Delta Tau Geo Brick, User Manual

Page: 214 / 294

Geo Brick Drive User Manual
Motor Setup 214
Motor Slip Gain: Ixx78
Ixx78 controls the relationship between the torque command and the slip frequency of magnetic field on
the rotor of an AC Induction (Asynchronous) motor. While it is usually set experimentally, The Motor
Slip Gain Ixx78 can be calculated either from Motor Name Plate, or Rotor Time Constant.
Calculating Slip Gain From Name Plate Data. Example:
A 4-pole induction motor has a rated speed of 1760 rpm at a 60 Hz electrical frequency:
#define LineFrequency 60 ; Electrical Line Frequency at this speed [Hertz] -USER INPUT
#define Mtr4Poles 4 ; Motor #4 Number of Poles -USER INPUT
#define We
P7007 ; Electrical Frequency, in Radians/Sec
#define Mtr4Wm P7008 ; Motor #4 Rated mechanical pole frequency, in radians/sec
#define Tp P7009 ; Phase Clock, in Seconds
#define PI 3.1416 ; PI Constant
Tp=1/(PhaseClk*1000)
; Note that PhaseClk is defined in Clock Calc.
We=LineFrequency*2*PI ;
Mtr4Wm=(Mtr4Speed*2*PI*Mtr4Poles)/(60*2) ;
I478=(We-Mtr4Wm)*Tp*I477/32768
; Motor #4 Slip Gain Constant
Calculating Slip Gain From Rotor Time Constant. Example:
An Induction Motor with a Rotor time constant of 0.75 seconds:
#define Tp P7010 ; Phase Clock, in Seconds
#define Mtr4Tr 0.75 ; Motor #4 Rotor Time Constant, in Seconds -User Input
Tp=1/(PhaseClk*1000)
; Note that PhaseClk was defined earlier in I2T Settings
I478=Tp/Mtr4Tr
; Motor #4 Slip Gain Constant
ADC Offsets: Ixx29, Ixx79
The ADC offsets importance may vary from one system to another, depending on the motor(s) type and
application requirements. They can be left at default of zero especially if a motor setup is to be
reproduced on multiple machines by copying the configuration file of the first time integration. However,
they should ultimately be set to minimize measurement offsets from the A and B-phase current feedback
circuits, respectively (read in Suggested M-variables Mxx05, Mxx06).