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Chapter 1 Installation and Preparation
Caution To protect the load and the RMX programmable power supplies, use a D
RP
that conforms to the following specifications.
• Reverse voltage withstand capacity–At least twice the rated output voltage of the RMX
programmable power supply.
• Forward current capacity–Three to ten times the rated output current of the RMX
programmable power supply.
• A diode with small loss.
• Be sure to take into account the heat generated by D
RP
. D
RP
will burn out with inadequate
heat dissipation.
Load Cables
Caution Risk of fire. Use load cables whose capacity is adequate for the
RMX programmable power supply’s rated output current. The output connector and
its surrounding area become hot. Use cables whose covers have heat resistance at
85 °C and higher.
Caution Risk of electric shock. Use the cable which has higher withstanding
voltage than the specified insulation voltage of the product to secure the double
insulation or reinforced insulation.
The current capacity of a load cable is dependent on the maximum allowable temperature of the
cable's insulation.
A cable’s temperature is determined by the resistive loss based on the current, the ambient
temperature, and the cable’s external thermal resistance. The following table shows the current
capacity of heat-resistant vinyl wires that have a maximum allowable temperature of 60 °C,
assuming that a wire is stretched out horizontally in air in an ambient temperature of 30 °C.
The current capacity must be reduced under certain conditions, such as when vinyl cables that
have a low heat resistance are used, when the ambient temperature is 30 °C or greater, or when
cables are bundled together and little heat is radiated.
Table 1-1. Current Capacity of Heat-resistant Vinyl Wires
Nominal
Cross-sectional
Area
AWG (Reference
Cross-sectional
Area)
Allowable
Current
(Ta = 30 °C)
Recommended
Current
2 mm
2
14 (2.08 mm
2
) 27 A 10 A
3.5 mm
2
12 (3.31 mm
2
) 37 A —
5.5 mm
2
10 (5.26 mm
2
) 49 A 20 A
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