Danfoss VLT AutomationDrive FC 301 Programming Manual page 65

Parameter Descriptions
2-21 Activate Brake Speed [RPM]
Range: Function:
0 RPM [0 - 30000 Set the motor speed for activation of the
*
RPM] mechanical braking, when a stop condition
is present. The upper speed limit is
specified in parameter 4-53 Warning Speed
High.
2-22 Activate Brake Speed [Hz]
Range: Function:
0 Hz [0.0 - 5000.0 Hz] Set the motor frequency for activation
*
of the mechanical braking when a stop
condition is present.
2-23 Activate Brake Delay
Range: Function:
0.0 [0.0 - Enter the brake delay time of the coast after
s 5.0 s] ramp-down time. The shaft is held at 0 speed with
*
full holding torque. Ensure that the mechanical
braking has locked the load before the motor
enters coast mode. See Mechanical Brake Control
section in the design guide.
To adjust transition of the load to the mechanical
braking, set parameter 2-23 Activate Brake Delay
and parameter 2-24 Stop Delay.
Setting of brake delay parameters does not affect
the torque. The frequency converter does not
register that mechanical braking is holding the
load.
After setting parameter 2-23 Activate Brake Delay,
the torque drops to 0 after a few minutes. The
sudden torque change leads to movement and
noise.
2-24 Stop Delay
Range: Function:
0.0 [0.0 - Set the time interval from the moment when the
s 5.0 s] motor is stopped until the brake closes.
*
To adjust transition of the load to the mechanical
braking, set parameter 2-23 Activate Brake Delay
and parameter 2-24 Stop Delay.
This parameter is a part of the stop function.
MG33MO02
Programming Guide
2-25 Brake Release Time
Range:
0.20 s
*
3.3.4 Hoist Mechanical Brake
The hoist mechanical brake control supports the following
functions:
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Function:
[0.00 - 5.00 This value defines the time it takes for the
s] mechanical brake to open. This parameter
must act as a timeout when brake
feedback is activated.
2 channels for mechanical braking feedback to
offer further protection against unintended
behavior resulting from broken cable.
Monitoring of mechanical braking feedback
throughout the complete cycle. This helps protect
the mechanical brake, especially if more
frequency converters are connected to the same
shaft.
No ramp-up until feedback confirms that
mechanical brake is open.
Improved load control at stop. If the value of
parameter 2-23 Activate Brake Delay is too low,
Warning 22 Hoist mech. brake is activated and the
torque is not allowed to ramp down.
The transition when motor takes over the load
from the brake can be configured.
Parameter 2-28 Gain Boost Factor can be increased
to minimize the movement. To achieve smooth
transition, change the setting from the speed
control to the position control during the
changeover.
- Set parameter 2-28 Gain Boost Factor to
0 to enable position control during
parameter 2-02 DC Braking Time. This
enables parameter 2-30 Position P Start
Proportional Gain to
parameter 2-33 Speed PID Start Lowpass
Filter Time, which are PID parameters for
the position control.
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