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5.3.3 Selection of electronic thermal characteristics
[SEL
l{ ]
The optimum electronic thermal characteristics can be selected by switching either to those for-
standard motors or variable frequency
(VF)
motors, and also by adding the soft stall function.
Setting
of
SEt
l{
0
1
i
2
I
I
3
i
Function
For standard motors, without soft stall function
For standard motors, with soft stall function
For VF motors, without soft stall function
For VF motors, with soft stall function
• For details on the setting procedure, refer to Section 3.1.1 (page
22). This function number
is 4.
Soft stall function:
When an inverter overload is detected, the program will continue to run without an inverter-halt.
This is made possible by having the inverter's output frequency decreased automatically to a
frequency that balances the load current, before the phase-in of an overload trip mode. ' This
process can be applied to a fan, blower, or any load device whose speed exhibits variable
torque characteristics when the load current diminishes against any dropping run speed.
Do not use the inverter's soft stall function for any constant-torque characteristic load (where
the load current remains fixed regardless of motor speed).
SEL4=
Oor 1
:
Standard motor
Electronic thermal activation level
60%
o
45Hz
I
Adjusted on tHr
I
Maximum frequency
output
frequency
Figure 5.4 Electronic thermal activation characteristic for standard motors
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