Kikusui KHA3000, Operation Manual, Page: 107 / 392

5
KHA3000
107
61000-3-2
Setting the Harm
onic Test
Delta Transform (Star-delta conversion)
The delta transform function associated with the voltage measurement function of this
product is used to convert the measured phase voltages to voltages between lines (line
voltages). Even if the actual measurement circuit is wired for a three-phase four-wire (3P4W)
system, the measurement of three-phase three-wire (3P3W) EUT can be performed. The
delta transform function is enabled when 3P3W is selected in the Wiring Method menu.
p. 53
In the case of standard wiring where no voltmeter is connected to external measurement
points, the voltmeter connection is switched inside this product according to the selection
made in the Wiring Method menu. Accordingly, it is unnecessary to think about the selection
between phase voltage and line voltage measurements.
However, if any voltmeter is connected to an external measurement point, such a selection
cannot be made automatically. Because typical AC power supplies that are used for tests are
in 3P4W configuration, it is generally necessary to change the wiring of the voltage
measurement points for 3P4W circuits to that of 3P3W circuits.
As the phase voltages measured in a 3P4W circuit can be converted to line voltages by using
the delta transform function, any 3P3W EUT can be tested even if the actual measurement
circuit is wired for a 3P4W system. The following figures show the 3P3W and 3P4W circuits to
test a 3P3W EUT. In the case of the 3P4W circuit, the delta transform function is used.
See
CAUTION
• Don't use the delta transform function when the actual measurement circuit is wired for
3P3W.In such a case, delta transform is unnecessary. If the delta transform function is
used, the voltage measurements will be in error.
A
V
A
V
A
V
U
V
W
G
N
G
U
V
V
W
G
L1
L2
L3
V
V
SOURCE LOAD
KHA3000
A
V
A
V
A
V
U
V
W
N
N
G
G
U
V
V
W
G
L1
L2
L3
V
V
SOURCE LOAD
KHA3000
3P3W circuit
3P3W EUT
3P4W circuit
3P3W EUT