Brake Energy Funct; Maximum Reference; Brake Resistor (Ohm); Brake Power Monitoring - Danfoss VLT AutomationDrive FC 302 Programming Manual

Parameter Descriptions

2-05 Maximum Reference

Range: Function:
unit matches the option selected in
parameter 1-00 Configuration Mode
and the unit in
parameter 3-01 Reference/Feedback
Unit.
2-06 Parking Current
Range: Function:
50 % [ 0 - Set current as percentage of rated motor
*
1000 %] current, parameter 1-24 Motor Current. Is
used when enabled in parameter 1-70 Start
Mode.
2-07 Parking Time
Range: Function:
3 s [0.1 - 60 s] Set the duration of the parking current set in
*
parameter 2-06 Parking Current, once activated.

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: Function:
[0] Off No brake resistor is installed.
[1] Resistor A brake resistor is incorporated in the system, for
brake 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.
[2] AC 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
and closed loop.

2-11 Brake Resistor (ohm)

Range: Function:
Set the brake resistor value in Ω. This value
Size [ 0 -
related 65535
is used for monitoring the power to the
*
Ohm] brake resistor in parameter 2-13 Brake Power
MG33MP02
Programming Guide
+
mode in both open
Danfoss A/S © 10/2018 All rights reserved.
2-11 Brake Resistor (ohm)
Range: Function:
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).
2-12 Brake Power Limit (kW)
Range: Function:
Size [ 0.001 - Parameter 2-12 Brake Power Limit (kW) is
related 2000.000 the expected average power dissipated in
*
kW] 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.
P W =
br, avg
P is the average power dissipated in
br,avg
the brake resistor, R
the brake resistor. t
breaking time within the 120 s period,
T .
br
U is the DC voltage where the brake
br
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).

2-13 Brake Power Monitoring

Option: Function:
This parameter is only active in frequency
converters with a brake.
This parameter enables monitoring of the
power to the brake resistor. The power is
calculated based on the resistance
2
U V × t s
br br
R Ω × T s
br br
is the resistance of
br
is the active
br
is
br
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