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4.6 Parameter Group 4-** Special Functions
400
Brake function
Value:
Off (off)
[0]
Resistor brake
(Resistor)
[1]
AC brake (AC Brake)
[4]
Function:
Resistor brake
[1] is selected if the frequency converter has a brake re-
sistor connected to terminals 81, 82. A higher intermediate circuit voltage
is permitted during braking (generated operation) when a brake resistor
is connected.
AC brake
[4] can be selected to improve braking without using brake
resistors. Please note that
AC brake
[4] is not as effective as
Resistor
brake
[1].
Description of choice:
Select
Resistor brake
[1] if a brake resistor is connected.
Select
AC brake
[4] if short-term generated loads occur. See parameter
144
Gain AC brake
to set the brake.
NB!
A change of selection will not become active until the
mains voltage has been disconnected and reconnec-
ted.
405
Reset function
Value:
Manual reset (manual reset)
[0]
Automatic reset x 1
(AUTOMATIC x 1)
[1]
Automatic reset x 3
(AUTOMATIC x 3)
[3]
Automatic reset x 10
(AUTOMATIC x 10)
[10]
Reset at power-up
(RESET AT POWER UP)
[11]
Function:
This parameter makes it possible to select whether reset and restart after
a trip are to be manual or whether the adjustable frequency drive is to
be reset and restarted automatically. Furthermore, it is possible to select
the number of times a restart is to be attempted. The time between each
attempt is set in parameter 406
Automatic restart time
.
Description of choice:
If
Manual reset
[0] is selected, reset is to be carried out via the [STOP/
RESET] key, a digital input or serial communication. If the adjustable fre-
quency drive is to carry out an automatic reset and restart after a trip,
select data value [1], [3] or [10].
If
Reset at power-up
[11] is selected, the adjustable frequency drive will
carry out a reset if there has been a fault in connection with the mains
failure.
The motor may start without warning.
406
Automatic restart time
Value:
0 - 10 sec.
5 sec.
Function:
This parameter allows setting of the time from tripping until the automatic
reset function begins. It is assumed that automatic reset has been se-
lected in parameter 405
Reset function
.
Description of choice:
Set the required time.
409
Trip delay overcurrent, I
LIM
Value:
0 - 60 sec. (61=OFF)
OFF
Function:
When the adjustable frequency drive registers that the output current has
reached the current limit I
LIM
(parameter 221
Current limit
) and remains
there for the preset time, it is disconnected. Can be used to protect the
application, like the ETR will protect the motor if selected.
Description of choice:
Select how long the adjustable frequency drive should maintain the out-
put current at the current limit I
LIM
before it disconnects. At OFF param-
eter 409
Trip delay overcurrent, I
LIM
is not working, i.e. disconnection
will not take place.
411
Switching frequency
Value:
3000 - 14000 Hz
4500 Hz
Function:
The set value determines the switching frequency of the inverter. If the
switching frequency is changed, this may help to minimise possible
acoustic noise from the motor.
NB!
The output frequency of the frequency converter can
never assume a value higher than 1/10 of the switch-
ing frequency.
Description of choice:
When the motor is running, the switching frequency is adjusted in pa-
rameter 411
Switching frequency
until the frequency has been obtained
at which the motor is as low-noise as possible.
NB!
The switching frequency is reduced automatically as a
function of the load. See
Temperature-Dependent
Switching Frequency
under
Special Conditions
.
413
Overmodulation function
Value:
Off (off)
[0]
VLT
®
Decentral FCD 300 Design Guide
4 Programming
MG.90.S1.02 - VLT
®
is a registered Danfoss trademark
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