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Sensibly equivalent to:
CV92 CV1256 NT99 W2514
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The W5534 is a radar power assembly with two W2514 Admiralty pattern micropup triodes connected in parallel. The W2514 is also known as the NT99.
The NT99 is a radar power triode or and was designed for 50 cm operation and with a maximum anode dissipation of 150 Watts. This Type was the most widely used of the micropup pulsed triodes.
The NT99 was used in the AMES11 600 MHz mobile ground radar used by the RAF. Fire control radar type 284 operating at 600 MHz and used by the Navy HMS Hood was fitted with the 284 as were other ships that tracked the Bismark. For the 1941 Type 291 radar the modulator was the CV22. It was also used in the AI radar at 200 MHz.
For radars like the 284 the W5534 assembly was the main RF power valve. At 600 MHz the parallel pair produced some 20 kW per pulse.
The construction is co-axial and the anode is finned to enable forced air cooling. The grid is connected via a depression in the envelope.
The CV199 is a low emission valve and the full emission version is the CV1256 (NT99).
The anodes are held together with this two part bridge. It is silver plated inside and out. The inner surface is brightly polished.
One NT99 with the grid joiner still in place. Air is forced down the tube and exits at the grid glass/metal seal. The ribbed parts are flexible couplers.
One grid connector. The stud on the valve screws into the silver plated nozzle. The holes and circumferential slots allow the air to cool the grid connection.
The nozzle in close-up.
The grid bar screwed into the re-entrant envelope.
One of the micropup triodes. The central connection is for the cathode/heater and the other wire is the heater return.
The identification of W2514 on the anode heat sink.
The heat sink discs fit onto the external anode. The anode cylinder is silver plated.
The grid connection. The grid itself can just be seen as a series of bright points. The construction is a squirrel cage or cylindrical arrangement of wires between two end supports. The heat sink fins can be seen to be separate from the anode and appear to be soldered in place.
The two valves connected via the grid tube.
The complete W5534 power tube assembly.
Diagram of the NT99 in section.
The valve glass is 33 mm in diameter, and overall, is 225 mm tall.
References: Data-sheet, 1005 & 3002. Type W5534 was first introduced in 1940. See also 1940 adverts.


Absolute Maximum Operating Conditions
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated December21, 2019.
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