Power Supply Units
Section 3-4
Surge Current
The surge current for the DC Power Supply Unit under maximum load conditions
is shown below. Consider the surge current characteristics when selecting the
power source, switches, breakers, etc.
Electric
current
(A)
Time (ms)
Input: 24 VDC; load: 12 A at 5 V (maximum load); ambient temp.: 25°C.
Use crimp terminals for wiring. Do not connect bare stranded wires directly to
terminal blocks. Use M3.5 screws for tightening crimp terminals.
7 mm max.
7 mm max.
Tighten the screws on the terminal block to a torque of 0.8 N S m.
20 mm max.
M3.5 screw
Tightening torque: 0.8 N S m
Caution Abide by the following precautions when wiring the Power Supply Units. Failure
!
to abide by these precautions my cause faulty operation or damage to the Unit.
• Be sure that no wire clippings or other foreign materials enter the Units when
wiring.
• Provide circuit breakers and other protective devices to protect the system
again external short circuits.
• Check and recheck all wiring before supplying power to the system.
• After wiring the terminals check the terminal block to be sure it is firmly locked
in place.
3-4-2 Grounding
The line ground (LG: ) terminal of the Power Supply Unit is a noise-filtered
neutral terminal. Short the line ground terminal to the ground (GR: ) terminal to
improve noise resistance.
To avoid electrical shock, attach a grounded AWG 14 wire (cross-sectional area
2
of 2 mm ) to the ground terminal. The ground resistance must be 100
W or less
and must be checked periodically to be sure that environmental conditions have
not deteriorated ground capacity. Do not use a wire longer than 20 m.
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