Telemark TT-10, Instruction Manual

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18
BIAS ON/OFF SWITCH - With bias on, adjust bias trimpot for
minimum beam. Primarily used to position beam and sweep
pattern, before beginning operation.
19
BIAS - The Bias adjustment is located at the center of the
Source Control group. The Bias potentiometer is recessed.
The resistor is used to adjust the “bias” set point (the minimum
source current). Turning counter-clockwise with a small flat
head screwdriver increases the filament current. With the
source current on and the emission current set at “0" the bias
should be adjusted to the point that the beam just begins to
appear. Line voltage changes may affect this setting.
2
0
SOURCE CURRENT DISPLAY - Source current is displayed by
the digital meter at the top of the Source control group.
21
EMISSION CURRENT ADJUST - The Emission Current
potentiometer is located at the right center of the Source
control group and is used to set the desired value of source
current. Adjustment between the bias setting level and the
current limit can be made. Special circuitry protects the power
supply, and may cause interruption of the power supply at a
setting exceeding the maximum rated current (1 Amp for TT-10,
1.5 Amp for TT-15) cutback.
The state of all Source interlocks is continuously checked. If any condition is not
correct, the corresponding indicator will not be lit. The Source Group Indicator
Lights are (left to right):
2
2
HIGH VACUUM - With a high vacuum gauge utilized in the
system, the minimum vacuum level set on the gauge must be
present before the source can be energized.
2
3
WATER - A water flow switch on the water return line from the
source assures that there is sufficient water flow to cool the
source.
24
AUXILIARY 2 EXTERNAL INTERLOCKS - This interlock is used
for additional interlocks that may require the source be turned
off, such as an interlock that prevents emission while the
crucible rotates.
HV/Power Cabinet
See Fig. 4-B
25
POWER RESET - The front panel of the HV/Power Cabinet
contains circuit breakers. They protect the power supply from
4-4
CONTROLS AND INDICATORS
Telemark TT-10/15 Power Supplies