Closed-Loop Mechanical Brake Control/Hoist Mechanical Brake - Danfoss VLT AutomationDrive FC 301 Series Design Manual

Product Features

4.2.13 Closed-loop Mechanical Brake Control/Hoist Mechanical Brake

The hoist mechanical break control supports the following functions:
•
Two channels for mechanical brake feedback to offer further protection against unintended behavior resulting
from broken cable.
•
Monitoring of mechanical brake feedback throughout the complete cycle. This helps protect the mechanical brake
4 4
- especially if more adjustable frequency drives are connected to the same shaft.
•
No ramp up until feedback confirms mechanical brake is open.
•
Improved load control at stop. If 2-23 Activate Brake Delay is set too short, W22 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. 2-28 Gain Boost Factor can be
increased to minimize the movement. For very smooth transition, change the setting from the speed control to
the position control during the change-over.
MotorSpeed
Torqueref.
Relay
GainBoost
Mech.Brake
Figure 4.3 Brake release sequence for hoist mechanical brake control. This brake control is available in FLUX with motor feedback
only, available for asynchronous and non-salient PM motors.
2-26 Torque Ref to 2-33 Speed PID Start Lowpass Filter Time are only available for the hoist mechanical brake control (FLUX
with motor feedback). 2-30 Position P Start Proportional Gain to 2-33 Speed PID Start Lowpass Filter Time can be set up for
very smooth transition change from speed control to position control during 2-25 Brake Release Time - the time when the
load is transferred from the mechanical brake to the adjustable frequency drive.
2-30 Position P Start Proportional Gain to 2-33 Speed PID Start Lowpass Filter Time are activated when 2-28 Gain Boost Factor is
set to 0. See Figure 4.3 for more information.
NOTICE!
For an example of advanced mechanical brake control for hoisting applications, see chapter 10 Application Examples.
46
•
Set 2-28 Gain Boost Factor to 0 to enable Position Control during 2-25 Brake Release Time. This enables
parameters 2-30 Position P Start Proportional Gain to 2-33 Speed PID Start Lowpass Filter Time which are PID
parameters for the Position Control.
II
I
Brake
Premag Torque Ramp
Release
Time
Time
p. 2-27
p. 2-25
Torque Ref. 2-26
Gain Boost Factor
p. 2-28
1 2 3
Design Guide
Ramp 1 upp. 3-41 Ramp 1 downp. 3-42
Rev. 2014-04-04 All rights reserved.
Stop Activate
Delay Brake
p. 2-24 Delay
p. 2-23
MG33BF22