Gamry Instruments Reference 30k Booster, Operator'S Manual

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Grounds and Floating Operations
49
If the System Ground is connected to the Protective Ground , it compromises a boosted system’s ability to
make measurements in electrochemical cells that contain earth-grounded metal. One prominent example is
electrochemical cells in autoclaves, where the autoclave’s earth-grounded wall is generally used as the counter
electrode of the cell.
Use in Systems Connected to Earth Ground
The Reference 30k Booster can be used to make measurements on systems with one electrode connected to
earth ground. High-temperature cells in an autoclave, water-cooled cells, and systems with AC-powered pumps
may have earthed metal in the cell’s electrolyte.
The System Ground must be isolated from earth ground when you test earth-grounded systems. Disconnect
the ground jumper as described above.
When you use the a Reference 30k Booster in a system with an earth-grounded electrode, the System Ground
will develop a voltage versus earth ground. The magnitude of the voltage depends on which electrode is
earthed and the cell voltage. In all cases, the voltage will be less than 24 volts.
Limits on Ground Voltage
The Reference 3000 contains TVS surge suppressors that limit the voltage difference between the Reference
3000’s chassis ground and the USB ground to about 40 volts. These surge suppressors are not part of the safety
mechanisms in the Reference 3000. Instead, they are present to limit the possibility of improper instrument
operation or instrument damage from electrostatic discharge (static electricity) and other surge events such as
lightning.
Caution:
Two connections to earth ground in an electrochemical system can create a
hazardous condition. If your cell has an earth-ground connection, you must not connect the system ground
to earth. One symptom of multiple earth connections is opening of the Reference 30k Booster’s front-panel
fuses which protect the
Counter and Working leads.
Caution:
Two connections to earth ground in an electrochemical system can create a
hazardous condition. If your cell has an earth-ground connection, you must not connect the system ground
to earth. One symptom of multiple earth connections is opening of the Reference 30k Booster’s front-panel
fuses which protect the
Counter and Working leads.