Lambda LP Series - Connection Methods; Two-Wire and Four-Wire Connections; Programmed Voltage Connections; Constant Current Operation Connections

Two-Wire Connection, Figure 3. The . two-wire connection, with local sensing, is the
,..,..--- .. connection suitable for application with relatively constant load.
Four-,.Wire Connection, Figure 4. The four-wire connection with remote sensing, provides
complete compensation for the DC voltage drops in the connecting cables. · Compensation for
lead drop is also valid for gradual changes of load current. ·
Pro rammed Voltage Connections, Using External Resistor, Figure 5. Discrete voltage
steps can be programmed with a resistance vo tage divider valued at 200 ohms/volt output
and a shorting-type switch as shown in figure 5. When continuous voltage variations are
required, use variable resistor with the same 200 ohms/volt ratio in place of the resistive
voltage divider and shorting-type switch. Use a low temperature coefficient resistor to
assure most stable operation.
As shown in figure 5, voltages can be programmed utilizing either local or remote
sensing connections, as desired.
Programmed Voltage Connections Using Programming Voltage, Figure 6. The power
supply voltage output can be programmed with an externally connected programming power
supply. The output voltage of the programmed supply will maintain a one-to-one ratio with
the voltage of the programming supply.
The programming supply must have a reverse current capability of 6 rna. minimum.
Alternatively, when supplies with less than 6 rna. reverse current capability are
used, a resistor capable of drawing 6 rna. at the minimum programming voltage must be
cctnnected across the output terminals of the supply. This programming supply must be
/" "'""" . rated to handle all excess resistor current at the maximum programming voltage.
Ct">nnections For Operation as a Constant Current Source
Automatic Crossover Constant Current Connections, Figure 3. Figure 3 shows the con-
nections which are used when operating the power supply as a constant current source with
automatic crossover, using local setting of current control*
*Setting control for output currents below rated limits can result in no output or no
regulation.
In this mode of operation, when the load voltage increases, due to changing load
resistance, to the limit of the OUTPUT VOLTAGE control setting, the power supply
crossover circuit will cause the unit to operate as a constant voltage supply.
Connections For Series Operation
The voltage capability of LP power supplies can be extended by series operation of
two LP power supplies of equal* voltage ratings. A maximum of 300 volts can be con-
nected between either the +DC or -DC terminal and chassis ground, and a maximum voltage
capability of 500 volts is possible for model LP415.
*For applications using supplies of unequal ratings, consult factory for details of
operation.
Diodes CR1 and CR2, must each be capable of withstanding the maximum .rated
current of the units in the series combination, figure 7.
IM-LP400
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