Application:
- Blower
- Drives with big moment of inertia
Description:
Thanks to the flying restart circuit, the controller can be enabled while the motor is running. It detects automatically the current motor speed and starts the motor control with this speed. This prevents a motor braking to zero speed with subsequent acceleration.
In order to detect the current motor speed automatically the motor is driven with low magnetisation, that is to say a reduced motor voltage is applied at different output frequencies. The resulting motor current has its minimum when the set output frequency matches the actual motor frequency. The search operation can be influenced via the current value when searching, the searching speed. In addition the reference value, which determines the output frequency at which the search is started, can be adapted.
Activation
- C0142 = 0: Start lock
- => Flying restart circuit inactive; Start protection, that is to say a signal change of control enable (terminal 28) is necessary
- C0142 = 1: Auto start (Lenze default setting)
- => Flying restart circuit inactive; automatic start
- C0142 = 2: Start lock flying restart
- => Flying restart circuit is activated after start enable (after power-on, reset of messages or warnings (t > 0,5 s) or Trip-Reset) by a signal change of control enable (terminal 28)
- C0142 = 3: Auto flying restart
- => Flying restart circuit is activated directly after start enable and controller enable. No change of the controller enable signal is necessary.
Parameterisation
- C0145: Selection of the reference for searching
- – C0145 = 0: Maximum speed (C0011), with unknown motor speed
- – C0145 = 1: Last current motor speed (Lenze default setting)
- – C0145 = 2: Setpoint speed, with known motor speed
- C0146: Influences the current value when searching (reference value 1250 equal approximate Imax of the controller)
- – Decrease the value for motors with low centrifugal mass (the speed increases already during searching).
- C0147: Influences the searching speed
- – One search operation takes approx. 1 to 2 s. For large motors, it may be necessary to reduce the searching speed (decrease value).
Tip in control mode 'vector control' (C0006 = 1)
You can do without flying restart circuit if a suitable setpoint becomes immediately active after controller enable (e.g. setpoint to NSET-CINH-VAL).
In case of operating with encoder feedback you can abandon the flying restart circuit, because the signal MCTRL-NACT becomes active as setpoint at NSET-CINH (in comparison with signal configurations C0005 = 1XXX .... 5XXX).
This reduces flying restarts to approx. 200 ms.
