d. Use a power/voltage source to generate an AC voltage.
e. Press STOP (F1).
f. Check that the level of this current, and the current readout
on the QA-90’s display are equal. If necessary, adjust the
voltage to be equal on UUT and reference. The constant
used is the SP/VDML U-constant.
g. Repeat the measurement, but with DC voltage.
h. Press GO BACK (F2) four times to go to Manual Test Se-
tup Window 1.
8. Supply Voltage. An insulated transformer is used for this mea-
surement, except for step 7.f. below.
a. Press Supply Voltage (F6).
b. Check the voltage between LIVE and NEUTRAL on the
front panel terminals with a calibrated instrument.
c. Select Live - Neutral (F7) and press START (F1).
d. Press STOP (F1). Check the voltage.
e. Select Neutral - Ground (F7) and press START (F1).
f. Press STOP (F1). Check the voltage.
g. Connect a variac to the terminals on the front panel and
check the voltage. The Live - Neutral setting is used to
measure, for example, 70 and 250 VAC. It is not necessary
to use an insulated transformer.
h. Press GO BACK (F2) to return to Manual Test Setup Win-
dow 1.
9. Current Consumption. This measurement is done with a resis-
tive load connected to the mains outlet on the front panel of the
QA-90. The reference digital multimeter (HP34401 or similar), in
current (AC) mode, is in series with the load. Use the digital mul-
timeter in the 0 - 3 A range, and the same instrument with a cur-
rent probe (HP34330A or similar) in the range > 3 A. The probe
and digital multimeter are calibrated together.
a. Press Current Consumption (F5).
b. Press START (F1).
c. Press STOP (F1). Check that the UUT and the reference
digital multimeter values are equal. If they are not equal, ad-
just the CC I-constant.
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