Mechanical Brake; Over-Voltage Control; Release Brake Current; Activating Mechanical Brake - Danfoss VLT FC 51 Series Programming Manual

VLT Micro Drive FC 51

2-17 Over-Voltage Control

Option:
*
[0]
[1]
[2]

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,
Speed

2-20 Release Brake Current

Range:
0.00 A

2-22 Activating Mechanical Brake

Range:
*
0 Hz
Function:
Use Over-voltage Control (OVC) to reduce the risk of the fre-
quency 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.
Disabled The OVC is not active/required.
Enabled, not at stop OVC is running unless a stop signal is active.
Enabled OVC is running, also when a stop signal is active.
NB!
If Resistor Brake has been chosen in par. 2-10
even though enabled in this parameter.
.
Function:
*
[0.00 - 100 A] Select motor current at which mechanical brake releases.
Function:
If the motor is stopped using ramp, the mechanical brake is ac-
tivated when motor speed is less than
Motor is ramped down to stop in the following situations:
[0 - 400 Hz] Select motor speed at which mechanical brake activates when
ramping down.
Mechanical brake automatically activates if frequency converter
trips or reports an alarm.
MG.02.C2.02 - VLT ® is a registered Danfoss trademark
Brake Function
If start delay time has passed, and motor current
Release brake current
is below
verter trips.
• A start command is removed (stand by)
• A stop command is activated
• Quick-stop is activated (Q-stop ramp is used)
4. Parameter Descriptions
the OVC is not active
Active Brake
, frequency con-
Active Brake Speed
.
4
29