VLT
®
6000 HVAC Series
Function:
The motor preheater ensures that no condensate
develops in the motor at stop. This function can also
be used to evaporate condensed water in the motor.
The motor preheater is only active during stop.
Description of choice:
Select
Disable
[0] if this function is not required. Select
Enable
[1] to activate motor preheating. The DC current
is set in parameter 113
Motor preheater DC current
.
113 Motor preheater DC current
(PREHEAT DC-CURR.)
Value:
0 - 100 %
✭
50 %
The maximum value depends on the rated motor
current, parameter 105
Motor current, I
M,N
.
Function:
The motor can be preheated at stop by means of a DC
current to prevent moisture from entering the motor.
VLT 6152-6602, 380-460 V and VLT 6102-6652,
525-600 V work with a reduced DC current. The level
can, depending on motor selection, be down to 80%.
Description of choice:
The motor can be preheated by means of a DC
current. At 0%, the function is inactive; at a value
higher than 0%, a DC current will be supplied to
the motor at stop (0 Hz). This function can also
be used to generate a holding torque.
If too high a DC current is supplied for too
long, the motor can be damaged.
■
DC braking
In DC braking, the motor receives a DC current
that brings the shaft to a halt. Parameter 114
DC
braking current
, decides the DC braking current as
a percentage of the rated motor current I
M,N
.
In parameter 115
DC braking time
, the DC braking
time is selected, and in parameter 116
DC brake
cut-in frequency
, the frequency is selected at
which DC braking becomes active.
If terminal 19 or 27 (parameter 303/304
Digital input
) has
been programmed to
DC braking inverse
and shifts from
logic "1" to logic "0", the DC braking will be activated.
When the start signal on terminal 18 changes
from logic "1" to logic "0", the DC braking will be
activated when the output frequency becomes lower
than the brake coupling frequency.
NB!:
The DC brake is not to be used if the inertia
of the motor shaft is more than 20 times
the inertia of the motor itself.
114 DC braking current
(DC BRAKE CURRENT)
Value:
✭
50 %
The maximum value depends on the rated
motor current. If the DC braking current is
active, the frequency converter has a switching
frequency of 4 kHz.
Function:
This parameter is used for setting the DC braking
current that is activated upon a stop when the DC
brake frequency set in parameter 116,
DC brake
cut-in frequency
has been reached, or if DC brake
inverse is active via terminal 27 or via the serial
communication port. The DC braking current will
be active for the duration of the DC braking time
set in parameter 115
DC braking time
.
VLT 6152-6602, 380-460 V and VLT 6102-6652,
525-600 V work with a reduced DC current. The level
can, depending on motor selection, be down to 80%.
Description of choice:
To be set as a percentage value of the rated motor
current I
M,N
set in parameter 105 Motor current, I
VLT,N
.
100% DC braking current corresponds to I
M,N
.
Make sure not to supply too high a braking
current for too long.The motor will be
damaged because of mechanical overload
or the heat generated in the motor.
115 DC braking time
(DC BRAKE TIME)
Value:
0.0 - 60.0 sec.
✭
10 sec.
Function:
This parameter is for setting the DC braking time
for which the DC braking current (parameter
113) is to be active.
Description of choice:
Set the desired time.
✭
= factory setting. () = display text [] = value for use in communication via serial communication port
MG.61.A5.02 - VLT is a registered Danfoss trademark
90