2-15 Brake Check
Option:
Function:
3.
If the DC link ripple amplitude while
braking is lower than the DC link ripple
amplitude before b 1%:
Brake
check has failed by returning a warning or
alarm.
4.
If the DC link ripple amplitude while
braking is higher than the DC link ripple
amplitude before b 1%:
Brake
check is OK.
[0]
*
Off
Monitors brake resistor and brake IGBT for a short-
circuit during operation. If a short-circuit occurs,
warning 25 appears.
[1]
Warning
Monitors brake resistor and brake IGBT for a short-
circuit, and runs a test for brake resistor
disconnection during power-up.
[2]
Trip
Monitors for a short-circuit or disconnection of the
brake resistor, or a short-circuit of the brake IGBT.
If a fault occurs, the adjustable frequency drive
cuts out while displaying an alarm (trip locked).
[3]
Stop and
trip
Monitors for a short-circuit or disconnection of the
brake resistor, or a short-circuit of the brake IGBT.
If a fault occurs, the adjustable frequency drive
ramps down to coast and then trips. A trip lock
alarm is displayed (e.g., warning 25, 27 or 28).
[4]
AC brake
Monitors for a short-circuit or disconnection of the
brake resistor, or a short-circuit of the brake IGBT.
If a fault occurs, the adjustable frequency drive
performs a controlled ramp-down. This option is
available for FC 302 only.
[5]
Trip Lock
NOTE!
Remove a warning arising in connection with
Off
[0] or
Warning
[1] by cycling the line power supply. The fault must
be corrected first. For
Off
[0] or
Warning
[1], the adjustable
frequency drive keeps running even if a fault is located.
This parameter is only active in adjustable frequency drives
with an integral dynamic brake.
2-16 AC brake Max. Current
Range:
Function:
100.0 %
*
[Application
dependant]
Enter the maximum permissible
current when using AC brake to
avoid overheating 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 adjustable frequency drive tripping
due to overvoltage 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 adjustable frequency drive.
[2]
Enabled
Activates OVC.
NOTE!
OVC must not be enabled in hoisting applications.
2-18 Brake Check Condition
Range:
Function:
[0]
*
At Power-up
Brake check will be performed at power-up
[1]
After Coast Sit. Brake check will be performed after coast
situations
2-19 Over-voltage Gain
Range:
Function:
100 %
*
[0 - 200 %]
Select overvoltage gain.
3.4.3 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 adjustable frequency drive is unable to
‘hold’ the motor, e.g., due to an excessive load. Select
Mechanical Brake Control
[32] for applications with an
5-30 Terminal
27 Digital Output
, or
5-31 Terminal 29 digital Output
. When
selecting
Mechanical brake control
[32], the mechanical brake
is closed from start up until the output current is above the
level selected in
. During stop, the
mechanical brake activates when the speed falls below the
level specified in
2-21 Activate Brake Speed [RPM]
. If the
adjustable frequency drive enters an alarm condition or an
overcurrent or overvoltage situation, the mechanical brake
immediately cuts in. This is also the case during safe stop.
Parameter Descriptions
FC 300 Programming Guide
MG.33.MA.22 - VLT
®
is a registered Danfoss trademark
3-29
3
3
