2-16 AC Brake Max. Current
Range: Function:
100%
*
[0 - 1000%] Enter the maximum permissible current when using AC brake to
avoid overheating of motor windings. The AC brake function is
available in Flux mode only (FC 302 only).
2-17 Over-voltage Control
Option: Function:
Over-voltage control (OVC) reduces the risk of the drive tripping
due to an over voltage on the DC link caused by generative
power from the load.
[0]
*
Disabled No OVC required.
[1] Enabled (not at stop) Activates OVC except when using a stop signal to stop the fre-
quency converter.
[2] Enabled Activates OVC.
NB!
OVC must not be enabled in hoisting applications.
2.5.4. 2-2* Mechanical Brake
Parameters for controlling operation of an electro-magnetic (mechanical) brake, typically required
in hoisting applications.
To control a mechanical brake, a relay output (relay 01 or relay 02) or a programmed digital output
(terminal 27 or 29) is required. Normally this output must be closed during periods when the drive
is unable to ‘hold’ the motor, e.g. due to an excessive load. Select
Mechanical Brake Control
[32]
for applications with an electro-magnetic brake in par. 5-40
Function Relay
, par. 5-30
Terminal
27 Digital Output
, or par. 5-31
Terminal 29 Digital Output
. When selecting
Mechanical brake con-
trol
[32], the mechanical brake is closed from start up until the output current is above the level
selected in par. 2-20
Release Brake Current
. During stop, the mechanical brake activates when
the speed falls below the level specified in par. 2-21
Activate Brake Speed [RPM]
. If the frequency
converter enters an alarm condition or an over-current or over-voltage situation, the mechanical
brake immediately cuts in. This is also the case during safe stop.
NB!
Protection mode and trip delay features (par. 14-25 and 14-26) may delay the ac-
tivation of the mechanical brake in an alarm condition. These features must be
disabled in hoisting applications.
FC 300 Programming Guide 2. How to Programme
MG.33.M2.02 - VLT
®
is a registered Danfoss trademark
67
2
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