Danfoss VLT Programming Guide

This parameter is only active in frequency converters with an integral dynamic brake.
2-13 Brake Power Monitoring
Option: 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.
[0] * Off No brake power 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
Brake Power Limit (kW) ).
The warning disappears when the transmitted power falls below 80% of the monitoring limit.
[2] Trip Trips the frequency converter 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 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 failed, return 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 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!
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.
VLT
®
HVAC Drive Programming Guide 3 Parameter Description
MG.11.C9.02 - VLT
®
is a registered Danfoss trademark 61
3

Danfoss VLT Specifications

General

Frequency	50/60 Hz
Enclosure	IP20, IP21, IP55, IP66
Series	VLT
Control Technique	Flux Vector Control
Output Voltage	0-Vinput
Control Method	Fieldbus
Communication Interface	PROFIBUS, CANopen
Protection Features	Overload, Overvoltage, Undervoltage, Short Circuit, Ground Fault
Cooling Method	Liquid Cooled
Storage Temperature	-25°C to +70°C
Relative Humidity	5-95% non-condensing
Altitude	Up to 1000m (3280ft) without derating, up to 4000m (13120ft) with derating
Operating Temperature	-10°C to +50°C (14°F to 122°F)