Emerson 2202, Advanced User'S Manual

Page: 79 / 200

Introduction
Parameter
x.00
Parameter
description format
Keypad and
display
Serial
communications
CT Modbus
RTU
PLC Ladder
programming
CTSoft Menu 0
Advanced parameter
descriptions
Menu 5
Commander SK Advanced User Guide
79
Issue Number: 9 www.controltechniques.com
Else, if |active current| ≥ 0.7 x rated active current
V/f ratio = Normal V/f ratio
Although the V/f ratio varies, the value shown as Pr 5.06 does not vary from that set by the user.
Use to avoid instability on unloaded large motors.
0 Ur S Stator resistance and voltage offset measured on each run signal
The stator resistance (Pr 5.17 ) and the voltage offset (Pr 5.23 ) are measured and the parameters for the selected motor map are over-written each
time the drive is given a run signal. This test can only be done with a stationary machine where the flux has decayed to zero. Therefore this mode
should only be used if the machine is guaranteed to be stationary each time the drive is enabled. To prevent the test from being done before the flux
has decayed there is a period of 1 second after the drive has been in the ready state during which the test is not done if the drive is re-started. In this
case, previously measured values are used. The new values of stator resistance and voltage offset are automatically saved to EEPROM.
1 Ur No measurements
The stator resistance and voltage offset are not measured. The user can enter the motor and cabling resistance into the stator resistance parameter.
However this will not include resistance effects within the drive inverter. Therefore if this mode is to be used, it is best to use the auto-tuning stationary
test initially to measure the stator resistance.
2 Fd Fixed boost mode.
Neither the stator resistance nor the voltage offset are used, instead a fixed characteristic with boost applied as defined by Pr 5.15 is used. (see
Pr 5.09 on page 76)
Fixed boost mode should be used for multiple motor applications.
3 Ur A Stator resistance and voltage offset measured at first drive enable
The stator resistance and voltage offset are measured once, the first time the drive is enabled and run. After the test has been completed successfully
the mode is changed to Ur mode. The stator resistance and voltage offset are written to the parameters for the currently selected motor map and
these parameters along with this parameter are saved in the EEPROM.
If the test fails the stator resistance and voltage offset are not updated, the mode is changed to Ur, but no parameters are saved. If the drive is
powered down and back up, the drive will carry out another autotune when the drive is enabled and run.
4 Ur I Stator resistance and voltage offset measured at each power-up and after a drive default
The stator resistance and voltage offset are measured when the drive is first enabled after each power-up and after a drive default. The new values of
stator resistance and voltage offset are automatically saved to EEPROM.
5 SrE Square law characteristic
Neither the stator resistance nor the voltage offset are used, instead a fixed square law characteristic with boost applied as defined by Pr 5.15 is used.
(see Pr 5.09 on page 76)
The voltage boost level used in fixed boost mode and square law mode is defined by this parameter. See Pr 5.09 on page 76.
This voltage boost compensates for the voltage drop arising from the stator resistance.
5.14 Voltage mode select {41}
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
1 1 1 1
Range Ur S(0), Ur(1), Fd(2), Ur A(3), Ur I(4), SrE(5)
Default Ur I(4)
Update rate Background
5.15 Low frequency voltage boost {42}
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
1 1 1 1
Range 0.0 to 50.0% of motor rated voltage
Default 3.0
Update rate Background
5.16 Unused parameter
NOTE
NOTE