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Delta Conversion Function
5.5 Delta Conversion Function
The delta conversion function measures a three-phase line after converting a delta connection
into a Y connection (star connection) or vice versa. The conversion is performed using voltage
waveform data sampled at a frequency of 15 MHz between dierent channels based on the
formula.
Δ
–Y conversion
This function can be enabled when the wiring mode is set to 3P3W3M or 3V3A.
This function can measure phase voltages across internally-Y-connected motor coils even if
the motor is used as a delta-connected load, whose neutral point cannot be connected to the
instrument.
The voltage waveforms, various measured voltage values, and harmonic voltages are all inputted
as line voltages; however, they are calculated as phase voltages.
In 3P3W3M wiring mode
U3
U1
U2
A
C B
U3
U1
U2
A
C B
In 3V3A wiring mode
U3
U1
U2
A
C B
U2
U1
U3
A
C B
• In
Δ
–Y conversion, voltage waveforms are converted into vectors and analyzed using a virtual
neutral point.
• The result may dier from the actual phase voltages.
• In 3V3A wiring mode, active power is measured with the two-wattmeter method; however, the
converted value is equal to that measured with the three-wattmeter method.
• The two-wattmeter method is used to calculate active power in 3V3A wiring mode, but the three-
wattmeter method is used after conversion.
• Peak-over judgment uses not-converted values.
• When the voltage range is set to the auto-ranging, voltage range switching is determined by
multiplying the range by 1/
3
(multiplying by approximately 0.57735).
Various Functions
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