[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 frequency converter performs a controlled ramp down. This option is available for FC 302 only.
NB!
NB!: Remove a warning arising in connection with
Off
[0] or
Warning
[1] by cycling the mains supply. The fault must be corrected first.
For
Off
[0] or
Warning
[1], the frequency converter keeps running even if a fault is located.
This parameter is only active in frequency converters with an integral dynamic brake.
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 frequency converter 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 frequency 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 frequency converter 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 control
[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 activation of the mechanical brake in an alarm condition.
These features must be disabled in hoisting applications.
2. How to Programme
FC 300 Programming Guide
58
MG.33.M3.02 - VLT
®
is a registered Danfoss trademark
2