1-9
IM 253710-01E
Functions
1
• Measurement function of the motor module
The following seven types of numerical data can be determined. For details related
to the determination of measurement functions, see “Chapter 15” or “Appendix 2.”
dc
Yes
No
1
Yes
No
k
Yes
No
All (No ( ))
Yes
Yes
Torque( )
Speed, Sync,
Slip, Pm,
Motor efficiency
(
η
mA or
η
mB),
Total efficiency
(
η
mA or
η
mB)
Chars and numbers inside ( )
Measurement
Function
Yes
: Numerical data exist
• The meaning of measurement functions with parentheses varies depending on
the characters or numbers that are inside the parentheses as follows:
• dc: Indicates numerical data of the DC component.
• l: Indicates numerical data of the fundamental wave.
• k: Indicates numerical data from 2nd to Nth order harmonics. N is the upper
limit of the harmonic order under analysis (see section 17.5). The upper limit
is determined automatically (maximum is 500) by the frequency of the PLL
source.
• All: No parentheses are appended after the measurement function. Indicates
numerical data related to all waveforms including the fundamental and
harmonics.
Element number
When an input module is installed in a slot that is located on the rear side of the main
unit, the slot combined with the input module is referred to as an element. The main
unit can contain up to four elements which are numbered from one to four. On power
measurement modules, one voltage and current pair can be input to each element.
The element number is appended to the symbols that were defined in the earlier
section, “Harmonic measurement function on each power measurement module” so
that the correspondence can be seen. For example, “U1(2)” represents the 2nd order
harmonic voltage of element 1.
Wiring method
The wiring method is the method by which the signals that are input to each element
are combined. Different selections are possible depending on the number of
elements that have power measurement modules installed. In some cases, only one
type of wiring method can be selected, while in other cases, two types of wiring
methods can be selected. When two types of wiring methods are selected, “A” or “B”
is appended to the symbols that were defined in the earlier section “Harmonic
measurement function of the average or the sum of the power measurement modules
(
Σ
function)” so that the correspondence can be seen.
For example, “U
Σ
A(2)” represents the average value of the 2nd order harmonic
voltage of power measurement modules that are combined using wiring method A.
PLL source «For procedures, see section 5.1.»
When measuring harmonics, the fundamental period (period of the fundamental
signal) must be determined in order to analyze the higher orders. The PLL (phase
locked loop) source is the signal that is used to determine the fundamental period.
Specify a signal that has the same period as the signal being measured. Selecting a
signal with little distortion or fluctuation for the PLL source will result in a stable
harmonic measurement. An ideal signal would be a rectangular wave with an
amplitude that is greater than or equal to 50% of the measurement range (see section
1.3).
1.2 Measurement Modes and Measurement/Computation Periods
