2-7
IM WT1801-01EN
• Star-delta transformation (Star>Delta)
You can use the data from a three-phase, four-wire system to compute the data of a delta connection from the
data of a star connection.
R
S
T
R
S
T
When you perform delta computation on wiring unit ΣA, the available measurement functions are as follows.
ΔU1rms[UrsA], ΔU1mn[UrsA], ΔU1dc[UrsA], ΔU1rmn[UrsA], ΔU1ac[UrsA]
ΔU2rms[UstA], ΔU2mn[UstA], ΔU2dc[UstA], ΔU2rmn[UstA], ΔU2ac[UstA]
ΔU3rms[UtrA], ΔU3mn[UtrA], ΔU3dc[UtrA], ΔU3rmn[UtrA], ΔU3ac[UtrA]
ΔUΣrms[UΣA], ΔUΣmn[UΣA], ΔUΣdc[UΣA], ΔUΣrmn[UΣA], ΔUΣac[UΣA]
ΔIrms[InA], ΔImn[InA], ΔIdc[InA], ΔIrmn[InA], ΔIac[InA]
I
I
R
S
T
U
U
U
I
N
I1
I2
I3
U1
U2
U3
Urs
Utr
Ust
In
±
±
±
±
±
±
* In the measurement functions,
rms
,
mn(mean)
,
dc
,
rmn(r-mean)
, and
ac
are the delta computation modes.
A
indicates the wiring unit.
• Delta-star transformation (Delta>Star)
Using the data from a three-phase, three-wire system that uses a three-voltage, three-current method, you
can compute the data of a star connection from the data of a delta connection. This function is useful when
you wish to observe the phase voltage of an object that has no neutral line, such as a motor. The center
N of the star connection is computed as the center of the delta connection. If the actual center of the star
connection does not match the center of the delta connection, an error results.
R
S
T
R
S
T
When you perform delta computation on wiring unit ΣA, the available measurement functions are as follows.
ΔU1rms[UrA], ΔU1mn[UrA], ΔU1dc[UrA], ΔU1rmn[UrA], ΔU1ac[UrA]
ΔU2rms[UsA], ΔU2mn[UsA], ΔU2dc[UsA], ΔU2rmn[UsA], ΔU2ac[UsA]
ΔU3rms[UtA], ΔU3mn[UtA], ΔU3dc[UtA], ΔU3rmn[UtA], ΔU3ac[UtA]
ΔUΣrms[UΣA], ΔUΣmn[UΣA], ΔUΣdc[UΣA], ΔUΣrmn[UΣA], ΔUΣac[UΣA]
ΔIrms[InA], ΔImn[InA], ΔIdc[InA], ΔIrmn[InA], ΔIac[InA]
ΔP1[PrA]
ΔP2[PsA]
ΔP3[PtA]
ΔPΣ[PΣA]
2 Fundamental Measurement Conditions