FC 300 Instruction Manual
How to Install
" ControlofMechanicalBrake
In hoisting/lowering applications, you need to be able to control a n electromechanical b rake.
• Control the brake using any relay output or digital output (terminal 27 or 29).
• Keep the output closed (voltage-free) as long as the adjustable frequency drive 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 electromechanical brake.
• The brake is released when the motor current exceeds the preset 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 adjus table frequency drive carries out a stop command.
If the adjustable f requency drive is in alarm mode or in an overvoltage sit uation, the
mechanical brake immediately cuts in.
" Parallel connection o f 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 motor sizes are widely different because small mo tors’
relatively high ohmic resistance in the sta tor calls for a higher voltage at start and at low rpm values.
The electronic the rmal relay (ETR) of the FC 300 cannot be used as motor protection for the individual motor
in syste ms 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).
NOTE
When motors are connected in parallel, parameter 1-02 Automatic motor adaptation (AMA) cannot
be used and Parameter 1-01 Torque characteristics must be set to Special motor characteris tics.
For more information, see VLT AutomationDrive FC 300 Design Guide.
" Thermal motor protection
The electronic thermal relay in FC 3 00 has received the UL-approval for single motor protection,
when parameter 1-26 Motor thermal protection is set for ETR Trip and p arameter 1-23 Motor
current, I
M, N
is se t to the rated motor current (see motor nameplate).
33
MG.33.A4.22 - VLT is a registered Danfoss trademark
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