3.14.5 14-3* Current Limit Control
The adjustable frequency drive features an integral current limit controller which is activated when the motor current, and thus the torque, is higher than
the torque limits set in par.4-16
When the current limit is reached during motor operation or regenerative operation, the adjustable frequency drive will try to reduce torque below the
preset torque limits as quickly as possible without losing control of the motor.
While the current control is active, the adjustable frequency drive can only be stopped by setting a digital input to
Coast inverse
[2] or
Coast and reset
inv.
[3]. Any signal on terminals 18 to 33 will not be active until the adjustable frequency drive is no longer near the current limit.
By using a digital input set to
Coast inverse
[2] or
Coast and reset inv.
[3], the motor does not use the ramp-down time, since the adjustable frequency
drive is coasted.
14-30 Current Lim Cont, Proportional Gain
Range:
Function:
100 %*
[0 - 500 %]
Enter the proportional gain value for the current limit controller. Selection of a high value makes
the controller react faster. Too high a setting leads to controller instability.
14-31 Current Lim Contr, Integration Time
Range:
Function:
0.020 s*
[0.002 - 2.000 s]
Controls the current limit control integration time. Setting it to a lower value makes it react faster.
A setting too low leads to control instability.
3.14.6 14-4*Energy Optimization
Parameters for adjusting the energy optimization level in both Variable Torque (VT) and Automatic Energy Optimization (AEO) mode.
Automatic Energy Optimization is only active if par.1-03
, is set for either
Auto Energy Optim. Compressor
[2] or
Auto Energy Optim.
VT
[3].
14-40 VT Level
Range:
Function:
66 %*
[40 - 90 %]
Enter the level of motor magnetization at low speed. Selection of a low value reduces energy loss
in the motor, but also reduces load capability.
This parameter cannot be adjusted while the motor is running.
14-41 AEO Minimum Magnetization
Range:
Function:
40. %*
[40 - 75 %]
Enter the minimum allowable magnetization for AEO. Selection of a low value reduces energy loss
in the motor, but can also reduce resistance to sudden load changes.
14-42 Minimum AEO Frequency
Range:
Function:
10 Hz*
[5 - 40 Hz]
Enter the minimum frequency at which the Automatic Energy Optimization (AEO) is to be active.
14-43 Motor Cos-Phi
Range:
Function:
0.66 N/A* [0.40 - 0.95 N/A]
The cos(phi) setpoint is automatically set for optimum AEO performance during AMA. This parameter
should normally not be altered. However, in some situations it may be necessary to enter a new
value to fine tune.
3 Parameter Description
VLT
®
HVAC Drive Programming Guide
3-140
MG.11.C6.22 - VLT
®
is a registered Danfoss trademark
3