
Parameter
Name / value range / [default setting]
Info
0x2D4B:005
Motor overload monitoring (i²*t): Thermal load
•
Read only
7.7.2
Current limits
For the purpose of current limitation, a maximum overload current can be set for the inverter.
If the current consumption of the motor exceeds this current limit, the inverter changes its
dynamic behaviour, in order to counteract this exceedance.
Details
If the change in the dynamic behaviour carried out by the inverter does not
result in exiting the overcurrent state, the inverter outputs an error.
Overload during acceleration in motor mode
•
The inverter prolongs the acceleration ramp to keep the current on or below the current
limit.
•
A longer time than is required for reaching the frequency setpoint is set.
Overload during deceleration in generator mode
•
The inverter prolongs the deceleration ramp to keep the current on or below the current
limit.
•
A longer time than is required for reaching standstill is set.
Increasing load with a constant frequency
•
If the motor current limit value is reached:
•
The inverter reduces the effective speed setpoint until a stable working point is set or an
effective speed setpoint of 0 min
-1
is reached.
•
If the load is reduced, the inverter increases the effective speed setpoint until the set-
point speed is reached or the load reaches the current limit value again.
•
When the generator current limit value is reached:
•
The inverter increases the effective speed setpoint until a stable working point is reached
or up to the maximum permissible output frequency
0x2916 (PAR 211)
.
•
If the load is reduced, the inverter reduces the effective speed setpoint until the setpoint
speed is reached or the load reaches the current limit value again.
•
If an abrupt load is building at the motor shaft (e.g. drive is blocked), the overcurrent
switch-off function may respond.
Parameter
Name / value range / [default setting]
Info
0x6073
(PAR 324)
Max current
(Max current)
0.0 ... [200.0] ... 3000.0 %
Maximum overload current of the inverter.
•
100 % ≡ rated motor current
0x6075 (PAR 323)
•
If the current consumption of the motor exceeds this current limit,
the inverter changes its dynamic behaviour, in order to counteract
this exceedance.
•
If the change in the dynamic behaviour carried out by the inverter
does not result in exiting the overcurrent state, the inverter outputs
an error.
Note!
This parameter is not identical to the so-called ultimate motor current
I
ULT
!
•
The ultimate motor current set in
0x2D46:001 (PAR 353/001)
is a limit
value for synchronous motors that serves to protect their magnets.
•
The value to be set here should always be considerably below the ulti-
mate motor current!
0x2D88
(PAR 104)
Actual motor current
(Act. motor current)
•
Read only: x.x A
Display des present current-r.m.s. value.
Motor control
Motor protection
Current limits
93
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