Danfoss VT2800 Series Design Manual page 77

Function:
This parameter can be set so that the internal fan is
automatically switched on and off. You can also set
the internal fan to be permanently switched on or off.
Description of choice:
If Automatic [0] is selected, the internal fan is switched
on or off depending on the ambient temperature
and the loading of the frequency converter.
If Always switched on [1] Always switched
off [2] are selected, the internal fan will be
permanently switched on or off.
NB!:
If Always switched off [2] is selected in
combination with high switch frequency,
long motor cables or high output power, the
frequency converter's life span is reduced.
144 Gain AC brake
(GAIN AC BRAKE)
Value:
1.00 - 1.50
Function:
This parameter is used to set the AC brake. Using par.
144 it is possible to adjust the size of the generator
torque that can be applied to the motor without the
intermediate circuit voltage exceeding the warning level.
Description of choice:
The value is increased if a greater possible brake
torque is required. If 1.0 is selected, this corresponds
to the AC brake being inacti v e.
NB!:
If the value in par. 144 is increased, the
motor current will simultaneously increase
significantly when generator loads are applied.
The parameter should therefore only be changed if
it is guaranteed during measurement that the motor
current in all operating situations will never exceed the
maximum permitted current in the motor. Please note:
that the current cannot be read out from the display.
146 Reset voltage vector
(RESET VECTOR)
Value:
*Off (OFF)
Reset (RESET)
= factory setting. () = display text [] = value for use in communication via serial communication port
MG.28.E9.02 - VLT is a registered Danfoss trademark
Function:
When the voltage vector is reset it is set to the same
starting point each time a new process commences.
Description of choice:
Select reset (1) when running unique processes each
time they arise. This will enable repetiti v e precision
when stopping to be improved. Select Off (0) for
example for lifting/lowering operations or synchronous
motors. It is an advantage that the motor and the
frequency converter are always synchronized.
1.30
[0]
[1]
®
VLT 2800 Series
77