Ametek Elgar ReFlex Power Operation Manual page 248

ReFlex Power™
W V
IRE OLTAGE
For applications where regulation is important, the contribution of the load wiring
to voltage drop from the output terminals of the DC modules to the load must be
considered. The wire gauge must be selected to maintain an acceptable total
voltage drop for the load wiring under the maximum peak current. The resistance
of the load wiring must be determined for the sum total length of the output lead
and the return lead. The total voltage drop is the sum of the individual drops in
the output and return leads. Table 5-10 gives the resistance per meter (m) of
various wire gauges at 20°C and 100°C.
Use the following equation to calculate the resistance for other wire
temperatures:
R = R20°C x [1 + 0.004 x (T - 20°C)]
where,
The voltage drop (per output or return lead) could be calculated using the
following equation:
V = I x L x R20°C x [1 + 0.004 x (T - 20°C)]
where,
N
OISE AND
To minimize noise pickup or radiation from load circuits, load wires and remote
sense wires should be twisted-pair with minimum lead length. Shielding of the
sense leads may be necessary in high noise environments. Even if noise is not a
concern, the load and remote sense wires should be twisted-pairs to reduce
coupling between them, which could impact the stability of the output converter. If
connectors are utilized for the power and sense leads, be careful not to introduce
coupling between the leads. Ensure that the connector terminals for the sense
leads are in adjacent locations, and minimize the physical loop area of the
untwisted portions.
M380056-01 Rev L
D
ROP
R = resistance, Ω/m, at temperature T
R20°C = resistance, Ω/m, at 20°C
T = temperature of wire, °C
V = total voltage drop, V
I = current, A
L = length of wire, m
R20°C = resistance of wire, Ω/m, at 20°C
T = temperature of wire conducting current, °C
I E
MPEDANCE FFECTS
DC Power Supplies
6-45