Lenze 8400 motec - Manual (Page 148)

5 Motor control (MCTRL)
5.10 Parameterisable additional functions
148 Lenze · 8400 motec · Reference manual · DMS 4.1 EN · 08/2013 · TD05
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5.10.2 Flying restart function
The flying restart circuit uses a simple model of an asynchronous motor which requires knowledge
of the motor stator resistance RS and the rated motor current.

Tip!
If you parameterise a mechanical holding brake (
C02580 <>0), we recommend you to read
the information regarding the flying restart function provided in this documentation on
the following topic:
 Automatic DC-injection braking (auto DCB) ( 151)
General information
This function serves to activate a mode which is used to "catch" a coasting motor during operation
without speed feedback. This means that the synchronicity between controller and motor is to be
adjusted in such a way that a jerk-free transition to the rotating machines is achieved in the instant
of connection.
The drive controller determines the synchronicity by identifying the synchronous field frequency.
Duration
The "catching" process is completed after approx. 1 ... 2 seconds. The duration is influenced by the
starting value. If the field frequency is not known, we recommend the preset starting value of 10 Hz.
Short overview of the relevant parameters:

Note!
• For a correct functioning of the flying restart circuit, we recommend to perform a
parameter identification first.  Automatic motor data identification ( 88)
• The flying restart function works safely and reliably for drives with great centrifugal
masses.
• Do not use the flying restart function if several motors with different centrifugal
masses are connected to a controller.
• After the controller is enabled, the motor can start for a short time or reverse when
machines with low friction and low mass inertia are used.
• The flying restart function serves to identify max. field frequencies up to ±200 Hz.
• When power-adapted standard asynchronous motors are used (rated motor power
approximately corresponds to the rated inverter power), a motor parameter
identification is not required.
Parameter Info Lenze setting
Value Unit
C00990 Flying restart fct.: Activate Off
C00991 Flying restart fct.: Process -n...+n | Last output frequency
C00992 Flying restart fct.: Start frequency 10 Hz
C00994 Flying restart fct.: Current 25.00 %