Danfoss VLT AutomationDrive FC 300 Programming Manual page 11

1 Introduction
Protection Mode
Once a hardware limit on motor current or dc-link voltage is exceeded the frequency converter will enter "Protection mode". "Protection mode" means a
1
change of the PWM modulation strategy and a low switching frequency to minimize losses. This continues 10 sec after the last fault and increases the
reliability and the robustness of the frequency converter while re-establishing full control of the motor.
In hoist applications "Protection mode" is not usable because the frequency converter will usually not be able to leave this mode again and therefore it
will extend the time before activating the brake – which is not recommendable.
The "Protection mode" can be disabled by setting par. 14-26
immediately if one of the hardware limits is exceeded.
NB!
It is recommended to disable protection mode in hoisting applications (par. 14-26
10
Trip Delay at Inverter Fault
to zero which means that the frequency converter will trip
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MG.33.M8.02 - VLT is a registered Danfoss trademark
FC 300 Programming Guide
Trip Delay at Inverter Fault
= 0)