Danfoss VLT, Programming Manual

Page: 47 / 231

3.4 Main Menu - Brakes - Group 2
3.4.1 2-0* DC-Brakes
Parameter group for configuring the DC brake and DC hold
functions.
2-00 DC Hold/Preheat Current
Range: Function:
50 %
*
[0 - 160.
%] Enter a value for holding current as a
percentage of the rated motor current I
M,N
set in
1-24 Motor Current . 100% DC holding current
corresponds to I
M,N
.
This parameter holds the motor (holding
torque) or pre-heats the motor.
This parameter is active if [1] DC hold/Preheat is
selected in
1-80 Function at Stop .
NOTE
The maximum value depends on the rated motor current.
Avoid 100 % current for too long. It may damage the motor.
2-01 DC Brake Current
Range: Function:
50
%
*
[0 -
1000. %] Enter a value for current as a percentage of the
rated motor current I
M,N
, see 1-24 Motor Current .
100% DC braking current corresponds to I
M,N
.
DC brake current is applied on a stop command,
when the speed is lower than the limit set in
2-03 DC Brake Cut In Speed [RPM] ; when the DC
Brake Inverse function is active; or via the serial
communication port. The braking current is
active during the time period set in
2-02 DC
Braking Time .
NOTE
The maximum value depends on the rated motor current.
Avoid 100 % current for too long. It may damage the motor.
2-02 DC Braking Time
Range: Function:
10.0 s
*
[0.0 - 60.0 s] Set the duration of the DC braking current
set in 2-01 DC Brake Current , once activated.
2-03 DC Brake Cut In Speed [RPM]
Range: Function:
Size related
*
[0 - par. 4-13 RPM]
2-04 DC Brake Cut In Speed [Hz]
Range: Function:
Size related
*
[0.0 - par. 4-14 Hz]
3.4.2 2-1* Brake Energy Funct.
Par. group for selecting dynamic braking parameters. Only
valid for drives with brake chopper.
2-10 Brake Function
Option: Function:
[0]
*
Off No brake resistor installed.
[1] Resistor
brake Brake resistor incorporated in the system, for
dissipation of surplus brake energy as heat.
Connecting a brake resistor allows a higher DC
link voltage during braking (generating
operation). The Resistor brake function is only
active in frequency converters with an integral
dynamic brake.
[2] AC brake AC Brake will only work in Compressor Torque
mode in
1-03 Torque Characteristics .
2-11 Brake Resistor (ohm)
Range: Function:
Size related
*
[5.00 - 65535.00 Ohm]
2-12 Brake Power Limit (kW)
Range: Function:
Size related
*
[0.001 - 2000.000 kW]
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 (
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 (
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%).
Parameter Description
VLT
®
HVAC Drive Programming Guide
46 MG.11.CB.02 - VLT
®
is a registered Danfoss trademark
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