Setting The Electronic Thermal - Toshiba TOSVERT VF-AS1 Instruction Manual

5.14

Setting the electronic thermal

 : Motor electronic thermal protection level 1
: Electronic thermal protection characteristic selection

 : Overload reduction starting frequency
 : Motor 150%-overload time limit
 : Inverter overload selection
• Function
This parameter allows selection of the appropriate electronic thermal protection characteristics according to the
particular rating and characteristics of the motor.
[Parameter setting]
Title
Motor electronic
thermal

protection level 1
Motor overload
protection

characteristic
selection
1) Setting the motor overload protection level 1
selection

The electronic thermal protection characteristics selection  is used to enable or disable the motor overload trip
function () and the overload stall function.
The motor overload trip function () needs to be selected with the parameter , while the inverter overload
trip function () is always activated.
Explanation of terms:
Overload stall (Soft stall)
The function of automatically lowering the output frequency before the motor overload trip function
 is activated when the inverter detects that an excessive load is applied to the motor. (Lowers
maximum about 48Hz when basic frequency is 60Hz.) This function enables the inverter to output a
frequency commensurate with the load current so that the motor can keep running without tripping.
This function is useful for such loads as fans, pump, and blowers, which have the square reduction
torque characteristic that the current passed decreases as the rotating speed falls.
Note: Do not use this overload stall function for loads with a constant torque characteristic (e.g., a belt
conveyer to which a constant load current is always passed regardless of their speed).
[Using general-purpose 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 general-purpose motor is used in
order to prevent overheating.
Setting of electronic thermal protection characteristics selection 
Default setting




Function
~ [%]
Default
Motor type
setting

 Default
Motor



 Motor
(special

motor)

Overload protection
(protect)
(protect)
× (not protect)
× (not protect)
E-21
Adjustment range
Overload
protection
(protect)
(protect)
× (not protect)
× (not protect)
(protect)
VF
(protect)
× (not protect)
× (not protect)
and electronic thermal protection characteristics

Overload stall
× (not stall)
(stall)
× (not stall)
(stall)
E6581301
Default setting

Overload stall
× (not stall)
(stall)
× (not stall)

(stall)
× (not stall)
(stall)
× (not stall)
(stall)
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