Danfoss FC 300 Programming Manual page 48

Parameter Descriptions
2-12 Brake Power Limit (kW)
Range:
Application
dependent
*
3 3
For 200 - 240 V
units:
For 380 - 480 V
units
For 380 - 500 V
units
For 575 - 600 V
units
This parameter is only active in frequency converters with an
integral dynamic brake.
2-13 Brake Power Monitoring
Option:
[0] Off
*
[1] Warning
[2] Trip
[3] Warning
and trip
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 generate 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%).
48
Function:
[Application Set the monitoring limit of the brake
dependant] power transmitted to the resistor.
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.
2
dutytime
390 ×
P resistor
=
R
× 120
2
dutytime
778 ×
P resistor
=
R
× 120
810 2 ×
dutytime
P resistor
=
R × 120
943 2 ×
dutytime
P resistor
=
R
× 120
Function:
This parameter is only active in frequency
converters with an integral dynamic brake.
This parameter enables monitoring of the power
to the brake resistor. The power is calculated on
the basis of the resistance (par. 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 (par. 2-12 Brake Power Limit
(kW) ).
The warning disappears when the transmitted
power falls below 80% of the monitoring limit.
Trips frequency converter and displays an alarm
when the calculated power exceeds 100% of the
monitoring limit.
Activates both of the above, including warning,
trip and alarm.
MG.33.M9.02 - VLT
FC 300 Programming Guide
2-15 Brake Check
Option:
[W]
[W]
[W]
[W]
[0] Off
*
[1] Warning
[2] Trip
[3] Stop and
trip
[4] AC brake
[5] Trip Lock
®
is a registered Danfoss trademark
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.
NOTE
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 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.
Monitors brake resistor and brake IGBT for a short-
circuit during operation. If a short-circuit occurs,
warning 25 appears.
Monitors brake resistor and brake IGBT for a short-
circuit, and runs a test for brake resistor disconnec-
tion during power-up.
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).
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 (e.g. warning 25, 27 or 28).
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.