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Table 3-3. Stranded Copper Wire Ampacity
Wire Size
Cross Section
AWG
Area in mm^
Ampacity
NOTES:
22
5,0
1. Ratings for AWG-sized wires are
20
8.33
derived from MIL-W-5088B •
0,75
10
Ratings for metric-sized wires are
18
15.4
derived from lEC Publication 335-1.
1
13.5
16
19.4
2, Ampacity of aluminum wire is
1,5
16
approximately 84% of that listed
14
31,2
for copper wire,
2,5
25
12
40
3. When two or more wires are bundled
4
32
together, ampacity for each wire
10
55
must be reduced to the following
6
40
percentages:
8
75
10
63
2 conductors 94%
6
100
3 conductors 89%
4
135
4 conductors 83%
2
180
5 conductors 76%
0
245
4. Maximum temperatures: Ambient, 55°C;
Conductor, 105°C
3-29
Either positive or negative voltages can be obtained
from the supply by grounding one of the output terminals. It
is best to avoid grounding the output at any point other than
the power supply output terminals to avoid noise problems
caused by common-mode current flowing through the load
leads to ground. Always use two wires to connect the load to
the supply regardless of where or how the system is ground¬
ed. Never ground the system at more than one point. This sup¬
ply can be operated with either output terminal up to ± 240 volts
dc (including output voltage) from ground.
3-30
The PARD specifications in Table T1 apply at the
power supply output terminals, However, noise spikes
induced in the load leads at or near the load may affect the
load although the spikes are inductively isolated from the power
supply. To minimize voltage spikes at the load, connect a bypass
capacitor as shown in Figure 3-5, With this setup, peak-to-peak
noise at the load can actually be reduced to a level well below
the value specified at the power supply output terminals,
3-31
Overvoltage Protection (OVP)
3-32
The overvoltage trip point is adjusted at the front panel.
The approximate trip voltage range is from zero volts to 65 volts.
When the OVP circuit trips, the power supply output is
disabled and delivers no output power, and the OVP and
DISABLED indicators turn on.
3-33
Adjustment. OVP is set by the recessed single-turn
OVP ADJUST potentiometer on the front panel. Rotating the
control clockwise sets the trip voltage higher. (It is set to
maximum at the factory.) When adjusting the OVP trip point,
the possibility of false tripping must be considered. If the trip
voltage is set too close to the supply's operating voltage, a tran¬
sient in the output would falsely trip the OVP. For this reason
it is recommended that the OVP trip voltage be set higher than
the output voltage by at least 1 volt (see NOTE following
Paragraph 3-42). To adjust the OVP trip voltage, proceed as
follows;
a. Turn on supply and hold DISPLAY OVP pushbutton in.
b. Insert a small-blade screwdriver through hole in front panel
and adjust OVP trip voltage to desired level.
POWER
SUPPLY
Figure 3-5.
Connecting a Bypass Capacitor
3-7
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