Danfoss VLT FC 302 Operating Instructions Manual page 57

Programming
12 13 18 19 27 29 32 33 20 37
PTC / Thermistor
Illustration 6.6 Klixon Example
1-93 Thermistor Source
Option: Function:
NOTICE
This parameter cannot be adjusted
while the motor is running.
NOTICE
Set digital input to [0] PNP - Active at
24 V in 5-00 Digital I/O Mode.
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, option [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
2-10 Brake Function
Option: Function:
[0] Off No brake resistor is installed.
*
[1] Resistor A brake resistor is incorporated in the system, for
brake 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
overmagnetisation of the motor when running
MG37A202
Operating Instructions
OFF
ON
<6.6 k Ω >10.8 k Ω R
Danfoss A/S © Rev. 2014-07-29 All rights reserved.
2-10 Brake Function
Option: Function:
with a generatoric load. This function can
improve the OVC-function. Increasing the
electrical losses in the motor allows the OVC
function to increase the braking torque without
exceeding the overvoltage limit. Note that AC
brake is not as effective as dynamic braking with
a resistor.
AC brake is for VVC
open and closed loop.
2-11 Brake Resistor (ohm)
Range: Function:
Set the brake resistor value in Ω. This
Size [ 5.00 -
related 65535.00
value is used for monitoring the power
*
Ohm]
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 30-81 Brake Resistor
(ohm).
2-12 Brake Power Limit (kW)
Range: Function:
Size [ 0.001 - Parameter 2-12 Brake Power Limit (kW) The
related 2000.000 expected average power dissipated in the
*
kW] brake resistor over a period of 120 s. It is
used as the monitoring limit for
16-33 Brake Energy /2 min and specifies
when a warning/alarm is issued.
To calculate 2–12 Brake Power Limit (kW),
use the following formula:
P br,avg W =
P is the average power dissipated in
br,avg
the brake resistor
R is the resistance of the brake resistor.
br
t is the active breaking time within the
br
120 s period, T
U is the DC voltage where the brake
br
resistor is active, depending 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: 1,099 V
plus
and flux mode in both
U br 2 V × t br s
R br Ω × T br s
.
br
55
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