RVR Solar VJ1000, User Manual, Page: 14 / 86

VJ1000
10 / 40 USER MANUAL Rev. 3.0 - 26/02/01
5. Electrical Description
5.1 Introduction
This section describes in detail, the operation of the VJ1000.
For ease of description, the unit has been divided into sections, each of which is described in
detail, below.
5.2 Power Supply
The power supply, accessible via the rear panel, has been designed to be both rugged
and at the same time simple to maintain, allowing easy access to every component thus
easing repair work.
The power supply features a PI filter after the rectifying stage which attenuates spurious
components.
Two fuses provide overload protection.
The power supply comprises two separate transformers: the largest supplies the tube anode,
the other transformer supplies the tube's filament and supplies various functions such as
relays and the protection system.
This power supply is designed to work at single phase voltages.
5.3 Protection Card
This card is mounted in a metal box and fixed to the right-hand side of the RF chamber’s
chassis (6 Photo 2). This sub-unit has three alarm inputs which carry the signal to a comparator
which compares them to a pre-defined threshold. Should one of these inputs exceed the
alarm threshold, the amplifier is disactivated and a counter is started.
If the fault condition does not dissappear within the period defined by the counter, the unit is
shut down indefinately.
5.4 Tube
The ceramic/metal power triode 3CX800A7 has been designed to work in AB
2
class
amplifiers, in class B cathode-driven amplifiers, in audio or RF applications including the
VHF band, or in class C cathode-driven, anode-modulated RF amplifiers.
As linear amplifiers, they feature high power gain with low levels of intermodulation.
For the tube specification, see table C.
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