KEPCO RA 19-1U Operator Manual - Manual (Page 42)

2-26
RA 19-1U 020413
• Where 115V a-c source power is used, Kepco recommends the use of the line cords,
P/N 118-0506 supplied (North American style plug, 15A maximum, 6 ft. long).
• Wire size is determined by the maximum rated source current for each 1U HSF power
supply and the number of power supplies installed. For lower system power configura-
tions, smaller wire can be used; contact Kepco Applications Engineering for assistance.
2.10.2.1 EMI COMPLIANCE
Depending on the application and system environment, special source power considerations
may be required to meet listed Input EMI specifications for HSF power supplies, particularly
FCC Class B. It may be necessary to add external source power filtering, such as installing
snap-on ferrite beads on the line cord wires of the RA 19-1U as close to the input a-c terminal
block as possible. Another option is to add an in-line cabinet-mounted EMI filter (available from
a number of manufacturers) between the source power and the RA 19-1U line cord. For addi-
tional assistance, contact Kepco Applications Engineering.
2.10.3 CONTROL SIGNAL CONNECTIONS
Access to the control signal (I/O) connector for each 1U HSF power supply is provided via the
15-pin D-subminiature connectors on the rear panel of the rack adapter (see Figure 1-4). Two
mating connectors (Kepco P/N 142-0449) are provided in a plastic bag. Consult PAR. 2.4 and
the 1U HSF operator's manual for instructions on wiring and use of these control lines.
2.10.4 OUTPUT LOAD CONNECTIONS
Load connections to the rack adapters are achieved via two terminal blocks located on the
backplate assembly. Wires must be sized according to expected current. Wire size range is 24-
14 AWG; torque to 4 lb-in (0.4 N•M) maximum. (Sensing connections are made through the I/O
mating connector, PAR. 2.4.1)
NOTE!
REGARDLESS OF OUTPUT CONFIGURATION, OUTPUT SENSE
LINES MUST BE PROPERLY CONNECTED FOR OPERATION.
2.10.4.1 REDUCING RIPPLE AND NOISE
Ripple and noise are measured under nominal load conditions to provide the rated output volt-
age/current of the 1U HSF power supply. Measurement of ripple/noise is illustrated in Figure 2-
18. It is most important to minimize impedance between the power supply output and the load.
As the length of load wires increases, ripple and noise may increase proportionally, therefore
length and placement are critical for minimum ripple and noise. A filter consisting of a 10pF
multi-layer ceramic capacitor for high frequency filtering in parallel with a 0.01
µF capacitor must
be used to eliminate unwanted ripple and noise pickup on the load wire. For noise-sensitive
applications the load wires and sense wires must be twisted and/or shielded.