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Thermal time constant (F12)㩷
F12 specifies the thermal time constant of the motor. If the current of 150% of the overload
detection level specified by F11 flows for the time specified by F12, the electronic thermal
overload protection becomes activated to detect the motor overload. The thermal time
constant for general-purpose motors including Fuji motors is approx. 5 minutes by factory
default.
- Data setting range: 0.5 to 75.0 (minutes) in increments of 0.1 (minute)
(Example) When the F12 data is set at "5.0" (5 minutes)
As shown below, the electronic thermal overload protection is activated to detect an alarm
condition (alarm code
N
) when the output current of 150% of the overload detection level
(specified by F11) flows for 5 minutes, and 120% for approx. 12.5 minutes.
The actual driving time required for issuing a motor overload alarm tends to be shorter than
the value specified as the time period from when the output current exceeds the rated current
(100%) until it reaches 150% of the overload detection level.
Example of Operating Characteristics
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