Danfoss VLT AutomationDrive FC 300 Design Manual page 152

FC 300 Design Guide
Function:
This parameter is only active in adjustable frequency
drives with an integral dynamic brake.
The monitoring limit is a product of the maximum
duty cycle (120 sec.) and the maximum
power of the brake resistor at that duty cycle.
See the formula below.
For 200 - 240 V units:
For 380 - 500 V units
For 575 - 600 V units
2-13 Brake Power Monitoring
Option:
*
Off
Warning
Trip
Warning and Trip
Function:
This parameter is only active in adjustable frequency
drives with an integral dynamic brake.
Allows monitoring of the power to the brake
resistor. The power is calculated on the basis of
the resistor ohm value (par. 2-11), the DC link
voltage, and the resistor duty time. If the power
transmitted over 120 s exceeds 100% of the
monitoring limit (par. 2-12) and Warning [1] is
selected, a warning appears on the display.
The warning disappears if the power goes below
80%. If the calculated power exceeds 100% of
the monitoring limit and Trip [2] is selected in par.
2-13 Power Monitoring, the adjustable frequency
drive trips and displays an alarm.
If power monitoring is set to Off [0] or Warning
[1], the brake function remains active, even if the
monitoring limit is exceeded. This may lead to
thermal overload of the resistor. It is also possible
to have a warning via a relay/digital outputs.
The measuring accuracy of the power monitoring
depends on the accuracy of the resistance of
the resistor (better than ± 20%).
2-15 Brake Check
Option:
*
Off
default setting ( ) display text
*
152
How to Program
This parameter is only active in adjustable frequency
drives with an integral dynamic brake.
Enables the integration of a test and monitor
function, which displays a warning or an alarm. On
power-up, the functions is tested for disconnection
of the brake resistor. The test is carried out during
braking. Testing for disconnection of the IGBT,
however, is carried out when there is no braking.
A warning or trip disconnects the brake function.
The testing sequence is as follows:
1.
[0]
2.
[1]
[2]
3.
[3]
4.
Select Off [0]. This function still monitors whether
the brake resistor and the brake IGBT short circuit
during operation. If so, a warning appears. Select
Warning [1] to monitor the brake resistor and brake
IGBT for to short circuiting. During power-up,
disconnection of the brake resistor is checked.
corrected first. With Off [0] or Warning [1], the
adjustable frequency drive keeps running even
if a fault is located. In the case of Trip [2], the
adjustable frequency drive cuts out while displaying
an alarm (trip locked). This happens if the brake
resistor is short circuited, is disconnected, or if
the brake IGBT is short circuited.
[0]
*
[ ] value for use in communication via serial communication port
MG.33.B3.22 - VLT is a registered Danfoss trademark
Warning
Trip
Trip and Stop
Function:
The DC link ripple amplitude is measured
for 300 ms without braking.
The DC link ripple amplitude is measured for
300 ms with the brake turned on.
If the DC link ripple amplitude while braking
is lower than the DC link ripple amplitude
before braking + 1 %. Brake check failed,
return a warning or alarm.
If the DC link ripple amplitude while braking
is higher than the DC link ripple amplitude
before braking + 1 %. Brake check OK
NOTE
Remove a warning arisen in connection
with Off [0] or Warning [1] by cycling
the mains supply. The fault must be
2-17 Over-voltage Control
Option:
Disabled
[1]
[2]
[3]
[0]