Service and Maintenance 8
E364xA User’s and Service Guide 225
CC source effect (line regulation)
This test measures the immediate change in output current that results from a
change in AC line voltage from the minimum value (10% below the nominal input
voltage) to the maximum value (10% above the nominal voltage).
1 Turn off the power supply and connect the output to be tested as shown in
Figure 8-2 with the digital voltmeter connected across the current monitoring
resistor (R
M1
).
2 Connect the AC power line through a variable voltage transformer.
3 Turn on the power supply. Select the low voltage range (8 V/3 A)
[1]
, enable the
output, and set the display to the limit mode. When the display is in the limit
mode, program the voltage to the maximum programmable value and the
current to the full-scale rated value (3 A)
[1]
.
4 Operate the electronic load in the constant voltage mode and set its voltage to
8.0 V
[1]
. Check that the CC annunciator remains lit. If not lit, adjust the load so
that the output voltage drops slightly until the CC annunciator lights up.
5 Adjust the transformer to the low line voltage limit (104 Vac for nominal 115
Vac, 90 Vac for nominal 100 Vac, or 207 Vac for nominal 230 Vac). Record the
output current reading by dividing the voltage reading on the digital voltmeter
by the resistance of the current monitoring resistor.
6 Adjust the transformer to 10% above the nominal line voltage (127 Vac for a
115 Vac nominal input, 110 Vac for a 100 Vac nominal input, or 253 Vac for a
230 Vac nominal input). Record the current reading immediately by dividing
the voltage reading on the digital voltmeter by the resistance of the current
monitoring resistor. The difference between the current readings in step 5 and
step 6 is the load regulation current. The difference of the readings during the
immediate change should be within the following limits:
[1] For the E3646A model. For other models, refer to Table 8-5.
E3646A E3647A E3648A E3649A
0.55 mA 0.33 mA 0.75 mA 0.39 mA