-core protecting chokes to be inserted in the leads from the transformer to the high frequency circuit to protect the windings of the trans- former from damage by high frequency surges.
CONDENSER BATTERY.
17. To consist of a bank of 8 units of the self-insulating glazed ironstone container type with oil-sealed lids and high-tension terminals. Each cell to be filled with special high flash point insulat- ing oil. The units of the bank to be suitably grouped to afford that capacity which, in conjunction with the variable inductance of the high frequency primary circuit, will give the required range of wave lengths in transmission. The arrangement of the condensers to be also such as to ensure the absorption of the total amount of energy to be supplied by the transformer circuit without bringing any undue electrical strain on the individual condenser cells and with the minimum heat losses. The battery to be provided with a set of busbar connectors and insulating separators for connecting up the condenser battery to other parts of the high frequency primary circuit.
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DISCHARGER.
18. To be of a special type designed to produce a musical note in transmission and to be mounted on an extension of the motor alternator shaft. To consist generally of an insulated disc carrying a number of studs bearing a direct numerical relation to the number of poles in the alternator, rotated between stationary adjustable copper electrodes. The electrodes to be provided with means of adjustment to afford a control over the time at which the discharge takes place, and to ensure the correct relationship between the alternator voltage phase and the moment of discharge. The design of the disc to be such as to afford a spark frequency of 600 per second when running at the normal speed and in correct phase relation to the alternator as described above.
TRANSMITTING JIGGER.
19. The jigger to be of the independent primary and secondary circuit type, having a 5-turn primary made up of independently insulated copper conductors laid-up so as to provide for equal distribution of current throughout and a multiple turn secondary of similar cable suitably spaced. The primary to be provided with terminals and an adjustable plug connection to afford a means of rapidly changing the number of turns of the primary included in the circuit, and the secondary to be provided with suitable plug sockets for connection at various points with the aerial tuning inductance. The primary and secondary to be enclosed in separate cases and the secondary to be arranged to slide laterally with respect to the primary for the purpose of varying the coupling between the circuits.
AERIAL TUNING INDUCTANCE.
20. The aerial tuning inductance to consist of a solenoid winding of cable similar to that of the jigger secondary, having a total inductance sufficient for tuning the aerial circuit over the full range of transmitted wave lengths specified above. The inductance to be provided with insulated plug sockets to enable it to be connected to the jigger secondary and the aerial respectively.
MANIPULATING GEAR.
21. To consist of a Morse hand key actuating a continuous current electro-magnetic relay key in the transformer primary circuit. A pair of subsidiary contacts on the hand key to be provided to ensure the short-circuiting of the telephone circuit of the receiver when the key is depressed, thus preventing the hearing of the
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