HT instruments VEGA78 - Manual (Page 110)

VEGA78
EN - 108
7.3. USING OF METER IN A THREE PHASE 3 WIRE SYSTEM
CAUTION
 The maximum voltage among B1, B2, B3, B4 and BE inputs is 1000V /
CAT IV 600V to ground. Do not measure voltages exceeding the limits
prescribed by this manual. Should you exceed the voltage limits you
could damage the instrument and/or its components or endanger your
safety.
 If possible, before connecting the meter to the electrical equipment under
test turn the power supply off.
Fig. 187: Meter connection in a three phase 3-wire system
1. Check and modify the basic settings of meter if necessary (see § 5.3.1). Set 3WIRE
system option.
2. Connect voltage test leads on Phases L1, L2, L3, and Ground cables respecting the
colours as shown in Fig. 187. Verify the result “123” at display relative to a correct
phase sequence indication (see § 5.2.1) and perform the corrections if necessary.
3. Connect the transducer current clamps on Phase L1, L2, L3 cables as shown in Fig. 187
respecting the clamp’s arrow direction indicating the current standard sequence from
generator to load. On Real Time Values’ section screens always verify the positive
value of Active Power and the power factor relative to load which should be
normally inductive before starting a recording. Reverse the clamp by 180 degrees on
cables in case of negative readings.
4. Supply the electrical installation under test in case it was temporarily put out of service
for meter connection. The values of parameters are shown by meter at display in Real
Time Values’ section (see § 5.2).
5. Press SAVE key if a instantaneous sample of display values (Instant) should be saved
(see § 5.5). Use HOLD function to stopping the values at display if necessary.
6. Check all settings before start a recording (see § 5.4). Press GO/STOP key to enable
and disable a recording on meter (see § 5.4.10).