2-13 Brake Power Monitoring
Option:
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 on
the basis of the resistance (par.2-11
, the DC-link voltage, and the resistor
duty time.
[0] *
Off
No braking energy monitoring is required.
[1]
Warning
Activates a warning on the display when the power transmitted over 120 s exceeds 100% of the
monitoring limit (par.2-12
The warning disappears when the transmitted power falls below 80% of the monitoring limit.
[2]
Trip
Trips the adjustable frequency drive and displays an alarm when the calculated power exceeds
100% of the monitoring limit.
[3]
Warning and trip
Activates both of the above, including warning, trip and 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 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%).
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 per-
formed 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 adjustable frequency drive 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 adjustable frequency drive ramps down to coast and then trips. A trip
lock alarm is displayed.
[4]
AC brake
NOTE!
NB!: Remove a warning arising in connection with
Off
[0] or
Warning
[1] by cycling the line power supply. The fault must be corrected
first. For
Off
[0] or
Warning
[1], the adjustable frequency drive keeps running even if a fault is located.
3 Parameter Description
VLT
®
HVAC Drive Programming Guide
3-32
MG.11.C6.22 - VLT
®
is a registered Danfoss trademark
3