Agilent Technologies E3630A Manual De Funcionamiento Y Servicio página 89

Current Limit
k. Disconnect all loads from the supply.
l. Connect the test setup shown in Figure A-5 to the +20-volt output.
Substitute a short for R and leave the load circuit switch open.
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m. Set the voltage of the ±20V supplies to 20 volts.
n. Close the load switch and determine the current flow
through the current sampling resistor (meter shunt) by
measuring its voltage drop with the DVM. The current
should be 0.55A±5% (0.5225A to 0.5775A).
o. Check the current limit of the -20V supply in the same
way. Its short-circuit current should also be 0.55A±5%
(0.5225A to 0.5775A).
p. Connect the test setup shown in Figure A-5 to the +6V
output. Close the switch, set the total resistance of R
the current sampling resistor to an initial value of 2.4 Ω or
greater, and set the output voltage to 6 volts.
q. Reduce the value of R
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put current indicated by the DVM. The current should
increase to a maximum of 2.75A±5% (2.6125A to
2.8875A) before it begins to decrease.
r. Connect a short across R
indicated by the DVM. The short-circuit current of this out-
put should be 1A±15% (0.85A to 1.15A). Disconnect the
test setup from the supply.
Load Regulation (Load Effect)
Definition: The immediate change,
of dc output voltage resulting from a change in load resis-
tance from open circuit to the value that yields maximum
rated output current (or vice versa).
To check the load regulation:
a. Connect the test equipment across the output of the +20V supply as
shown in Figure A-6. Operate the electronic load in constant current
mode and set its current to the full rated value of the +20V supply.
Input off the electronic load.
b. Turn on the supply and adjust its voltage to its maximum
rated value. Then input on the electronic load.
c. Record the voltage indicated on the DVM.
d. Operate the electronic load in open (input off) mode and
recheck the DVM indication immediately. The readings'
difference during the immediate change should be within
0.01% plus 2mV of the reading in step (c).
e. Repeat steps (a) through (d) for each of the remaining supply
outputs.
Figure A-6. Basic Test Setup
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gradually while observing the out-
and then recheck the current
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E , in the static value
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Line Regulation (Source Effect)
Definition: The immediate change, E
output voltage resulting from a change in ac input voltage from a
minimum to a maximum value (±10% of nominal voltage).
To check the line regulation:
a. Connect a variable autotransformer between the input
power source and the power supply line plug.
b. Connect the test equipment across the output of the +20V sup-
ply as shown in Figure A-6. Operate the electronic load in con-
stant current mode and set its current to the full rated value of
the +20V supply. Input off the electronic load.
c. Adjust the autotransformer for a low line input (-10% of nominal volt-
age).
d. Turn on the power, adjust the output of the supply to its
maximum rated voltage, then input on the electronic load.
and
Record the DVM indication.
e. Adjust the autotransformer for high line voltage input
(+10% of nominal voltage) and recheck the DVM indica-
tion immediately. The readings' difference during the
immediate change should be within 0.01% plus 2mV of
the reading in step (d).
f. Repeat steps (b) through (e) for each of the remaining supply out-
puts.
Ripple and Noise
Definition: Ripple and noise are measured in the rms or peak-
to-peak value over a 20 Hz to 20 MHz bandwidth. Fluctuations
below the lower frequency limit are treated as drift.
RMS Measurement
The rms measurement is not an ideal representation of the
noise, since fairly high output noise spikes of short duration
could be present in the ripple and not appreciably increase
the rms value.
To measure the ripple and noise of the rms value on each
output supply output:
a. Connect the test equipment across the output of the
+20V supply as shown in Figure A-7.
b. Turn on the supply and push +20V METER switch.
c. Turn up output voltage to the full rated value.
d. Check that the rms noise voltage at the true rms voltme-
ter is less than 0.35mV.
e. Repeat for the remaining supply outputs.
Figure A-7. Ripple and Noise rms Measurement Test
A-5
, in the static value of dc
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