Danfoss FC 300 Design Manual page 148

FC 300 Design Guide
tude before braking + 1 %. Brake check
failed, return a warning or alarm.
4. If the DC link ripple amplitude while brak-
ing is higher than the DC link ripple am-
plitude before braking + 1 %. Brake check
OK.
Select Off [0] to monitor the brake resistor and
the brake IGBT for a short-circuit during opera-
tion. If a short-circuit occurs, a warning appears.
Select Warning [1] to monitor the brake resistor
and brake IGBT for a short-circuit, and to run a
test for brake resistor disconnection during pow-
er-up.
Select Trip [2], to monitor for a short-circuit or
disconnection of the brake resistor, or a short-cir-
cuit of the brake IGBT. If a fault occurs the fre-
quency converter cuts out while displaying an
alarm (trip locked).
Select Stop and Trip [3] to monitor 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 ramps down to coast and
then trips. A trip lock alarm is displayed.
Select AC Brake [4] to monitor 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 con-
nection 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 convert-
er keeps running even if a fault is lo-
cated.
This parameter is only active in frequency con-
verters with an integral dynamic brake.
2-16 AC Brake Max. Current
Value:
0 - 1000%
Function:
Enter the maximum permissible current when us-
ing AC brake to avoid overheating of motor wind-
ings. The AC brake function is available in Flux
mode only (FC 302 only).
factory setting
148
How to Programme
100%
() display text [] value for use in communication via serial communication port
MG.33.B7.02 - VLT is a registered Danfoss trademark
2-17 Over-voltage Control
Value:
Disabled
Enabled (not at stop)
Enabled
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.
Select Disabled [0] if no OVC is required.
Select Enabled [2] to activate OVC.
Select Enabled (not at stop) [1] to activate OVC
except when using a stop signal to stop the fre-
quency converter.
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 (re-
lay 01 or relay 02) or a programmed digital output
(terminal 27 or 29) is required. Normally this out-
put must be closed during periods when the drive
is unable to 'hold' the motor, e.g. due to an ex-
cessive 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 im-
mediately cuts in. This is also the case during safe
stop.
[0]
[1]
[2]