Danfoss VLT AutomationDrive FC 302 Instruction Manual page 62

Programming
2-12 Brake Power Limit (kW)
Range:
6 6
2-13 Brake Power Monitoring
Option:
[0] Off
[1] Warning
[2] Trip
[3] Warning
and trip
If power monitoring is set to [0] Off or [1] Warning, the
brake function remains active, even if the monitoring limit
is exceeded, possibly leading to thermal overload of the
resistor. It is also possible to generate a warning via a
relay/digital output. The measuring accuracy of the power
monitoring depends on the accuracy of the resistance of
the resistor (better than ± 20%).
60
Instruction Manual
Function:
U is the DC voltage where the brake
br
resistor is active, depending on the unit
as follows:
T2 units: 390 V
T4 units: 778 V
T5 units: 810 V
T6 units: 943 V/1099 V for D – F frames
T7 units: 1,099 V
NOTICE!
If R is not known or if T
br
different from 120 s, the practical
approach is to run the brake
application, readout 16-33 Brake
Energy /2 min and then enter + 20%
in 2-12 Brake Power Limit (kW).
Function:
This parameter is only active in adjustable
frequency drives with an integral dynamic brake.
This parameter enables monitoring of the power
to the brake resistor. The power is calculated
based on the resistance (parameter 2-11 Brake
Resistor (ohm)), the DC link voltage, and the
resistor duty time.
No brake power monitoring required.
Activates a warning on the display when the
power transmitted over 120 s exceeds 100% of
the monitoring limit (parameter 2-12 Brake Power
Limit (kW)).
The warning disappears when the transmitted
power falls below 80% of the monitoring limit.
Trips adjustable frequency drive and displays an
alarm when the calculated power exceeds 100%
of the monitoring limit.
Activates both of the above, including warning,
trip and alarm.
Danfoss A/S © Rev. 2014-02-07 All rights reserved.
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
alarm in the event of a fault.
NOTICE!
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
is brake function.
br
The testing sequence is as follows:
[0] Off Monitors brake resistor and brake IGBT for a short-
circuit during operation. If a short-circuit occurs,
Warning 25 appears.
NOTICE!
Remove a warning arising with [0] Off or [1] Warning by
cycling the line power supply. The fault must be
corrected first. For [0] Off or [1] Warning, 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.
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 braking + 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 braking + 1%: Brake check is OK.
MG37A222