8.7.1 Motor overload monitoring (i²*t)
This funcon monitors the thermal ulisaon of the motor, taking the motor currents recor-
ded and a mathemacal model as a basis.
DANGER!
Fire hazard by overheang of the motor.
Possible consequences: Death or severe injuries
▶
To achieve full motor protecon, an addional temperature monitoring funcon with a sep-
arate evaluaon must be installed.
▶
When actuang motors that are equipped with PTC thermistors or thermal contacts, always
acvate the PTC input.
Details
This funcon only serves to funconally protect the motor. It is not suitable for the safety-rele-
vant protecon against energy-induced hazards, since the implementaon is not fail-safe.
•
When the thermal motor ulisaon calculated reaches the threshold set in 0x2D4B:001
(P308.01), the response set in 0x2D4B:003 (P308.03) is triggered.
•
With the seng 0x2D4B:003 (P308.03) = "No response [0]", the monitoring funcon is
deacvated.
For a UL-compliant operaon with motor overload protecon, 0x2D4B:002
(P308.02) and 0x2D4B:003 (P308.03) must be le on the default seng! This
seng serves to save the calculated thermal motor ulisaon internally when
the inverter is switched o and reloaded when it is switched on.
If monitoring is deacvated by the seng 0x2D4B:003 (P308.03) = "No response
[0]", no motor overload protecon is acve. In this case, an external motor
overload protecon can be provided by the user for a UL-compliant operaon.
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) is set to "Fault [3]", the response of the motor
overload monitoring may be set other than "Fault [3]" " in 0x2D4B:003
(P308.03).
4Motor temperature monitoring ^ 219
Motor control
Motor protecon
Motor overload monitoring (i²*t)
215