Protection Mode - Danfoss VLT Programming Manual

1 Introduction

Protection Mode

Once a hardware limit on motor current or dc-link voltage is exceeded the drive will enter "Protection mode". "Protection mode" means a change of the
1
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 drive while re-establishing full control of the motor.
In hoist applications "Protection mode" is not usable because the drive 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
of the hardware limits is exceeded.
NB!
It is recommended to disable protection mode in hoisting applications (par. 14-26
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Trip Delay at Inverter Fault
to zero which means that the drive will trip immediately if one
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VLT HVAC Drive Programming Guide
Trip Delay at Inverter Fault
= 0)