Toshiba Tosvert VF-S15 Instruction Manual page 368

1) Setting the electronic thermal protection characteristics selection olm
and motor electronic thermal protection level 1 thr, 2 f173
The electronic thermal protection characteristics selection (olm) is used to enable or disable the motor overload trip
function (ol2) and the overload stall function.
While the inverter overload trip (ol1) will be in constantly detective operation, the motor overload trip (ol2) can be
selected using the parameter olm
Explanation of terms
Overload stall: This is an optimum function for equipment such as fans, pumps and blowers with variable torque
characteristics that the load current decreases as the operating speed decreases.
When the inverter detects an overload, this function automatically lowers the output frequency before the motor
overload trip (ol2) is activated. With this function, operation can be continued, without tripping, by operating
using a frequency balanced by load current.
Note: Do not use the overload stall function with loads having constant torque characteristics (such as conveyor
belts in which load current is fixed with no relation to speed).
[Using standard motors (other than motors intended for use with inverters)]
When a motor is used in the lower frequency range than the rated frequency, that will decrease the cooling effects for
the motor. This speeds up the start of overload detection operations when a standard motor is used in order to prevent
overheating.
 Setting of electronic thermal protection characteristics selection olm
Setting value
0
1
2
3
 Setting of motor electronic thermal protection level 1 thr (Same as f173)
When the capacity of the motor in use is smaller than the capacity of the inverter, or the rated current of the motor
is smaller than the rated current of the inverter, adjust thermal protection level 1 thr for the motor in
accordance with the motor's rated current.
Output current reduction factor
Overload protection Overload stall
valid invalid
valid valid
invalid invalid
invalid valid
[%]/[A]
×1.0
×0.6
0
30Hz
Note: The motor overload protection start level is fixed at 30Hz.
Q-12
Output frequency (Hz)
E6581926