TM 11-6625-2958-14&P
3-43 For reasonable load lead lengths, remote sensing greatly improves the performance of the supply. However, if the load is located a considerable distance from the supply, added precautions must be observed to obtain satisfactory operation. Notice that the voltage drop in the load leads subtracts directly from the available output voltage and also reduces the amplitude of the feedback error signals that are deveIoped within the unit. Because of these factors it is recommended that the drop in each load lead not exceed 0.5 volt. If a larger drop must be tolerated, please consult an HP Sales Engineer.
NOTE
Due to the voltage drop in the load leads, it may be necessary to readjust the current limit in the remote sensing mode.
3-44 Observance of the precautions in Paragraph 3-43will result in a low dc output impedance at the load. However, another factor that must be considered is the inductance of long load leads. This causes a high ac Impedance and could affect the stability of the feedback loop seriously enough to cause oscillation. If this is the case, it is recommended that the following actions be taken:
a. Adjust equalization control R47 to remove oscillation, or to achieve best possible transient response for given long load lead configuration. Refer to Paragraph 5-27for discussion of transient response measurement.
b. If performing adjustment in step (a) above does not remove oscillation, disconnect output capacitor A3C3 and connect a capacitor having similar characteristics (approximately the same capa- citance, the same voltage rating or greater, and having good high frequency characteristics) directly across load using short leads. Readjust equalization control R47 as in step (a) above after making this change. In order to gain access to capacitor A3C3, it is necessary to remove the RFI assembly as described in steps (a) through (c) of Paragraph
5-67.Lead from positive side of capacitor (shown arrowed In Figure 7-2)can then be unsoldered from A3 interconnection circuit board.
3-45 To employ remote sensing with any method of remote programming or with any method of combining more than one supply discussed in the Preceding or following paragraphs, use the following pro- cedure:
a. Remove the two external leads connecting the sensing terminals (±S) to the output bus bars (±OUT).
b. Connect a lead from the +S terminal to the positive side of the load, and connect another lead
from the -S terminal to the negative side of the load. Note that there may be more than one lead connected to the +S and -S terminals.
3-46AUTO-PARALLEL OPERATION (Figure 3-10)
3-47 Two or more power supplies can be connected in an Auto-Parallel arrangement to obtain an output
Figure 3-10.Auto-Parallel Operation,
Two and Three Units
