Lenze 8400 - Manual (Page 245)

Lenze · 8400 protec HighLine · Reference manual · DMS 3.0 EN · 03/2013 · TD05
245
5 Motor control (MCTRL)
5.10 Parameterisable additional functions
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5.10.2 Flying restart function
The flying restart circuit for asynchronous motors uses a simple motor model which requires
knowledge of the motor stator resistance RS and the rated motor current.

Tip!
In association with the flying restart function, we recommend information provided in this
documentation on the following topic:
 Automatic DC-injection braking (Auto-DCB) ( 249)
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. 0.5 ... 1.5 seconds. The duration is influenced by
the starting value. If the field frequency is not known, we recommend a fixed starting value of 10
Hz (or -10 Hz with systems rotating in negative direction).

Note!
• Currently, the flying restart circuit is only available for asynchronous motors. (A flying
restart circuit for synchronous motors is in preparation.)
• For a correct functioning of the flying restart circuit, we recommend to perform a
parameter identification first.  Automatic motor data identification ( 134)
• 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.
• On drive systems with feedback, you do not need to use the flying restart function
because the synchronisation to the speed detected by the feedback is always carried
out in a jerk-free manner.