Remedies For Undesired Drive Behaviour - Lenze 8400 StateLine C Reference Manual

8400 StateLine C | Reference manual
Motor control (MCTRL)
V/f characteristic control - energy-saving (VFCplusEco)
5.5.5

Remedies for undesired drive behaviour

Drive behaviour
Inadequate smooth running at low speeds, especially in
the case of operation with a long motor cable
Problems in case of high starting duty (great mass
inertia)
Drive does not follow the speed setpoint
Insufficient speed constancy at high load (setpoint and
motor speed are not proportional anymore)
"Clamp operation active" error message (OC11):
Controller cannot follow dynamic processes, i.e. too
short acceleration/deceleration times in terms of load
ratios.
Motor stalling in the field weakening range
(adaptation especially required for small machines)
Speed variations in no-load operation for speeds > 1/3
rated speed.
152
Phone: 800.894.0412 - Fax: 888.723.4773 - Web: www.clrwtr.com - Email: info@clrwtr.com
Remedy
Automatic motor data identification ( 112)
Reduce the influence of the Eco function by increasing
the minimum voltage V/f (C00977).
1. Set motor control VFCplus with linear characteristic
(C00006 = 6).
2. Adapting the Vmin
3. Again set motor control VFCplusEco
The current controller intervenes in the set field
frequency to limit the controller output current to the
maximum current (C0022, C0023). Therefore:
• Prolong acceleration/deceleration times:
C00012: Accel. time - main setpoint
C00013: Decel. time - main setpoint
• Consider a sufficient magnetising time of the motor.
Depending on the motor power, the magnetising
time amounts to 0.1 ... 0.2 s.
• Increase the maximally permissible current:
C00022: Imax in motor mode
C00023: Imax in generator mode
• Make adaptations for the Eco function:
– Improving the behaviour at high dynamic load
changes. ( 150)
– Adapting the slope limitation for lowering the Eco
function. ( 151)
– Optimising the cos/phi
• Increase slip compensation (C00021).
Important: Unstable drive due to overcompensation!
• With cyclic load impulses (e. g. centrifugal pump), a
smooth motor characteristic is achieved by smaller
values in C00021
Note: The slip compensation is only active for operation
without speed feedback.
• Increase the gain of the I
• Reduce the reset time of the I
• Prolong the acceleration time (C00012)
• Prolong the deceleration time (C00013)
• Make adaptations for the Eco function:
– Improving the behaviour at high dynamic load
changes. ( 150)
– Adapting the slope limitation for lowering the Eco
function. ( 151)
• If motor power < inverter power:
Set C00022 to I
• Reduce dynamic performance of setpoint generation
• Make adaptations for the Eco function:
– Improving the behaviour at high dynamic load
changes. ( 150)
– Adapting the slope limitation for lowering the Eco
function. ( 151)
Minimise speed oscillations with oscillation damping
(C00234).
L
Firmware ≤ 11.00 - DMS 8.0 EN - 10/2011
boost. ( 134)
(C00006 = 11).
controller. ( 151)
(possibly negative values).
controller (C00073)
max
controller (C00074)
max
= 2 I
max rated motor