Toshiba TOSVERT VF-MB1 Instruction Manual page 70

[Using a VF motor (motor for use with inverter)]
 Setting of electronic thermal protection characteristics selection 
Setting value Overload protection




VF motors (motors designed for use with inverters) can be used in frequency ranges lower than those
for standard motors, but their cooling efficiency decreases at frequencies below 6Hz.
 Setting of motor electronic thermal protection level 1  (Same as f173)
If the capacity of the motor 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 the electronic thermal protection level 1  so
that it fits the motor's rated current.
* If the indications are in percentages (%), then 100% equals the inverter's rated output current (A).
Output current reduction factor [%] / [A]
2) Motor 150%-overload detection time f607
Parameter f607 is used to set the time elapsed before the motor trips under a load of 150% (overload trip
2 ) within a range of 10 to 2400 seconds. 
3) Inverter overload characteristics f631
This function is set to protect the inverter unit. This function cannot be turned off by parameter setting.
The inverter has two overload detecting functions, which can be switched from one to another using
parameter  (Inverter overload detection method).
[Parameter setting]
Title
Inverter overload detection method

If the inverter overload trip function (  ) is activated frequently, this can be improved by adjusting the stall
operation level  downward or increasing the acceleration time  or deceleration time  .
Overload stall
valid invalid
valid valid
invalid invalid
invalid valid
 ×1.0
 ×0.6
0
6Hz
Note) The start level for motor overload reduction is fixed at 6 Hz.
Function
0: 150%-60s (120%-60s)
1: Temperature estimation
C-19
Output frequency (Hz)
Adjustment range
E6581697
3
Default setting
0