VLT® 5000 Crane
■
Application Functions
400 BRAKE FUNCTION
Value:
Off (OFF)
[0]
✭
Resistor brake (RESISTOR)
[1]
Function:
The factory setting is
On
[1] for VLT
5052-5062 400-500 V.
Resistor brake
[1] is used for programming the
frequency converter for connection of a brake
resistor. The connection of a brake resistor
allows a higher intermediate circuit voltage during
braking (generating operation).
The Resistor brake
[1] function is only active in units
with an integral dynamic brake (SB and EB units).
Description of choice:
Select Resistor brake
[1] if a brake resistor
is part of the system.
401 BRAKE RES. (OHM)
Value:
Depends on the unit
✭
Depends on the unit
Function:
This parameter gives the ohmic value of the brake
resistor. This value is used for monitoring the
power to the brake resistor provided this function
has been selected in parameter 403.
402 BR.POWER LIM.KW
Value:
Depends on the unit
✭
Depends on the unit
Function:
This parameter gives the monitoring limit of the
power transmitted to the brake resistor.
Description of choice:
The monitoring limit is determined as a product of
the maximum duty cycle (120 sec.) that will occur
and the maximum power of the brake resistor at that
duty cycle according to the following formula.
For 400 - 500 V units: P =
403 POWER MONITORING
Value:
Off (OFF)
[0]
✭
Warning (WARNING)
[1]
Trip (TRIP)
[2]
Function:
This parameter allows monitoring of the power
transmitted to the brake resistor. The power is
calculated on the basis of the resistor ohm value
(parameter 401), the intermediate circuit voltage and
the resistor running time. If the power transmitted
over 120 sec. exceeds 100% of the monitoring limit
(parameter 402) and
Warning
[1] has been selected,
a warning will come up on the display. The warning
will disappear if the power goes below 80%. If the
calculated power exceeds 100% of the monitoring limit
and
Trip
[2] has been selected in parameter 403
Power
monitoring
, the VLT frequency converter will cut out
while giving an alarm. If power monitoring has been
selected as
Off
[0] or
Warning
[1], the brake function
will remain active, even if the monitoring limit has been
exceeded. This may lead to thermal overload of the
resistor. It is also possible to have a warning via the
relay/digital outputs. The typical measuring accuracy
of the power monitoring depends on the accuracy of
the resistor ohmic value (better than ± 20%).
Description of choice:
Select whether this function is to be active (
Warning/Alarm
) or inactive (
Off
).
404 BRAKE TEST
Value:
✭
Off (OFF)
[0]
Warning (WARNING)
[1]
Trip (TRIP)
[2]
Function:
In this parameter a testing and monitoring function
can be integrated which will give a warning or an
alarm. On power-up it will be tested whether the brake
resistor is disconnected. The test of whether the brake
resistor is disconnected is carried out during braking,
while the test of whether the IGBT is disconnected
is carried out when there is no braking. A warning
or trip disconnects the brake function.
The testing sequence is as follows:
1. If the intermediate circuit voltage is higher than the
brake starting voltage, discontinue the brake check.
2. If the intermediate circuit voltage is unstable,
discontinue the brake check.
3. Carry out a brake test.
✭
= factory setting. () = display text [] = value for use in communication via serial communication port
MG.50.N4.02 - VLT is a registered Danfoss trademark
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