A-4
CONSTANT VOLTAGE (CV) TESTS
CV Setup. For all CV tests set the output current at full rated
output to assure CV operation. The onset of constant current
can cause a drop in output voltage, increased ripple, and
other performance changes not properly ascribed to the con-
stant voltage operation of the supply.
Load Regulation (Load Effect)
Definition: CV Load regulation is the change in the steady
state value of dc output voltage due to a change in load resis-
tance from open circuit to full load or from full load to open cir-
cuit.
Test Parameters:
Measured Variable: Output Voltage
Expected Results: Less than 0.01% plus 2 mV
Test Procedure:
a.
Connect the test equipment as shown in Figure A-4.
Operate the electronic load in constant current mode
and set its current to the full rated value of the power
supply (6 A for E3614A, 3 A for E3615A, 1.7 A for
E3616A and 1 A for E3617A).
b.
Turn the supply's power on and turn CURRENT con-
trol fully clockwise.
c.
Turn up output voltage to the full rated value (8 V for
E3614A, 20 V for E3615A, 35 V for E3616A and 60 V
for E3617A) as read on the digital voltmeter.
d.
Record the output voltage at the digital voltmeter.
e.
Operate the electronic load in open(input off) mode.
f.
When the reading settles, record the output voltage on
the digital voltmeter again. Check that the two recorded
readings differ less than 0.01% of output voltage plus 2
mV.
Figure A-4. Basic Test Setup
Line Regulation (Source Effect)
Definition: Line regulation is the change in the steady state
value of dc output voltage due to a change in ac input voltage
from a minimum to a maximum value(±10% of nominal volt-
age).
Test Parameter:
Measured Variable: Output Voltage
Expected Results: Less than 0.01% plus 2 mV
Test Procedure:
a.
Connect the test equipment as shown in Figure A-4.
Operate the electronic load in constant current mode
and set its current to the full rated value of the power
supply.
b.
Connect the supply to the ac power line through a
variable autotransformer which is set for low line volt-
age(104 Vac for nominal 115 Vac, 90 Vac for nominal
100 Vac, and 207 Vac for nominal 230 Vac).
c.
Turn the supply's power on and turn CURRENT con-
trol fully clockwise.
d.
Adjust VOLTAGE control until the front panel VOLTS
display indicates exactly the maximum rated output
voltage.
e.
Record voltage indicated on the digital voltmeter.
f.
Adjust autotransformer to high line voltage(127 Vac
for nominal 115 Vac, 110 Vac for nominal 100 Vac,
and 253 Vac for nominal 230 Vac).
g.
When the reading settles, record the output voltage
again. Check that the two recorded readings differ
less than 0.01% of output voltage plus 2 mV.
Load Transient Response Time
Definition : This is the time for the output voltage to return to
within a specified band around its voltage following a change
from full load to half load or half load to full load.
Test Parameter:
Measured Variable: Output Voltage Transients
Expected Results: Less than 50 usec (at 15 mV from
base line)
Test Procedure:
a.
Connect the test equipment as shown in Figure A-4,
but replace the DVM with the oscilloscope. Operate
the electronic load in constant current mode.
b.
Turn the supply's power on and turn CURRENT con-
trol fully clockwise.
c.
Turn up output voltage to the full rated value.
d.
Set the electronic load to transient operation mode
between one half of supply's full rated value and sup-
ply's full rated value at a 1 KHz rate with 50% duty
cycle.
e.
Set the oscilloscope for ac coupling, internal sync and
lock on either the positive or negative load transient.
f.
Adjust the oscilloscope to display transients as in Fig-
ure A-5.
g.
Check that the pulse width of the transients at 15 mV
from the base line is no more than 50 usec as shown.
+
-
+S
OUT
-S
+
-
+
-
CV
+
-
CC
A1 A2 A3
A4
A5
VREF
ELECTRONIC
LOAD
+
-
DIGITAL
VOLTMETER
Rs
-
+
TO
DVM
POWER SUPPLY
UNDER TEST
MASTER
LOCAL
SLAVE
REMOTE
Model
Rs
E3614A, 15A, 16A
E3617A
0.1 ohm 0.1% 10W
1 ohm 1% 5W
M/S 1
M/S 2
CV
CC
SENSE
