FC 300 Operating Instructions
How to Install
" Additional Connections
" ControlofMechanicalBrake
In hoisting/lowering applications, you need to be able to control an electro-mechanical brake.
• Control the brake u sing any relay output or digital output (terminal 27 or 29).
• Keep the output closed (voltage-free) as long as the frequency converter is unable to ‘support’
the motor, for example due to the load being too heavy.
• Select Mechanical brake control [32] in par. 5-4* for applications with an electro-mechanical brake.
• The brake is released when the motor current exceeds the pre set value in par. 2-20.
• The brake is engaged when the output frequency is less than the frequency set in par. 2-21 or
2-22, and only if the frequency converter carries out a stop command .
If the frequency converter is in al a rm mode or in an overvoltage situation, the
mechanical immediately brake cuts in.
" Parallel Connection of Motors
The F C 300 is able to control several
parallel-connected motors. The total current
consumption of the motors must not exceed the
rated output current I
INV
for the FC 300.
Problems may arise at start and at low RPM values if m o tor sizes are widely different because small motors’
relatively hi gh ohmic resistance
in the stator calls for a higher voltage at start and at low RPM values.
The electronic thermal relay (ET
R) of the FC 300 cannot be used as motor protection for the individual motor
in syste m s with motors connected in parallel. Further motor protection must be provided, e .g. thermistors
in each motor or individual thermal relays. (Circuit breakers are not suitable as protection).
NB!:
When motors are connected
in parallel, parameter 1-29 Automatic motor
adaptation (AMA) cannot b e used.
For more information, see VLT AutomationDrive FC 300 Design Guide.
" Motor Thermal Protection
The electronic thermal relay in FC 300 has received the UL-approval for single motor protection,
when par. 1-90 Motor Thermal Protection is set for ETR Trip and par. 1-2 4 Motor current,
I
M,N
is set to the rated motor current (s ee motor name plate).
31
MG.33.A7.02 - VLT is a registered Danfoss trademark
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