Eaton Cutler-Hammer SLX9000 Series, User Manual

Page: 137 / 172

SLX9000 Adjustable Frequency Drives User Manual
MN04003020E For more information visit: www.eaton.com
9-27
January 2009
Figure 9-19: Motor Temperature Calculation
Stall Protection
2.7.10 Motor thermal protection: Motor duty
cycle
ID708
Defines how much of the nominal motor load is applied.
The value can be set to 0% – 100%.
Time Co n sta n t T*
Time
Fault/War n i n g
Par. ID704
* Cha n ges by motor size a n d
adjusted with parameter ID707.
Motor Temperature
= (I/IT)2 x (1-e-t/T)
Motor
Curre n t
I/IT
Trip Area
105 %
Motor
Temperature
The motor stall protection protects the motor from short time overload situations
such as one caused by a stalled shaft. The reaction time of the stall protection can be
set shorter than that of motor thermal protection. The stall state is defined with two
parameters, 2.7.12 (Stall current) and 2.7.13 (Stall frequency). If the current is higher
than the set limit and output frequency is lower than the set limit, the stall state is
true. There is actually no real indication of the shaft rotation. Stall protection is a type
of overcurrent protection.
2.7.11 Stall protection ID709
0 No response
1 Warning
2 Fault, stop mode after fault according to parameter 2.1.12
3 Fault, stop mode after fault always by coasting
Setting the parameter to 0 will deactivate the protection and reset the stall time
counter.