Special Functions and Features
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4.
Connect the red voltage test lead to the "A" phase wire. The
phase angle indicated is the phase angle between the "A" phase
voltage and the "C" phase current.
5.
Press "SHIFT", then "
∆
PHASE". The display will indicate zero.
6.
Move the red voltage test lead to the "B" phase wire. The new
value displayed will be the phase angle between the "A" phase
voltage and the "B" phase voltage.
3.3.1 Using Fixed Offsets in Delta Phase Mode
Operating with one of three preset phase angle offsets can enhance
the basic capabilities of the Delta Phase mode. In addition to normal
Delta Phase operation, the operator has the choice of entering offset
values of 30, 60, or 90 degrees lag (current lagging voltage).
After selecting the offset value, the 918B will indicate zero because
the phase angle at the inputs is equal to the offset value.
All of the 918B measurement functions, which involve phase (W,
PF, vars, and phase) will account for the entered offset. For
example, if the offset entered is 30 degrees lag, and the instrument is
used to measure a circuit in which the current lags the voltage by 30
degrees, then the power factor indicated would be 1.0.
Procedure
1.
To enter an offset value, first set the unit to the Phase mode by
pressing "PHASE".
2.
Press "SHIFT" then "
∆
PHASE" to switch to the Delta Phase
mode. Pressing the "SHIFT"/"
∆
PHASE" key sequence again
will cause the display to momentarily indicate "
∆
Ph = 30 Deg
LAG", and will select this value as the offset.
3.
Repeating the "SHIFT”/”
∆
PHASE" sequence will select 60
degrees, then 90 degrees offset, then will finally disable the
Delta Phase mode.