Motor Electronic Thermal Time Constant (F12/A08)
• Set the thermal time constant of the motor. Set the electronic thermal operating time for when a cur-
rent of 150% of the operation level set at Motor Electronic Thermal Level (F11/A07) flows continu-
ously. The thermal time constant of a general motor is 5 minutes for 22kW or less (factory default).
(Example) When the data of F12/A08 is set to 5 (5 minutes)
When a current 150% of the overload detection level set as shown in the figure below flows for 5 mi-
nutes, the motor overload (alarms OL1/OL2) protection function operates. Also, for 120%, the motor
overload protection function operates after approx. 12.5 minutes.
The time that an alarm actually is generated is shorter than the set data as the time from when the
continuous allowable current (100%) is exceeded up to when the 150% level is reached also is taken
into consideration.
50
100 150
200
F12 = 0.5
F12 = 5
F12 = 10
(Output current value / Operation level current value) × 100 (%)
0
0
5
10
15
20
Operation time (minutes)
Change with F12
Motor Electronic Thermal Warning
Use this function to output a warning signal before the motor electronic thermal function executes an
overload protection. The electronic thermal warning operates at or above the current value set in the
Overload early warning 2 Level (OL2) (E34). Generally, set to around 80% to 90% of the current value
of the Motor Electronic Thermal Level (F11/A07). The temperature characteristics of the motor are set
in Motor Electronic Thermal Characteristic Selection (F10/A06) or Motor Electronic Thermal Time Con-
stant (F12/A08).
Parameter No. Function name Data
Default
data
Unit
E20, E21, E27
Output Terminal [DO1] Function
Selection, Output Terminal [DO2]
Function Selection, Output Termi-
nal [ROA, ROB] Function Selec-
tion
7: THM (Electronic thermal warn-
ing)
- -
5 Basic Settings
5-23
M1 Series Standard Type User's Manual (I669)
5-3 Motor Parameter Settings
5
5-3-3 Motor Electronic Thermal Function
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