Lakeshore Learning Materials 622 - Manual (Page 8)

Lake Shore Model 620/622/623/647 Magnet Power Supply User’s Manual
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Identification of Electrostatic Discharge Sensitive Components
Below are various industry symbols used to label components as ESDS:
HANDLING ELECTROSTATIC DISCHARGE SENSITIVE COMPONENTS
Observe all precautions necessary to prevent damage to ESDS components before attempting installation.
Bring the device and everything that contacts it to ground potential by providing a conductive surface and
discharge paths. As a minimum, observe these precautions:
1. De-energize or disconnect all power and signal sources and loads used with unit.
2. Place unit on a grounded conductive work surface.
3. Ground technician through a conductive wrist strap (or other device) using 1 M
Ω series resistor to protect
operator.
4. Ground any tools, such as soldering equipment, that will contact unit. Contact with operator's hands
provides a sufficient ground for tools that are otherwise electrically isolated.
5. Place ESDS devices and assemblies removed from a unit on a conductive work surface or in a conductive
container. An operator inserting or removing a device or assembly from a container must maintain contact
with a conductive portion of the container. Use only plastic bags approved for storage of ESD material.
6. Do not handle ESDS devices unnecessarily or remove them from their packages until actually used or
tested.
SAFE HANDLING OF LIQUID CRYOGENS
Two essential safety aspects of handling LHe are adequate ventilation and eye and skin protection. Although
helium gas is non-toxic, it is dangerous because it replaces air in a normal breathing atmosphere. Liquid
helium is an even greater threat because a small amount of liquid evaporates to create a large amount of gas.
Store and operate cryogenic dewars in open, well-ventilated areas.
WARNING
•
Liquid helium is a potential asphyxiant and can cause rapid suffocation without warning. Store
and use in an adequately ventilated area. DO NOT vent the container in confined spaces. DO NOT
enter confined spaces where gas may be present unless area is well-ventilated. If inhaled, remove
to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get
medical attention.
• Liquid helium can cause severe frostbite to exposed body parts. DO NOT touch frosted pipes or
valves. For frostbite, consult a physician immediately. If a physician is unavailable, warm the
affected parts with water that is near body temperature.
MAGNET QUENCHES
For protection during a magnet quench, fit the dewar with pressure relief valves of sufficient size and pressure
rating to allow the helium gas to escape and to prevent excessive pressure in the dewar. Operating a magnet
in a dewar without proper pressure relief is dangerous and possibly life-threatening. The magnet may transfer
tremendous energy to the cryogen during a quench. Consult both the magnet and dewar manufacturers to
check pressure relief valve sufficiency.
DANGEROUS VOLTAGES
High voltages are present inside the MPS. Never attempt to service the MPS. Refer all service to qualified
personnel. There are no user-serviceable parts inside the MPS.
The MPS current output terminals may be dangerous. Although MPS output voltage is limited to ±40 VDC, a
catastrophic failure inside the MPS could pass lethal voltages to the output terminals. Do not touch the
terminals during MPS operation.