Rockwell Automation SA3100 Distributed Power System Drv Config,Program - Manual (Page 124)

C-2 SA3100 Drive Configuration and Programming
C.2 Vector Algorithm Gain Variables
The vector algorithm gain variables are used to adjust the gain of the vector control
algorithm. The no load stator current variable can be generated automatically by using
the enable tuning command in register 100/11000. The value generated by the
system should not require adjustment. If this value is modified outside of acceptable
limits, the new value will be ignored and the last acceptable value entered will be
used. Bit 8 in warning register 203/1203 will also be set to indicate the value entered
was invalid.
STATOR_T_E4% Stator Time Constant
The value of the Stator Time Constant is used
to adjust the gain of the current minor loop.
The value is entered in seconds times 10000,
e.g., 50 msec (0.05 Sec) is entered as 500.
Units: Secs
∗
10000
Default Value: 10
Low Limit: 0
High Limit: 10000
Step: 1
STATOR_IZ_E1% No Load Stator Current
The value in this variable represents the
amount of magnetizing current (flux).
This value is entered in amps times 10, e.g., a
no load stator current of 10 amps is entered as
100.
Units: Amps
∗
10
Default Value: 10
Low Limit: 0
High Limit: 8486
Step: 1
Verifying STATOR_IZ_E1% When Using High Slip Motors
The value in local tunable STATOR_IZ_E1% is generated automatically by the
system by setting the Enable Auto Tune bit in the Drive Control register (register
100/1100, bit 1, PMI_TUN@). However, if a high slip motor is being driven, the
value calculated for this variable may not be correct. With high slip motors, it is
important to verify the value in this variable using the following procedure:
Step 1. With no load, command the motor to its synchronous speed with no load.
Synchronous speed in RPM = 120
∗
fo/n, where fo = rated motor frequency
in hertz and n = number of motor poles.
Step 2. At synchronous speed, monitor motor voltage using register 209.
Step 3. Modify the value in STATOR_IZ_E1% until motor voltage is approximately
97% of rated motor voltage.
Example:
The following example applies the above procedure to verify the value of
STATOR_IZ_E1% for a 60 Hz, 4-pole high slip motor with a rated motor voltage of
460V, a rated speed of 1755 RPM, and rated full load current of 11.9A:
Step 1. Command the motor to its synchronous speed with no load:
Synchronous speed = 120
∗
60/4 = 1800 RPM,
Command = (1800/1755)
∗
4095 = 4200 counts.
Step 2. At synchronous speed, monitor motor voltage using register 209.
Step 3. Modify the value in STATOR_IZ_E1% until motor voltage is between 472V
and 435V. The higher value is preferred.