Danfoss VLT AutomationDrive FC 300 Design Manual page 149

FC 300 Design Guide
ETR trip 3
ETR warning 4
ETR trip 4
Function:
The adjustable frequency drive determines
the motor temperature for motor protection
in two different ways:
Via a thermistor sensor connected to one of the
•
analog inputs, terminals 53 or 54 (par. 1-93).
• Via calculation of the thermal load, based on
the actual load and time. The calculation is
compared with the rated motor current I
the rated motor frequency f
estimate the need for a lower load at lower speed
due to less cooling from the incorporated fan.
If the motor is overloaded, select No protection
if no warning or tripping is required. Select
Thermistor warning to receive a warning when the
connected thermistor in the motor switches off.
Select Thermistor trip if you want the adjustable
frequency drive to cut out (trip) when the connected
thermistor in the motor switches off. Select
thermistor (PTC sensor) if you want a thermistor
integrated in the motor (for winding protection) to
stop the adjustable frequency drive in case of motor
overheating. The cut-out value is > 3 k.
Select ETR Warning 1-4 to receive a warning on
the display when the motor is overloaded. Select
ETR Trip 1-4 to have the adjustable frequency
drive trip when the motor is overloaded. It is
possible to program a warning signal via one of
the digital outputs. The signal appears in case of
a warning and if the adjustable frequency drive
* default setting ( ) display text
How to Program
[8]
[9]
[10]
and
M,N
. The calculations
M,N
[ ] value for use in communication via serial communication port
MG.33.B3.22 - VLT is a registered Danfoss trademark
trips (thermal warning). ETR (Electronic Terminal
Relay) functions 1-4 will not calculate the load
until the unit is switched to the set-up where they
were selected. For the North American market:
The ETR functions provide Class 20 motor overload
protection in accordance with NEC.
1-91 Motor External Fan
Option:
*
No
Yes
Function:
Select whether to apply an external motor fan
(external ventilation), indicating unnecessary
derating at low speed.
If Yes [1] is selected, the graph below is followed
if the motor speed is lower. If the motor speed is
higher, the time still derates as if no fan is installed.
You cannot change par. 1-91 while the
motor is running.
[0]
[1]
149