Danfoss VLT Brake Resistor MCE 101 Design Manual page 26

Programming
16-33 Brake Energy /2 min
Range:
0 kW [0 - 10000
*
kW]
30-81 Brake Resistor (ohm)
Range:
Size [ 0.01 -
5 5
related 65535.00
*
Ohm]
24
Design Guide
Function:
View the brake power transmitted to an
external brake resistor. The mean power is
calculated on an average level based on
the selected time period within 2-13 Brake
Power Monitoring.
Function:
Set the brake resistor value in Ω. This
value is used for monitoring the
power to the brake resistor in
2-13 Brake Power Monitoring. This
parameter is only active in frequency
converters with an integral dynamic
brake.
Danfoss A/S © Rev. 05/2014 All rights reserved.
5.4 Parameters for VLT
FC 360
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 brake resistor 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 overmagnetisation 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 braking
torque without exceeding the voltage 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
Size [ 0 -
related 65535 value is used for monitoring the power to
*
Ohm] the brake resistor. Parameter 2-11 Brake
Resistor (ohm) is only active in frequency
converters with an integral dynamic brake.
Use this parameter for values without
decimals.
2-12 Brake Power Limit (kW)
Range: Function:
Size [0.001 Parameter 2-12 Brake Power Limit (kW) is the
related - 2000 expected average power dissipated in the
*
kW] brake resistor over a period of 120 s. It is
used as the monitoring limit for 16-33 Brake
Energy /2 min 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 br,avg W =
P is the average power dissipated in the
br,avg
brake resistor, R
®
AutomationDrive
+
mode in both open
U br 2 V × t br s
R br Ω × T br s
is the resistance of the
br
MG90O202