KA BAND OUTDOOR TWT AMPLIFIER
f)
Do not assume that the level of risk is a function of size.
Some large high power
voltage equipment looks docile. One reason the equipment is so big is to get the
proper separation between high voltage points. On the other hand, just because the
equipment is small is no assurance of safety. Dense packaging results in more difficult
access and increases the chance that you will accidentally hit the wrong point.
g)
Always discharge high voltage capacitors.
High voltage capacitors store a lot of
energy for long periods of time. High voltage capacitors also exhibit a "memory" in that
they can recover after discharge and reach lethal levels. In addition to the "memory"
problem, there have been instances where the built-in safety features have failed or
have been miswired.
Each and every time you go to work on a piece of high voltage
equipment, use a discharge device with a long handle to discharge every high
voltage capacitor.
h)
Do not depend on the automatic features of the equipment to save you.
You never
know when someone has left a circuit disabled, if there has been a wiring error, or if a
component has failed.
i)
Take personal responsibility to assure that no one can turn on the high voltage
circuits when you are working on the equipment.
Precautions would include taping
down (or installing a keeper) on controls/circuit breakers and/or disconnecting the
power source to the high voltage circuits, activating interlocks that prevent high
voltage turn on, etc. Know where the disconnects are and use them. Do NOT rely on
anyone not to turn on the high voltage.
j)
Set up your test equipment with the power off.
Conduct the power-on operations
when you have your hands out of the equipment.
k)
Do not use short probes for high voltage measurements.
A short probe does not allow
any margin for error. If your hand slips you could accidentally come into contact with
a danger point. A long probe avoids the whole problem.
l)
Read the instruction manual.
The best insurance is foreknowledge of hazards.
m)
Create a favorable environment for safe operations.
This means that if people are
crowding you, stop the operation if it involves high voltage. Pressure can lead to
carelessness. In the same way, fatigue is also an enemy. STAY ALERT AT ALL TIMES
WHEN WORKING WITH HIGH VOLTAGE.
n)
Do not become over-confident.
Maintain a healthy respect for high voltage.
o)
A good operating practice is to check the potential between the equipment chassis
and earth ground before you complete the circuit with your body
. As voltage levels
increase, the protection you get from insulation and air gap diminishes. For example, in
a piece of equipment that involves beam voltages of about 16kV, the beam transformers
look very safe with massive insulation on the outside of the coils. Physical contact with
the beam coil when the system is operating can be fatal. Although the equipment is
placard to warn people of the presence of high voltage, it is virtually impossible to
placard every point of danger in a system.
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