Danfoss VLT AutomationDrive EZ FC 321 Programming Manual page 99

VLT® AutomationDrive EZ FC 321
Programming Guide
Op- Name Description
tion
[0] Off No brake resistor installed.
[1] Resistor A brake resistor is incorporated in the system for dissipation of surplus brake energy as heat. Connecting a
brake brake resistor allows a higher DC-link voltage during braking (generating operation). The resistor brake
function is only active in drives with an integral dynamic brake.
[2] AC brake Improves braking without using a brake resistor. This parameter controls an overmagnetization of the mo-
tor when running with a generatoric load. This function can improve the OVC function. Increasing the elec-
trical losses in the motor allows the OVC function to increase the braking torque without exceeding the
overvoltage limit.
The AC brake is not as efficient as dynamic braking with resistor. AC brake is for VVC
and closed loop.
Parameter 2-11 Brake Resistor (ohm)
Table 154: Parameter 2-11 Brake Resistor (ohm)
2-11 Brake Resistor (ohm)
Default value: Size related
Conversion index: 0
Set the brake resistor value in Ω. This value is used for monitoring the power to the brake resistor in parameter 2-13 Brake Power
Monitoring. This parameter is only active in drives 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).
Parameter 2-12 Brake Power Limit (kW)
Table 155: Parameter 2-12 Brake Power Limit (kW)
2-12 Brake Power Limit (kW)
Default value: Size related
Conversion index: 0
Parameter 2-12 Brake Power Limit (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 s
br br
P W =
br, avg
R Ω × T s
br br
P is the average power dissipated in the brake resistor, R
br,avg
within the 120 s period, T . U
br
• T2 units: 390 V
• T5 units: 810 V
• T6 units: 943 V/1099 V for D enclosures
• T7 units: 1099 V
If R is not known, or if T is different from 120 s, the practical approach is to run the brake application, read parameter 16-33
br br
Brake Energy Average and then enter this + 20% in parameter 2-12 Brake Power Limit (kW).
Danfoss A/S © 2021.08
Parameter type: Range, 0 - 65535 Ohm
Data type: Uint16
Parameter type: Range, 0.001 - 2000.000 kW
Data type: Uint32
is the DC voltage where the brake resistor is active. This depends on the unit as follows:
br
N O T I C E
N O T I C E
is the resistance of the brake resistor. t
br
Parameter Descriptions
+
mode in both open
Setup: All setups
Change during operation: True
Setup: All setups
Change during operation: True
is the active braking time
br
AU373327181955en-000101 / 130R1208 | 99