3.9. Additional Connections
3.9.1. Mechanical Brake Control
In hoisting/lowering applications, it is necessary to be able to control an electro-
mechanical brake:
•
Control the brake using 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-me-
chanical 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 frequency converter carries out a stop command.
If the frequency converter is in alarm mode or in an over-voltage situation, the mechanical brake
immediately cuts in.
3.9.2. Parallel Connection of Motors
The frequency converter can control several
parallel-connected motors. The total current
consumption of the motors must not exceed
the rated output current I
M,N
for the frequency
converter.
NB!
Installations with cables con-
nected in a common joint as in
the illustration below, is only
recommended for short cable
lengths.
NB!
When motors are connected in
parallel, par. 1-29
Automatic
Motor Adaptation (AMA)
cannot
be used.
NB!
The electronic thermal relay
(ETR) of the frequency convert-
er cannot be used as motor pro-
tection for the individual motor
of systems with parallel-connec-
ted motors. Provide further mo-
tor protection by e.g. thermis-
tors in each motor or individual
thermal relays (circuit breakers
are not suitable as protection).
VLT
®
Automation Drive FC 300
Operating Instructions High Power
3. How to Install
MG.33.U1.02 - VLT
®
is a registered Danfoss trademark
69
3