2-12 Brake Power Limit (kW)
Range: Function:
To calculate parameter 2-12 Brake Power
Limit (kW), the following formula can be
used.
P
br, avg
W =
U
br
2
V × t
br
s
R
br
Ω × T
br
s
P
br,avg
is the average power dissipated in
the brake resistor. R
br
is the resistance of
the 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. For T4 units, the DC
voltage is 778 V, which can be reduced by
parameter 2-14 Brake voltage reduce.
NOTICE
If R
br
is not known or if T
br
is dierent
from 120 s, the practical approach is
to run the brake application, read out
parameter 16-33 Brake Energy Average,
and then enter this value + 20% in
parameter 2-12 Brake Power Limit
(kW).
2-14 Brake voltage reduce
Range: Function:
0 V* [ 0 - 0 V] Setting this parameter may change the brake
resistor (parameter 2-11 Brake Resistor (ohm)).
2-16 AC Brake, Max current
Range: Function:
100 %* [0 -
160 %]
Enter the maximum allowed current when
using AC brake to avoid overheating of
motor windings.
NOTICE
Parameter 2-16 AC Brake, Max current
has no eect when
parameter 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.
2-17 Over-voltage Control
Option: Function:
WARNING
PERSONAL INJURY AND EQUIPMENT
DAMAGE
Enabling OVC in hoisting applications
may lead to personal injuries and
equipment damage. Do not enable OVC
in such applications.
2-19 Over-voltage Gain
Range: Function:
100 %* [0 - 200 %] Select overvoltage gain.
2-20 Release Brake Current
Range: Function:
0 A* [0 -
100 A]
Set the motor current for release of the
mechanical brake when a start condition is
present. The default value is the maximum current
the inverter can provide for the particular power
size. The upper limit is specied in
parameter 16-37 Inv. Max. Current.
NOTICE
When mechanical brake control output is
selected, but no mechanical brake is
connected, the function does not work by
default setting due to too low motor
current.
2-22 Activate Brake Speed [Hz]
Range: Function:
0 Hz* [0 - 400 Hz] Set the motor frequency for activation of
the mechanical brake when a stop
condition is present.
2-23 Activate Brake Delay
Range: Function:
0 s* [0 - 5 s]
Parameter Descriptions Programming Guide
MG07C102 Danfoss A/S © 12/2015 All rights reserved. 41
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