which is proportional to regulator Zener current, exceed
+6.8 volts, Zener diode CR270 will conduct, the base of
contains fuses and time-delay relays for circuit
transistor Q204 will be driven positive, transistor Q204
will conduct, and its collector will go nearly to 0 volt
(1) Three indicating fuses, 01, 01, F202, and
Base current for transistor Q205 can no longer flow
through resistor R238, transistor Q205 will cut off, and
power operation. For half-power operation, dropping
the contact of relay K201 will open.
resistors are inserted in series with the primary power,
f. High-Voltage Power Supply Circuit (Fig.
bypassing the fuses. The high-voltage circuit is protected
7-5). The high-voltage power supply circuit consist of
(2) Relay K206 is a -minute time-delay device
high voltage transformer T201 and a conventional three-
operating on phase C of the ac line, and allows sufficient
phase bridge rectifier E201.
cathode warm up time for magntron V201. Since the
filament power for magntron V201 is derived from the
connected) receives its power from a 120-volt 3- phase,
system +28-volt supply, relay K205 must be operated by
400-Hz source through the closed contacts of relay
28 vdc to sirt the time-day cycle. Relay K206 supplies the
K201. The stepped-up voltage developed across the
solenoid voltage for HV ON relay K201 (fig. 2-).
secondary windings of transformer T201 is rectified by
his ensures preheat for both the magnetron and
bridge rectifier E201 to an unregulated output of
thyratron. Relay K207 is a time-delay holding relay and
approximately +4500 volts. The negative end of the
removes power from relay K206 after the time delay. If
rectifier is returned to ground through bleeder resistors
for any reason the 28-vdc supply is interrupted, relay
R226 and R227 for narrow-pulse operation, and
K207 will restore and the time cycle must be repeated.
through resistor R227, diode CR265, and the closed
contacts of relay K204 for wide-pulse operation. The
difference is necessary because of the difference in
Rf Section Description
average current and the requirements for a different
overload sensor tripping current.
a. General. The rf section consists of a ferrite
Figure 2-6. Overload sensor circuit, simplified schematic