Ul 508-Compliant Motor Overload Monitoring - Lenze i950 Commissioning Manual

13.9.1.3

UL 508-compliant motor overload monitoring

If the operation of the motor requires the compliance with the UL Standard 508, and the UL
508-compliant motor overload monitoring is realised by the mathematical model of the I²xt
monitoring, the following conditions must be observed.
UL 508 condition 3:
After mains switching and a motor load > 100 %, the I²xt warning must be output faster than
in the same overload case before mains switching.
A motor load > 100 % exists if the r.m.s. value of the total motor current displayed in
•
parameter 0x2DD1:005 is higher than the rated motor current 0x6075.
This condition can be fulfilled by setting the following parameters:
• Motor utilisation (I²xt): starting value
UL 508 condition 2:
In case of a motor load of 110 %, the I²xt warning at a motor rotating field frequency of 10 Hz
must be output faster than at a motor rotating field frequency of 20 Hz.
The current motor rotating field frequency is displayed in parameter 0x2DDD.
•
A motor load of 110 % exists if the r.m.s. value of the total motor current displayed in
•
parameter 0x2DD1:005 corresponds to 110 % of the rated motor current 0x6075.
This condition can be fulfilled by setting the following parameters:
• I²xt: x1 = n01/nN (n01 ~ 0)
I²xt: y1 = i01/iN (x = n01 ~ 0)
•
• I²xt: x2 = n02/nN (n02 = reduced cooling limit)
• I²xt: y2 = i02/iN (x = n02 = reduced cooling limit
UL 508 condition 1:
In case of a motor load of 600 %, the I²xt warning must be output within 20 seconds.
A motor load of 600 % exists if the r.m.s. value of the total motor current displayed in
•
parameter 0x2DD1:005 corresponds to 600% of the rated motor current 0x6075.
This condition can be fulfilled by setting the following parameters:
Motor utilisation (I²xt): thermal time constant - laminated core
•
Motor utilisation (I²xt): influence winding
•
• Motor utilisation (I²xt): motor overload warning threshold
Motor utilisation (I²xt): response
•
Motor utilisation (I²xt): error threshold
•
40x2D4C:004
40x2D4D:001
40x2D4D:002
40x2D4D:003
40x2D4D:004
40x2D4C:003
40x2D50:001
40x2D50:002
Configuring the motor control
Motor overload monitoring (i²*t)
40x2D4C:002
40x2D4E
Motor protection
271