Keithley 2657A, Reference Manual, Page: 31 / 805

Model 2657A High Power System SourceMeter® Instrument Reference Manual Section 2: General operation
2657A-901-01 Rev. B/December 2012 2-7
Cooling vents
The Model 2657A has top and side intake vents and a rear exhaust vent. The rear exhaust vent and
either the top or both side intake vents must be unobstructed to properly dissipate heat.
Excessive heat could damage the Model 2657A and degrade its performance. Only operate the
Model 2657A in an environment where the ambient temperature does not exceed 50 °C (122 °F).
Do not place a container of liquid (water or coffee, for instance) on the top cover. If it spills, the liquid
may enter the case through the vents and cause severe damage.
To prevent damaging heat build-up and ensure specified performance, use the following guidelines.
The rear exhaust vent and either the top or both side intake vents must be unobstructed to properly
dissipate heat. Even partial blockage could impair proper cooling.
DO NOT position any devices adjacent to the Model 2657A that force air (heated or unheated) toward
its cooling vents or surfaces. This additional airflow could compromise accuracy.
When rack mounting the Model 2657A, make sure there is adequate airflow around both sides to
ensure proper cooling. Adequate airflow enables air temperatures within approximately one inch of
the Model 2657A surfaces to remain within specified limits under all operating conditions.
Rack mounting high power dissipation equipment adjacent to the Model 2657A could cause
excessive heating to occur. To produce specified Model 2657A accuracies, maintain the specified
ambient temperature around the surfaces of the Model 2657A. Proper cooling practice, in rack
configurations with convection cooling only, places the hottest non-precision equipment (for example,
the power supply) at the top of the rack away from and above precision equipment (such as the
Model 2657A).
Mount precision equipment as low as possible in the rack, where temperatures are coolest. Adding
space panels above and below the Model 2657A will help provide adequate airflow.
Turning your instrument on and off
The following topics describe how to power your instrument on and off, place the instrument in
standby, configure the line frequency, and replace the line fuse.
Procedure
The Model 2657A operates from a line voltage of 100 V to 240 V at a frequency of 50 Hz or 60 Hz. At
the factory, each Model 2657A is configured to match the power line frequency appropriate for your
country (either 50 Hz or 60 Hz). Make sure the operating voltage in your area is compatible.
Follow the procedure below to connect the Model 2657A to line power and turn on the instrument.
CAUTION