Artesis AMT Toolkit - Setting and Checking the Input Connections

AMU Use
22
3.4.4. Setting and checking the input connections
When the CHECK MOTOR menu option is selected, AMU first determines the relative order
of the voltage phases using the V1 channel as an arbitrary reference. It then attempts to
place the current channel pairs in the correct order and polarity. The order determined by
AMU can be displayed by entering the EDIT SETTINGS menu and selecting:
MENU: Edit Settings / Phase Ordering / Phase Order
On this menu, the voltages are denoted by the letters R, S, T and currents by r, s, t. A – sign
preceding each letter indicates that the corresponding signal has an extra 180º of phase
shift (i.e. that the polarity of the signal is reversed). Similarly, a + sign preceding a letter
indicates that the polarity is correct. For example:
R-s+T+r+S-t
The above phase ordering display would indicate that relative to the first voltage (R) phase
on input V
1
, the S and T phases (on V
3
and V
2
respectively) are reversed. The order of the
current inputs is also incorrect with IS connected to I
11
- I1
2
, I
R
connected to I
21
- I
22
and I
T
connected to I
31
- I
32
. Furthermore, the polarities of the two currents, I
S
and I
T
, have been
reversed (I
11
has been exchanged with I
12
and I
31
with I
32
).
NOTE
Once AMU has determined the correct phases, the
user should not change the input connections without
running CHECK MOTOR again.
The algorithm used by AMU to determine the phase order yields two solutions depending
on the motor loading and extra information is required to obtain the correct sequence. To
this end, AMU compares the measured RMS values for the currents with the nominal
current entered by the user. If the ratio of the measured current to the nominal current is
greater than the value of the Load threshold (expressed as a percentage), the motor is
assumed to be working under loaded conditions and the appropriate solution is chosen.
Otherwise the motor is assumed not to be loaded. It is thus important to enter an accurate
value for the nominal current. Even so, it is still possible for AMU to choose the wrong
solution which will yield unrealistic values for the phase angle when the loading on the
motor changes in use. AMU provides the possibility of overriding the detected phase
sequence from the menu item Order Override under:
MENU: Edit Settings / Phase Ordering / Order Override