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2.3.1 NiCad battery pack
When the PhD Ultra is operated in the diffusion
mode, the rechargeable NiCad battery pack will
provide up to 12 hours of continuous use. The
NiCad pack is a sealed assembly that may not be
disassembled in the field. The NiCad battery may
be recharged while the pack is installed in the
instrument, or the battery pack may be removed
from the instrument and recharged separately in the
PhD Ultra Fast Charger.
Fully assembled NiCad battery packs may be
removed or replaced while the instrument is being
used in a hazardous location.
The PhD Ultra must be located
in a non-hazardous location during the charging
cycle. Charging the PhD Ultra in a hazardous
location may impair intrinsic safety.
The PhD Ultra is Classified by Underwriters
Laboratories, Inc. and the Canadian Standards
Association as to Intrinsic Safety for use in Class
I, Division 1, Groups A, B, C, & D Hazardous
Locations. This classification is void while the
PhD Ultra is operated while connected to the
battery charger in hazardous areas.
2.3.2 Disposable alkaline battery pack
The PhD Ultra may also be equipped with a battery
pack designed to hold a set of 3 AA disposable
alkaline batteries. When the PhD Ultra is operated
in diffusion mode, the alkaline battery pack will
provide up to 12 hours of continuous use. The
alkaline pack must be removed from the instrument
in order to replace the batteries. The alkaline
battery pack is removed in the same manner as the
NiCad pack. To maintain intrinsic safety the
alkaline battery pack cover is held in place by a
captive screw that is located in the center of the
underside of the battery pack. To open the alkaline
pack, use a screwdriver to loosen the screw and
gently remove the cover.
Make sure that replacement batteries are properly
aligned in the battery pack housing before returning
the instrument to service.
The alkaline battery pack must
be located in a non-hazardous location
whenever the alkaline batteries are removed
from it. Removing the alkaline batteries from
the alkaline battery pack in a hazardous location
may impair intrinsic safety.
2.3.3 Low battery alarms
The PhD Ultra is designed to automatically
determine which type of battery pack has been
installed, and use the appropriate low battery
alarms. Alarms will be activated whenever battery
voltage is too low to allow the safe operation of the
instrument.
Battery pack voltage may be checked at any time
while the instrument is in normal operation by
pressing the mode button to access the runtime
screen. Allow the PhD Ultra to operate two to three
minutes before checking battery voltage. A reading
of 3.8 Volts or higher indicates that either type of
battery pack has sufficient power to provide eight
hours of continuous operation.
2.3.3.1 Low battery alarm settings for NiCad
battery packs
When NiCad battery pack voltage is reduced to 3.3
Volts, an audible alarm will sound, and the display
screen will indicate that a low battery condition
exists. At this stage, the low battery alarms may be
silenced for a fifteen-minute period by pressing the
mode button. The alarm will continue to sound
every fifteen minutes until the voltage reaches 3.25
Volts.
The initial low battery screen alternates with a
second screen that indicates that the alarm may be
silenced by pressing the mode button.
When battery pack voltage has dropped to 3.25
Volts it is no longer safe to continue to use the
instrument until the battery has been recharged. At
this point the alarm will begin to sound continuously,
and may no longer be silenced by pushing the mode
button. If voltage drops below 3.25 Volts the PhD
Ultra will display a "Dead Battery" message to warn
the user of imminent shut down. The instrument will
then automatically turn itself off.
The PhD Ultra NiCad battery pack should be
recharged as soon as possible after any low battery
alarm. It is important to recharge or replace the
battery pack before further use.
2.3.3.2 Low battery alarm settings for alkaline
battery packs
If the PhD Ultra has been equipped with a
disposable alkaline battery pack, the initial low
battery alarm will be activated when voltage is
reduced to 3.2 Volts. Protective shutdown occurs at
3.1 Volts.
2.3.4 Recharging NiCad battery packs
Standard accessories included with every “NiCad”
instrument include a slip-in PhD Ultra “Fast
Charger”. Each standard Fast Charger assembly
