Toshiba VF-FS1 - Manual (Page 91)

E6581381
E-25
5
[Parameter setting]
Title Function Adjustment range Default setting
VJT
Motor electronic thermal
protection level 1
10 – 100 (%) / (A) 100
Setting
value
Overload
protection
Overload
stall
0 { Ч
1 { {
2 Ч Ч
3
Standard
motor
Ч {
4 { Ч
5 { {
6 Ч Ч
QNO
Electronic-thermal protection
characteristic selection
7
VF motor
(special
motor)
× {
{
H
Motor electronic-thermal
protection level 2
10 – 100 (%) / (A) 100
H
Motor 150%-overload time
limit
10 – 2400 (s) 300
H Thermal memory selection
0: Disabled
1: Enabled
0
* { : valid, × : invalid
1) Setting the electronic thermal protection characteristics selection QNO and
motor electronic thermal protection level 1 VJT, 2 H
The electronic thermal protection characteristics selection QNO is used to enable or disable the motor
overload trip function (QN) and the overload stall function.
While the inverter overload trip (QN) will be in constant detect operation, the motor overload trip (QN)
can be selected using the parameter QNO
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 QN is activated. This function operates a
motor at frequencies that allow the load current to keep its balance so that the
inverter can continue operation without being tripped.
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.