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THE IGNITER is energized through the 115 V.AC control circuit when the LAMP
"ON-OFF" switch (S2) is depressed and all interlocks and air flow switches are closed.
CAUTION: Do not use the Emergency Ignition switch (S102) in the igniter until it is
determined that the polarity of the xenon bulb is correct. Use of the S102 switch bypasses the polarity
sensing diode (CR201) on the igniter printed circuit board; if polarity is not correct, the bulb will be
seriously damaged or destroyed. No credit is allowed on bulbs damaged by reversed polarity.
THE IGNITER supplies a high RF voltage pulse to the bulb, together with the high
"No Load" DC voltage from the xenon power supply, to ignite the xenon bulb. After the arc is
sustained, the AC circuit in the igniter is interrupted by the opening of K201 relay contacts on the
signal of the timer circuit on the PC board. The DC output of the xenon power supply is automatically
lowered to the power level required to maintain the arc. The DC power to the bulb is dependent upon
the bulb characteristics and the setting of the output of the xenon power supply.
DC VOLTAGE is applied to the printed circuit board from the xenon power supply,
energizing the 12 V.DC coil and closing the contacts of K201 relay, completing the AC circuit through
the igniter to the T102 high voltage (10 kV.) transformer. High voltage boost capacitor C107 is
charged to a voltage sufficient to cause breakdown across the E101 spark gap. Approximately 35 kV.
is supplied to the xenon bulb for ignition.
S101 is the igniter cover interlock switch and S102 is the Emergency Ignition switch,
which is a bypass for the K201 relay contacts and CR201 polarity sensing diode on the PC board.
Components C101, 102, and 103 function as RF bypass capacitors on the igniter. The C108 capacitor
serves as a coupling capacitor to the current coil.
THE PC BOARD operates on DC voltage from the xenon power supply. Capacitor
C201 across the positive #10 and negative #15 is an RF suppression capacitor. Resistor R201 and
zener diodes VR201 and 202 drop the DC voltage to 12 volts for the K201 relay coil. CR201 is the
polarity sensing diode. C204 is a polarized capacitor used for arc suppression at the K201 relay coil,
and CR202 functions as a transient protection diode.
THE FOLLOWING COMPONENTS are parts of the timing circuit on the PC board:
Timer chip U201, resistors R202, 203, and the polarized capacitor C203. The C203 capacitor func-
tions as the timing control, and CR203 serves as the "ON" time control diode. C202 is the control
voltage isolation capacitor.
PRINCIPLE OF IGNITER OPERATION
U80/017
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