CPI 0102324500rR Manual page 13

l. A good operating practice is to check the potential between the equipment chassis and
the earth ground. As voltage levels increase, the protection from insulation and air gap
diminishes. For example, in a piece of equipment that involves beam voltages of about
16kV, the beam transformers appear 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 has warnings of the presence of high voltage, it is virtually impossible to pin
point every danger in a system.
m. If an operator is not trained on the function and hazards associated with the equipment,
they should not handle the equipment. The greatest protection, when dealing with high
voltage equipment, is detailed knowledge of that equipment.
n. Avoid unorganized equipment setups. Take the time to make sure equipment setups are
organized to allow proper operation and maintenance to occur.
o. Make sure all high voltage and ground connections are secure. Fasten leads using all the
hardware provided. The only safe connection is a mechanically secure one.
p. Watch out for exposed high voltage leads. Some connectors depend on circuit loading to
avoid arcing between closely spaced terminals. Loaded high voltage lines or plugs can lead
to arcing.
q. Shut off the high voltage when performing a low voltage measurement. It does not make
sense to increase the danger of being shocked needlessly. There are times when high
voltage cannot be shut off during a low voltage measurement. Most of the time this is not
the case.
r. Remove test equipment when finishing a measurement program. Many instruments have
been destroyed or damaged because a test program was conducted in a haphazard manner,
rather than in an orderly progression from start to finish. Tragedy can be avoided by
applying an order to the operator's method.
s. Be cautious when making filament voltage measurements. The cathode of the tube is
elevated above (or below) ground and the filament voltage usually cannot be measured
with reference to ground. Assure the high voltage cannot be turned on when making
measurements. This includes disconnecting the high voltage drive source, locking breakers,
shorting out appropriate leads, enabling interlocks, and anything else to prevent accidental
injury.
t. When troubleshooting, assume switches are defective. A high voltage switch may be shut
off, but if the switch were defective, the high voltage would still be on. Units have the
potential to shock or kill if a switch has failed.
u. Make sure that workstations are sturdy.
equipment present a real threat to the operator. DO NOT use a setup that is known to be
unstable and/or dangerous.
v. Use a 5-minute rule. Wait at least 5 minutes after shutting off equipment before working on
it. The 5-minute rule pertains to the dielectrics or insulators used in high voltage circuits
that can store a charge. While the amount of charge stored is a function of the size of the
dielectric, a 5-minute rule provides an adequate margin for safety.
D .01023245 R .R
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