Control Techniques Commander SK User Manual

Introduction Parameter x.00
Parameter
description format
Keypad and
display
CT Modbus
RTU
User
programming
CT Soft Menu 0
Advanced parameter
descriptions
Menu 4
Commander SK Advanced User Guide 49
Issue Number: 2 www.controltechniques.com
The current demand is derived from the torque demand. Provided the motor is not field weakened the torque and current demands are the same. In
field weakening the current demand is increased with reduced flux:
The current demand is subject to the current limits.
This parameter defines the current limit as a percentage of the rated active current. When the motor rated current is set lower than the drive rated
current, the maximum value of this parameter increases to allow larger overloads.
Therefore, by setting the motor rated current to a lower value than the drive rated current, it is possible to have a current limit greater then 165%. An
absolute maximum current limit of 999.9% is applied.
In frequency control mode (Pr 4.11 = 0), the drive output frequency is modified if necessary to keep the active current within the current limits as
shown below:
The active current limit is compared with the active current and if the current exceeds the limit the error value passes through the PI controller to give
a frequency component which is used to modify the ramp output. The direction of the modification is always to reduce the frequency to zero if the
active current is motoring, or to increase the frequency towards the maximum if the current is regenerating. Even when the current limit is active the
ramp still operates, therefore the proportional and integral gains (Pr 4.13 and Pr 4.14) must be high enough to counter the effects of the ramp. For
method of setting the gains see Pr 4.13 and Pr 4.14 on page 50.
In torque control mode the current demand is limited by the active current limit. For operation of this mode see Pr 4.11 on page 50.
This is the main torque reference parameter. A positive value is required for torque to be applied in the forward direction, and a negative value is
required for torque to be applied in the reverse direction.
For a negative value, program a digital input to the analog input invert bit. This will give a negative value on the analog input destination parameter.
4.04 Current demand
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
1 11111
Range ±TORQUE_PROD_CURRENT_MAX %
Update rate Background
4.05 to 4.06 Unused parameters
4.07 Symmetrical current limit
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
11 1 111
Range 0 to MOTOR1_CURRENT_LIMIT_MAX %
Default 165.0
Second motor
parameter
Pr 21.29
Update rate Background
4.08 Torque reference
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
11 11
Range ±USER_CURRENT_MAX %
Default 0.0
Update rate Background
Current demand
Output frequency (Pr 5.01)
Rated frequency (Pr 5.06)
---------------------------------------------------------------------------=
PPr4.13
IPr4.14
Current limit
active
1
0
Active
current
limit
Post ramp
reference
Ramp
Active
current
-
+

Control Techniques Commander SK Specifications

General

Brand	Control Techniques
Model	Commander SK
Category	Inverter
Language	English