Motor Overload Monitoring (I²*T) - Lenze i55AE125B Manual

8.7.1 Motor overload monitoring (i²*t)
This function monitors the thermal utilisation of the motor, taking the motor currents recor-
ded and a mathematical model as a basis.
DANGER!
Fire hazard by overheating of the motor.
Possible consequences: Death or severe injuries
▶ To achieve full motor protection, an additional temperature monitoring function with a sep-
arate evaluation must be installed.
▶ When actuating motors that are equipped with PTC thermistors or thermal contacts, always
activate the PTC input.
Details
This function only serves to functionally protect the motor. It is not suitable for the safety-rele-
vant protection against energy-induced hazards, since the implementation is not fail-safe.
When the thermal motor utilisation calculated reaches the threshold set in
•
(P308.01), the response set in
With the setting 0x2D4B:003 (P308.03)
•
deactivated.
For a UL-compliant operation with motor overload protection,
(P308.02) and
setting serves to save the calculated thermal motor utilisation internally when
the inverter is switched off and reloaded when it is switched on.
If monitoring is deactivated by the setting
[0]", no motor overload protection is active. In this case, an external motor
overload protection can be provided by the user for a UL-compliant operation.
If a suitable motor temperature sensor is connected to the terminals X109/T1
and X109/T2 and the response to the triggering of the motor temperature mon-
itoring in 0x2D49:002 (P309.02)
overload monitoring may be set other than "Fault [3]" " in
(P308.03).
4Motor temperature monitoring
0x2D4B:003 (P308.03)
= "No response [0]", the monitoring function is
0x2D4B:003 (P308.03) must be left on the default setting! This
is set to "Fault [3]", the response of the motor
^ 219
0x2D4B:001
is triggered.
0x2D4B:002
0x2D4B:003 (P308.03) = "No response
0x2D4B:003
Motor control
Motor protection
Motor overload monitoring (i²*t)
215