2-10 Brake Function
Option:
Function:
Available selections depend on
1-10 Motor
Construction
:
[0] Asynchron:
•
[0] Off
•
[1] Resistor brake
•
[2] AC brake
[1] PM non-salient:
•
[0] Off
•
[1] Resistor brake
[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 only works in Compressor Torque mode
in
1-03 Torque Characteristics
.
2-11 Brake Resistor (ohm)
Range:
Function:
Size
related
*
[ 5.00 -
65535.00
Ohm]
Set the brake resistor value in
Ω
. This
value is used for monitoring the power
to the brake resistor in
2-13 Brake Power
Monitoring
. This parameter is only active
in frequency converters with an integral
dynamic brake.
Use this parameter for values without
decimals. For a selection with 2 decimals,
use
parameter 30-81 Brake Resistor (ohm)
2-12 Brake Power Limit (kW)
Range:
Function:
Size
related
*
[ 0.001 -
2000.000
kW]
Parameter 2-12 Brake Power Limit (kW)
is
the expected average power dissipated in
the brake resistor over the time period
selected within
2-13 Brake Power
Monitoring
. It is used as the monitoring
limit for
16-33 Brake Energy /2 min
and
thereby specifies when a warning/alarm is
to be given.
To calculate
, the following formula can be
used.
Pbr,avg W =
Ubr
2 V ×tbr s
Rbr Ω ×Tbr s
P
br,avg
is the average power dissipated in
the brake resistor, R
br
is the resistance of
the brake resistor. t
br
is the active
breaking time within the 120 s period, T
br
.
2-12 Brake Power Limit (kW)
Range:
Function:
U
br
is the DC voltage where the brake
resistor is active.
NOTICE
If values are unknown, or if T
br
is
different from 120 s, the practical
approach is to run the brake
application, readout
16-33 Brake
Energy /2 min
and then enter this
+20% in
2-12 Brake Power Limit
(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
(
parameter 2-11 Brake Resistor (ohm)
), the
DC-link voltage, and the resistor duty time.
The time periode can be selected in this
parameter.
The functions are as follows:
•
Off
:
Brake power monitoring disabled.
Default setting.
•
Warning (time period)
:
Activates a warning on the display
when the power transmitted over
the selected time period exceeds
100% of the monitoring limit
(
parameter 2-12 Brake Power Limit
). The warning disappears
when the transmitted power falls
below 80% of the monitoring limit.
•
Trip (time period)
;
Trips frequency converter and
displays an alarm when the
calculated power exceeds 100% of
the monitoring limit.
•
Warning & trip (time period)
:
Activates both of the above,
including warning, trip and alarm.
[0]
*
Disabled
Brake power monitoring disabled.
[1]
Warning 120s Warning based on 120 s time periode.
[2]
Trip 120s
Trip based on 120 s time periode.
[3]
Warning &
trip 120s
Warning and trip based on 120 s time
periode.
[4]
Warning 30s
Warning based on 30 s time periode.
[5]
Trip 30s
Trip based on 30s time periode
Programming
Design Guide
MG90O202
Danfoss A/S © Rev. 05/2014 All rights reserved.
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Содержание VLT Brake Resistor MCE 101
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