Lenze E84AVHC Series - 5.4.1.2 Defining current limits (Imax controller)

Firmware ≤ 05.00 - DMS 4.2 EN - 02/2010 L 115
8400 HighLine | Parameter setting & configuration
Motor control (MCTRL)
V/f characteristic control (VFCplus)
The V/f characteristic shape is defined by selecting the corresponding operating mode in
C00006
:
 C00006
= 6: Linear characteristic
 C00006
= 8: Quadratic characteristic
 C00006
= 10: Freely definable characteristic
 Tip!
You can find detailed information on freely definable V/f characteristics in the
subchapter entitled "Defining a user-defined V/f characteristic
". ( 123)
5.4.1.2 Defining current limits (Imax controller)
The V/f characteristic control (VFCplus) and the V/f control (VFCplus + encoder) operating
modes are provided with a current limitation control which is decisive for the dynamic
behaviour under load and counteracts exceedance of the maximum current in motor or
generator mode. This current limitation control is called I
max
control.
 The efficiency (motor current) measured by the I
max
control is compared with the
current limit value for motor load set in C00022
and the current limit value for
generator load set in C00023
.
 If the current limit values are exceeded, the controller changes its dynamic behaviour.
Motor overload during acceleration
The controller prolongs the acceleration ramp to keep the current on or below the current
limit.
Generator overload during deceleration
The controller prolongs the deceleration ramp to keep the current on or below the current
limit.
Increasing load with constant speed
 If the motor current limit value is reached:
– The controller reduces the effective speed setpoint until a stable working point is set
or an effective speed setpoint of 0 rpm is reached.
– If the load is reduced, the controller increases the effective speed setpoint until the
setpoint speed is reached or the load reaches the current limit value again.
 When the generator current limit value is reached:
– The controller increases the effective speed setpoint until a stable working point is
set or the maximally permissible speed (C00909
) or output frequency is reached
(C000910
).
– If the load is reduced, the controller reduces the effective speed setpoint until the
setpoint speed is reached or the load reaches the current limit value again.
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