Texas Instruments 880 User Manual page 85

Appendix D
Power Requirements and Grounding
0.1 POWER REQUIREMENTS
The Model 880 Printer can operate over four
ranges of single-phase RMS voltages.
•
100Va.cnominal +10%,-15%
•
120 Vac nominal + 10%, -15%
•
220 Vac nominal + 10%, -15%
• 240 Vac nominal + 10%, -15%
CAUTION
Refer to the identification label on
the back of your printer for correct
voltage levels. An incorrect voltage
can cause damage to the printer.
The Model 880 will operate normally from ac
mains at 47 to 63 hertz.
WARNING
Do not use a power receptacle that
does not accept a three-wire plug.
Do not cut the ground pin from the
plug. An electrical hazard can
result.
0.2 SAFETY CONSIDERATIONS
For the safety of the operator, and for correct
operation, the printer must be connected to
ground by inserting the power cable into a com-
patible three-pin receptacle which is connected to
ground as specified by the National Electrical
Code and local codes and ordinances. The fol-
lowing conditions can cause possible hazards or
can cause faulty printer operation:
•
•
•
•
•
Open safety ground
Safety ground connected to the hot lead
Safety ground connected to the neutral
lead in the receptacle
Safety ground connected to conduit only
Hot and neutral connections reversed in
receptacle
If a wall receptacle with correct wiring is not avail-
able, the user must have a correct receptacle
installed by a qualified technical person.
For correct operation, it is recommended that the
printer not be installed on the same circuit with
copy machines, water coolers, or similar devices
that cause power-line transients. If faulty printer
operation occurs as a result of the operation of
other devices, the user must connect the printer
to a different circuit or install devices to suppress
transient voltages.
0.3 EARTH GROUND
In some installations the earth ground of the
power receptacle is provided by a metal conduit
that connects to the neutral phase at the circuit-
breaker box. As determined by site conditions,
this metal conduit can conduct current from other
sources that can cause faulty operation of a
printer connected at the receptacle. To prevent
this occurrence, it is recommended that the earth
ground and neutral be isolated from the conduit
(except at the circuit-breaker) for the computer
system and printer circuit as shown in Figure 0-1.
This will assure that the protection ground con-
ducts only fault and leakage current from the
printer or computer system.
0-1