Telemark TT Cheetah Series Power Supply Instruction Manual
25
SOURCE
HVAC
Lit when HVAC interlock is closed
SOURCE
H20
Lit when H20 interlock is closed
SOURCE
AUX2
Lit when AUX2 interlock is closed
Operation
Initial Start-Up
When all connections have been made as described on pages 15 and 16 the power supply is
ready to use.
Make sure that the Control Power switch on the controller is off (down), the Control Select
toggle switch is in center position (Local) and both Voltage and Emission potentiometers are
all the way down at 0 (zero).
Turn on the main breakers (Control & High Voltage) on the front panel of the HVPS, the
green power LED (PWR) on the controller will come on.
Turn on the Control Power switch on the controller, the green interlock LEDs (if interlocks are
satisfied) and the two LCD meters will come on.
With all interlocks satisfied, both yellow OFF push buttons for HV and Source will be lit which
indicates "ready". It may take a few moments before proper air flow to the tube is established
and the AIR/CAB interlock is satisfied.
For the TT-3 and TT-6 the time delay will now start, indicated by a blinking AIR/CAB LED, the
HV OFF button still not being illuminated (HV not ready).
The TT-3 and TT-6 design is based on indirectly heated oxide cathode tetrode tubes which
require a few minutes of heat-up for adequate electron generation. A built-in time delay circuit
(~ 3 minutes) disables HV during the heat-up time of the tube.
The TT-8/10/15/20 with their directly heated power beam tetrode tubes do not require any
heat-up time, and HV becomes ready as soon as the AIR/CAB interlock is satisfied.
When HV is ready (yellow OFF push button illuminated), HV can be turned on by pressing the
green ON push button. This will be light up instantly, indicating that HV is on.
Slowly dial up the Voltage potentiometer, watching the DC Output Voltage LCD meter. Keep
increasing HV up to maximum voltage, paying attention to any arcing that may occur in the
vacuum chamber (instability of HV reading, flashing of ARC LED).
When HV is stable at maximum kV, leave potentiometer in this position, or set to desired HV
level, depending on e-beam source type and application.
Turn off HV.
Set the Display Select toggle switch next to the Source LCD meter to Filament (down).
Turn on Source by pressing the green ON push button, this will light up instantly, indicating
that power is supplied to the filament. After a few seconds of source filament heat-up, the
Source meter will read a bias (preheat) filament current of around 18A.
A good range for setting the bias for Telemark sources is some 17 to 20A, settings for other
sources need to be determined by trial (yellow glow of the filament, but still a few amps below
emission point, see next step below) but should be very similar.
Flip Display Select toggle switch to Emission (up), turn ON HV, then slowly turn up the
Emission potentiometer, watching the Source meter (reads mA in the Emission mode). Check
for correct position of the beam in the pocket, and bring up emission further to heat the
material to evaporation point.
This completes the initial test of the power supply.
Turn down the Emission potentiometer to zero and turn off Source and HV.
Allow a few moments of cool-down for the tube before turning off Controller Power and the
main breakers of the HVPS.