Safety Test; Input Current Measurements; Power Source/Earth Connections - NEC AccuSync LCD51VM Series Service Manual

4. Safety Test

• Destination
• Applicable standards
• Unit class
• Ratings

4.1 Input Current Measurements

Under the measuring conditions specified below, an input current should be measured while the 50Hz input
voltage is maintained at 220V AC (+0 to -5V). The input currents measured should all confirm so they satisfy
the judgment standard. (The rear rating plates are the same as those for North America and Europe.
Therefore, measurements should also be based on this setting.)
(1) Measuring conditions
• Condition of the set
• Measuring conditions
(2) Judgment standard
• The input current should be kept below 0.35A +10%.

4.2 Power Source/Earth Connections

a. Checks on the power source/earth connections
The earth side of the cord or the earth wire of the inlet filter for the cord set should be visually checked to
see that it is connected to the chassis block of the unit as specified below.
1) The earth wire color should be spiral of green and yellow.
[Units applicable to UL60950 or IEC60950 (EN60950)]
2) The earth wire should be firmly connected to the chassis block by the use of a screw (See Note) of
3.5mm∅ in diameter.
Note: Spring washers or star washers should be used, without fail.
b. Earth resistance testing
This testing should be carried out prior to the dielectric strength test.
The earth resistance should be 0.1Ω or less when a current of 25A AC is carried between the earth side
of the cord (the plug block or the section closest to the plug where no plug is provided) and the metallic
block (the D-SUB connector) that is used as a safety earth for the unit.
Where the earth resistance exceeds 0.1Ω, the condition should be still acceptable if the earth resistance
is 0.1Ω or less when the resistance of the power cord is excepted.
: All over the world
: UL60950/C-UL/EN60950
: Class I units (the units protected against electric shocks by protective
earthing, or those equipped with 3-core power cords)
: AC100 - 240V 50/60Hz 0.7A/0.4A
: ON mode
: The inspection signal is set at "17" and "white" is displayed throughout
the screen.
At that time, the brightness and contrast should be kept under the
brightest condition.
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