Danfoss VLT AutomationDrive FC 301 Programming Manual page 82

Parameter Descriptions
2-06 Parking Current
Range:
50 %
*
3 3
2-07 Parking Time
Range:
3 s
*
3.3.2 2-1* Brake Energy Funct.
Parameter group for selecting dynamic brake parameters.
Only valid for frequency converters with brake chopper.
2-10 Brake Function
Option:
[0] Off
[1] Resistor brake
[2] AC brake
2-11 Brake Resistor (ohm)
Range:
Size
related Ohm]
*
80
Function:
[ 0 - 1000 %] Set current as percentage of rated
motor current, parameter 1-24 Motor
Current. Is used when enabled in
parameter 1-70 Start Mode.
Function:
[0.1 - 60 s] Set the duration of the parking
current set in
parameter 2-06 Parking Current, once
activated.
Function:
No brake resistor is installed.
A brake resistor is incorporated in
the system for dissipation of surplus
brake energy as heat. Connecting a
brake resistor allows a higher DC-
link voltage during braking
(generating operation). The resistor
brake function is only active in
frequency converters with an
integral dynamic brake.
Improves braking without using a
brake resistor. This parameter
controls an overmagnetization of
the motor when running with a
generatoric load. This function can
improve the OVC function.
Increasing the electrical losses in
the motor allows the OVC function
to increase the braking torque
without exceeding the overvoltage
limit.
NOTICE
The AC brake is not as efficient
as dynamic braking with
resistor.
AC brake is for VVC
both open and closed loop.
Function:
Set the brake resistor value in Ω.
[ 0 - 65535
This value is used for monitoring
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®
VLT AutomationDrive FC 301/302
2-11 Brake Resistor (ohm)
Range:
2-12 Brake Power Limit (kW)
Range:
Size
related
*
+
mode in
Function:
the power to the brake resistor in
parameter 2-13 Brake Power
Monitoring. This parameter is only
active in frequency converters with
an integral dynamic brake.
Use this parameter for values
without decimals. For a selection
with 2 decimals, use
parameter 30-81 Brake Resistor
(ohm).
Function:
[ 0.001 - Parameter 2-12 Brake Power Limit
2000.000 kW] (kW) is the expected average power
dissipated in the brake resistor over
a period of 120 s. It is used as the
monitoring limit for
parameter 16-33 Brake Energy
Average and thereby specifies when
a warning/alarm is to be given.
To calculate parameter 2-12 Brake
Power Limit (kW), the following
formula can be used.
2
U V × t
br
P W =
br, avg
R Ω × T
br
P is the average power
br,avg
dissipated in the brake resistor, R
is the resistance of the brake
resistor. t is the active breaking
br
time within the 120 s period, T
U is the DC voltage where the
br
brake resistor is active. This
depends on the unit as follows:
T2 units: 390 V
T4 units: 810 V
T5 units: 810 V
T6 units: 943 V/1099 V for D – F
frames
T7 units: 1099 V
NOTICE
If R is not known, or if T
br
different from 120 s, the
practical approach is to run
the brake application, read
parameter 16-33 Brake Energy
Average and then enter this
+ 20% in parameter 2-12 Brake
Power Limit (kW).
s
br
s
br
br
.
br
is
br
M0013101