2-12 Brake Power Limit (kW)
Range:
Function:
brake resistor. t
br
is the active breaking time
within the 120 s period, T
br
.
U
br
is the DC voltage where the brake
resistor is active. This depends on the unit
as follows:
T4 units: 778 V
NOTICE
If R
br
is not known or if T
br
is different
from 120 s, the practical approach is
to run the brake application, readout
16-33 Brake Energy /2 min
and then
enter this + 20% in
2-12 Brake Power
Limit (kW)
.
2-16 AC Brake, Max current
Range:
Function:
100 %
*
[0 - 160
%]
Enter the maximum permissible current
when using AC brake to avoid overheating
of motor windings.
NOTICE
Parameter 2-16 AC Brake, Max current
has no effect when
1-10 Motor
Construction
is set to
[1] PM, non-
salient SPM
.
2-17 Over-voltage Control
Option:
Function:
Overvoltage control (OVC) reduces the risk of
the frequency converter tripping due to an
overvoltage on the DC-link caused by
generative power from the load.
[0]
*
Disabled
No OVC required.
[1]
Enabled
(not at
stop)
Activates OVC except when using a stop signal
to stop the frequency converter.
[2]
Enabled
Activates OVC
WARNING
Do NOT enable OVC in hoisting
applications.
5.5 Parameters for VLT
®
2800
126 DC brake time
Range:
Function:
10 sec
*
[0 - 60 sec.] The DC brake time is set at which
parameter 132
DC brake voltage
is to be
active.
127 DC brake cut-in frequency
Range:
Function:
0.00 OFF
*
[0.0 (OFF) -
par. 202]
Set the DC brake cut-in frequency at
which the DC brake is to be
activated in connection with a stop
command.
132 DC brake voltage
Range:
Function:
0%
*
[0 - 100% of
max. DC
brake
voltage]
Set the DC brake voltage to be activated at
stop when the DC brake frequency set in
parameter
127 DC brake cut-in frequency
is
reached, or if
DC braking inverse
is active via
a digital input or via serial communication.
Subsequently, the DC brake voltage is active
for the time set in parameter
126 DC brake
time
.
400 Brake function
Option:
Function:
[0] Off
[1] Resistor
brake
Select
[1] Resistor brake
if the frequency
converter has an integral brake transistor, and a
brake resistor is connected to terminals 81, 82.
A higher DC-link voltage is permitted during
braking (generated operation) when a brake
resistor is connected.
[4] AC brake
Select
[4] AC brake
to improve braking without
using brake resistors. Note that
[4] AC brake
is
not as effective as
[1] Resistor brake
.
[5] Load
sharing
NOTICE
Disconnected and reconnect mains voltage to activate a
change of selection.
Programming
Design Guide
MG90O202
Danfoss A/S © Rev. 05/2014 All rights reserved.
25
5
5
Содержание VLT Brake Resistor MCE 101
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