Input Voltage Limit; Input Current Limit; Input Power Limit - Ametek Amrel PLA Series Operation Manual

INPUT VOLTAGE LIMIT

The programmable electronic load can handle voltages with in nominal values and surge voltages less than 5% above
nominal value. The Over-voltage protection will be tripped when the input voltage exceeds 5% of nom inal value. For
CV mode application, the input power source should have current limit capability to prevent exceeding the electronic
load's input current range.
Two over voltage protection features have been provided. 1) Over voltage protection to limit maximum current to 5%
above nominal value. 2) Software selectable, the user can set and read back the input protection voltage level.
WARNING
High voltage and high current operation may result in a fault condi tion, shutting down the Load input. E nsure
that the maximum voltage and current applied to the electronic load does not exceed the power rating.

INPUT CURRENT LIMIT

The nominal current values are indicated in the specification datasheet. During Load bank operation in C V (Constant
Voltage) mode, limiting the input current at high voltages become a critical factor. The internal structure of the Load
Bank and the Over-Current protection will limit the maximum current to less than 5% above nominal rated current.
However, the combined input current and voltage can easily exceed the maximum rated power. If the power overload
condition persists over a time period, the accumulated over-power energy will trigger the hardware OP protection, and
control the input current to not exceed 120% of max rated power. Fo r CC mode operation, the input power source should
be a CV source or operate in CV mode, to avoid potential unstable conditions caused b y two Constant Current Control
loops. As for overpower conditions in CC mode, please limit the input voltage to prevent the OP fault condition shutting
down the Load input.
Two over current protection features have been provided. 1) Over current protec tion to limit maximum current to 5%
above nominal value. 2) Software selectable, the user can set and read back the input protection current level.
WARNING
High voltage and high current operation may result in a fault condi tion, shutting down the Load input. E nsure
that the maximum voltage and current applied to the electronic load does not exceed the power rating.

INPUT POWER LIMIT

The programmable electronic load is designed to handle power up to 110% of Max Power Rating, with input voltage and
current below the max rated specifications. As a recommendation, the input power source should not exceed the max
rated power, to avoid fault conditions shutting the Load input off. As indicated in the specification sheet, Constant Power
mode requires a current limit for each range (CPL, C PM, and CPH), which cannot exceed the corresponding current range
max value (CCL, CCM, and CCH).
WARNING
Anticipate the Maximum output of the power source carefully and consider the worst-case scenario.
maximum power range of the load should be higher than the output power of the source. High voltage and h igh
current operation may result in a fault condition, shutting down the Load input.
For C P mode application, the programmable electronic load can be set to maximum power dissipation with the following
limitations. Input must be within maximum voltage and current ratings. For example, PLA1.2K-120-200, the max rated
values are 120V/200A/1200W. Therefore, the maximum power will be limited to a combination of "voltage x current
values" equating to 1,200W. Thus, CP mode is limited by the hardware's maximum current, voltage and power ratings.
M470039-01 REV-F
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