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Touching the electrical parts may be fatal - even after the equipment has been disconnected from line power.
Also make sure that other voltage inputs have been disconnected, such as external 24 V DC, load sharing (linkage of DC intermediate circuit), as well as
the motor connection for kinetic backup.
Systems where adjustable frequency drives are installed must, if necessary, be equipped with additional monitoring and protective devices according to
the valid safety regulations, e.g., law on mechanical tools, regulations for the prevention of accidents, etc. Modifications on the adjustable frequency
drives by means of the operating software are allowed.
Hoisting applications:
The adjustable frequency drive functions for controlling mechanical brakes cannot be considered as a primary safety circuit. There must always be a
redundancy for controlling external brakes.
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
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 recommended.
"Protection mode” can be disabled by setting par. 14-26
Trip Delay at Inverter Fault
to zero, which means that the drive will trip immediately if one of
the hardware limits is exceeded.
NOTE!
It is recommended to disable protection mode in hoisting applications (par. 14-26
Trip Delay at Inverter Fault
= 0)
The DC link capacitors remain charged after power has been disconnected. To avoid electrical shock hazard, disconnect the adjustable
frequency drive from line power before carrying out maintenance. When using a PM motor, make sure it is disconnected. Before
servicing the adjustable frequency drive, wait the minimum amount of time indicated below:
Voltage
Power
Waiting Time
380–500 V
0.34–10 hp [0.25–7.5 kW]
4 minutes
15–100 hp [11–75 kW]
15 minutes
125–275 hp [90–200 kW]
20 minutes
250–800
kW
40
minutes
525–690 V
15–100 hp [11–75 kW] (frame size B
and C)
15 minutes
50–450 hp [37–315 kW] (frame size D) 20 minutes
500–1350 hp [355–1000 kW]
30 minutes
2.2.1 Disposal Instructions
Equipment containing electrical components may not be disposed of together with domestic
waste.
It must be separately collected with electrical and electronic waste according to local and cur-
rently valid legislation.
2 Safety and Conformity
FC 300 Design Guide
2-2
MG.33.BC.22 - VLT
®
is a registered Danfoss trademark
2