Danfoss VLT Micro Drive FC 51 Series Programming Guide

4.3.3. 2-1* Brake Energy Function
Use the parameters in this group for selecting dynamic braking parameters.
2-10 Brake Function
Option: Function:
Resistor Brake:
The resistor brake limits voltage in the intermediate circuit when the motor acts as generator. Without brake
resistor, the frequency converter eventually trips.
The resistor brake consumes surplus energy resulting from motor braking. A frequency converter with brake
stops a motor faster than without a brake, which is used in many applications. Requires connection of external
brake resistor.
An alternative to the resistor brake is the AC brake.
NB!
Resistor brake is only functional in frequency converters with integrated dynamic brake. An
external resistor must be connected.
AC Brake:
The AC brake consumes surplus energy by creating power loss in the motor.
It is important to keep in mind that an increase in power loss causes motor temperature to rise.
[0]
*
Off No brake function.
[1] Resistor Brake Resistor brake is active.
[2] AC Brake AC brake is active.
2-11 Brake Resistor (Ohm)
Range: Function:
5  * [5 - 5000 ]
Set brake resistor value.
2-16 AC Brake, Max Current
Range: Function:
100.0 % * [0.0 - 150.0 %]
Enter max. permissible current for AC-braking to avoid overheating of motor.
100% equals motor current set in par. 1-24.
2-17 Over-Voltage Control
Option: Function:
Use Over-voltage Control (OVC) to reduce the risk of the frequency converter tripping due to an over voltage
on the DC link caused by generative power from the load.
An over-voltage occurs eg. if the ramp down time is set too short compared to the actual load inertia.
[0]
*
Disabled The OVC is not active/required.
[1] Enabled, not at stop OVC is running unless a stop signal is active.
[2] Enabled OVC is running, also when a stop signal is active.
NB!
If Resistor Brake has been chosen in par. 2-10
Brake Function the OVC is not active even though enabled in this parameter.
4.3.4. 2-2* Mechanical Brake
For hoisting applications an electro-magnetic brake is required. The brake is controlled by a relay, which releases the brake when activated.
The brake activates if frequency converter trips or a coast command is given. Furthermore, it activates when motor speed is ramped down below the
speed set in par. 2-22,
Active Brake Speed .
VLT
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Micro Drive FC 51 4. Parameter Descriptions
MG.02.C4.02 - VLT
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is a registered Danfoss trademark 23
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Danfoss VLT Micro Drive FC 51 Series Specifications

General

Brand	Danfoss
Model	VLT Micro Drive FC 51 Series
Category	Media Converter
Language	English