Which products are affected? 9300 vector 22…90 kW SW V7.1
Applications
Applications with heavy starting, e. g. extruder
Function description
In the V/f characteristic control mode (C0006 = 5) a constant voltage boost can be selected under code C0016 when the motor stands still or the motor speeds are very low. This value refers in [%] to the rated motor voltage indicated under code C0090.
If due to the setting under C0016 no current or an inconstant current is set the voltage boost can further be increased by means of the boost correction in order to inject a current into the motor which is constant and high enough.
An insufficient voltage boost can be identified by the following drive behaviour:
The desired torque is not generated during standstill. When accelerating a load out of standstill a current overshoot occurs since the motor has not been magnetised sufficiently before. OC1 may trip. Note:
If problems occur concerning the current injection into the motor we recommend to operate the drive controller with a sine-modulated switching frequency (C0018 = 0, 1, 4, 5, 6). It is not recommended to use the flat-top modulation (C0018 = 2 or 3).
Attention:
If the motor is operated in stand still mode for a longer period of time there is the risk (especially for small motors) that the motor is destroyed by overtemperature.
We recommend to connect a thermal contact (normally closed), PTC or KTY and to activate the motor temperature monitoring of the drive controller. Self-ventilated motors are to be operated with an external fan if necessary. Setting the voltage boost:
A detailed function description can be found in the enclosure (pdf file, 56 kB).
