Control Techniques Commander SE Advanced User's Manual page 106

21.12
0 to 99.99
This parameter stores the stator resistance of the machine for vector mode operation. Although it is designated as read/write,
it is read only if vector mode 0 is selected with parameter 5.14. If the drive cannot achieve the necessary current levels to
measure the stator resistance in mode 0 or during an autotune (e.g. there is no motor connected to the drive), an rS trip will
occur and the value in parameter 21.12 remains unchanged. If the necessary current level can be achieved, but the
calculated resistance exceeds the maximum values for the particular drive size, an rS trip will occur and parameter 21.11 will
contain the maximum allowed value. The maximum value can be calculated from the following formula:
Rs = V
max
where:
V
DC full_scale
I
full_scale
When an autotune is carried out by the drive, the calculated stator resistance is automatically saved.
21.13
The stator resistance test is carried out at half and full rated motor current. A current is applied in the y axis of the reference
frame with zero frequency, and so DC current flows in all three phases of the machine. The results are as shown on the
following diagram.
Voltage
V
2
V
1
V
offset
The gradient of the line gives the stator resistance, cabling resistance and resistance effects within the drive. The units are
converted to ohms before being stored in 21.12.
The drive must produce a voltage before any current flows, shown as V
good performance at low frequencies where the machine terminal voltage is small this offset must be taken into account. The
value shown in 21.13 is given in volts, representing the voltage that would be applied on the U phase output as a DC level.
The voltages on the other two phases would be -V
an automatic measurement procedure should be used, either by using the autotune or selecting mode 0 (see 5.14).
21.14
000.0 ~ 500.0
The value of inductance stored in this parameter is the total leakage inductance (L
measured at the start of the magnetising current test and stored in this parameter.
The total leakage inductance can be calculated from the steady state per phase equivalent circuit of the motor:
L ' = L + (L
s 1
L ' is used for automatic calculation of the motor power factor during the autotune test.
s
21.15
This parameter will change from a logic 0 to 1 when motor map 2 becomes active.
The second motor map will become active when 11.45 is set to a 1 and the drive is in a disabled, tripped or standby mode. If
the drive is running, 11.45 will be set to a 1 but the second motor map will not be implemented.
This parameter can be programmed to a digital output to close a second motor contactor when motor map 2 becomes active.
See Chapter 12 Applications for a second motor map set-up example.
106
Motor 2 stator resistance
0.0
/ (I * 2)
DC full_scale full_scale
= Maximum measurable DC Bus voltage (420V or 830V)
= Drive rated current √2 x 2.2
Motor 2 voltage offset
0 ~ 25.5
I /2 I
rated rated
Motor 2 leakage inductance
.L / (L + L ))
2 m 2 m
Motor map 2 active
0 ~ 1 0
Ω
RW Uni
V RW Uni
. This includes IGBT voltage drops etc. To obtain
offset
/2. It is not possible for the user to measure this voltage easily, and so
offset
mH RO Uni
RO Bit
P
P
') of the motor. The value can be
s
P
Commander SE Advanced User Guide
Issue Number: 4