2-15 Brake Check
Option:
Function:
Select type of test and monitoring function to check the connection to the brake resistor, or whether
a brake resistor is present, and then display a warning or an alarm in the event of a fault. The brake
resistor disconnection function is tested during power-up. However the brake IGBT test is performed
when there is no braking. A warning or trip disconnects the brake function.
The testing sequence is as follows:
1.
The DC link ripple amplitude is measured for 300 ms without braking.
2.
The DC link ripple amplitude is measured for 300 ms with the brake turned on.
3.
If the DC link ripple amplitude while braking is lower than the DC link ripple amplitude
before b 1 %. Brake check failed, return 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 OK.
[0] *
Off
Monitors brake resistor and brake IGBT for a short-circuit during operation. If a short-circuit occurs,
a warning appears.
[1]
Warning
Monitors brake resistor and brake IGBT for a short-circuit, and to run a test for brake resistor dis-
connection 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 frequency converter 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 frequency converter ramps down to coast and then trips. A trip lock alarm
is displayed.
[4]
AC brake
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.
2-16 AC brake Max. Current
Range:
Function:
100.0 %*
[Application dependant]
Enter the maximum permissible current when using AC brake to avoid overheating of motor wind-
ings. 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.
[2] *
Enabled
Activates OVC.
NB!
The ramp time is automatically adjusted to avoid tripping of the frequency converter.
2 Parameter Description
VLT
p
Automation VT Drive FC322
Programming Guide
54
MG.20.W1.22 - VLT
p
is a registered Danfoss trademark
2
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