Danfoss VLT AutomationDrive FC 300 Operating Instructions Manual page 74

How to Programme the Low Ha...
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PTC / Thermistor
Illustration 6.7
1-93 Thermistor Source
Option: Function:
Select the input to which the thermistor
(PTC sensor) should be connected. An
analog input option [1] or [2] cannot be
selected if the analog input is already in
use as a reference source (selected in
3-15 Reference 1 Source, 3-16 Reference 2
Source or 3-17 Reference 3 Source).
When using MCB 112, choice [0] None
must always be selected.
[0] None
*
[1] Analog input 53
[2] Analog input 54
[3] Digital input 18
[4] Digital input 19
[5] Digital input 32
[6] Digital input 33
NOTE
This parameter cannot be adjusted while the motor is
running.
NOTE
Digital input should be set to [0] PNP - Active at 24V in
5-00 Digital I/O Mode.
2-10 Brake Function
Option: Function:
[0] Off No brake resistor is installed.
*
[1] Resistor A brake resistor is incorporated in the system,
brake 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 Is selected to improve braking without using a
brake resistor. This parameter controls an
overmagnetization of the motor when running
with a generatoric load. This function can
improve the OVC-function. Increasing the
electrical losses in the motor allows the OVC
VLT Automation Low Harmonic Drive Operating Instructions
OFF
ON
<6.6 k Ω >10.8 k Ω R
®
MG34O202 - VLT is a registered Danfoss trademark
2-10 Brake Function
Option: Function:
function to increase the braking torque without
exceeding the over voltage limit. Please note
that AC brake is not as effective as dynamic
breaking with resistor.
AC brake is for VVC
open and closed loop.
2-11 Brake Resistor (ohm)
Range: Function:
Size [ 5.00 - Set the brake resistor value in Ohms.
related 65535.00 This value is used for monitoring the
*
Ohm] 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 two
decimals, use 30-81 Brake Resistor
(ohm).
2-12 Brake Power Limit (kW)
Range: Function:
Size [ 0.001 - 2-12 Brake Power Limit (kW) is the expected
related 2000.000 average power dissipated in the brake
*
kW] resistor over a period of 120 sec. 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 2-12 Brake Power Limit (kW),
the following formula can be used.
P br,avg W =
P is the average power dissipated in
br,avg
the brake resistor, R
the brake resistor. t
time within the 120 s period, T
U is the DC voltage where the brake
br
resistor is active. This depends on the unit
as follows:
T2 units: 390 V
T4 units: 778 V
T5 units: 810 V
T6 units: 943V/1099V for D – F frames
T7 units: 1099 V
NOTE
If R is not known or if T
br
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).
plus and flux mode in both
U br 2 V × t br s
R br Ω × T br s
is the resistance of
br
is the active breaking
br
.
br
is different
br
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