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2 Installing the Instrument
AC Mains Connections
AC Mains Considerations
Power Cable Connections
AC Mains Considerations
Keysight RPS models have a fully bi-directional three-phase ac input converter, which allows for
seamless bi-directional power flow between the ac mains and dc output terminals.
In a standard power supply, energy only flows from the ac to the dc output terminals. In a regenerative
power supply, energy also flows from the dc output terminals back to the ac mains whenever the unit is
sinking current, either from rapid down-programming of the output or from discharging an energy
source such as a battery. This return of energy back to the ac mains is referred to as regenerative
operation.
The ac input converter of the RPS unit employs firmware algorithms to maintain high power factor and
low total harmonic distortion across a wide range of operating conditions. For more information refer
to the ac input portion of the
Follow all wiring instructions for the power cord provided in this section of the manual. For example,
previous RPS units employed a connection to ac neutral, or the unit would not turn on. Later RPS
units no longer require a neutral connection. Refer to
Exceeding the ac input voltage rating or mis-wiring the line connection can create
permanent damage in the following devices.
The following components are used to provide immunity against line-to-line transients as high as 2 kV,
and line-to-ground transients as high as 4 kV:
300 Vrms voltage limiting devices are installed between the line and neutral connections.
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600 Vrms voltage limiting devices are installed between the line-to-line connections.
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A gas-discharge tube is installed between the neutral connection and chassis ground.
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Several internal protection functions are used to safeguard the instrument against abnormal line
conditions while also preventing ac mains islanding. The following conditions cause the instrument to
shut down:
If the line voltage is greater than 120% of the highest nominal rating for two line cycles.
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If the line voltage is less than 50% of the lowest nominal rating for four line cycles.
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If the line current is greater than 120% of the highest expected line current for about one second.
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If the line frequency shifts more than 2 Hz from its initial frequency for more than two seconds.
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If a four-cycle line dropout occurs.
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68
Characteristics
section.
Keysight RP7970 & RP7980 Series Operating and Service Guide
Power Cable Connections
for details.
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