38 
 
 
 
 
  F_18: Motor rated current = 50~100 %(0~200%: CPU version v1.9 and  
           above) 
 
1.  The electronic thermal overload protection for motor: 
(1)  Motor rated current = Inverter rated current x F_18 
F_18 = Motor rated current / inverter rated current 
 
(2)  When the load is within 100% of the motors rated current, the operation continues. When the 
load reaches 150% of the motors rated current the operation is allowed to continue for 1 
minute. (Refer to curve (1) in Figure 3) 
 
(3) After protecting the motor with the electronic thermal switch activated, the inverter is cut off 
immediately. The OLI light will flash. To resume operation, push the RESET button or activate 
an external reset connection wired to terminal 2. 
 
(4) When the motor is operating at low speeds, the heat dissipation efficiency is lower. The 
electronic thermal activation level is also reduced. (to change from curve (1) to curve (2) in 
Figure 3. Choose the appropriate F_05 setting according to the applied motor to reach the 
desired performance. 
 
2.  The electronic thermal protecting for inverter: 
 
(1)  When the load is within 103% of the inverters rated current, the operation continues. 
When the load reaches 150% of rated current of the inverter, the operation will 
continue for 1 minute. (Refer to curve (1) of figure 3) 
 
(2)     After the activation of the electronic thermal switch,  the inverter is shut off immediately. The 
OL2 light will flash. To resume the operation, push RESET button or activate an external reset 
contact on terminal 2. 
 
 
 
 
 
 
 
 
 
 
 
F_05 = 1,2,3 
50 Hz standard motors 
% 
F_05 = 4,5,6 
60 Hz standard motors
100
90 
60
 
100
90 
60
 
Deca
 
Minute 
20 50  
  (Figure 1) 
20        60   
          100       150 
     (Figure 3) 
In Percentage of Current 
      (Figure 2) 
1.0
Decay
 
% 
% of 
current