5-31
F10 to F12
Electronic Thermal Overload Protection for Motor
(Select motor characteristics, Overload detection level, and Thermal time constant)
F10 through F12 specify the thermal characteristics of the motor for its electronic thermal
overload protection that is used to detect overload conditions of the motor inside the inverter.
F10 selects the motor cooling mechanism to specify its characteristics, F11 specifies the overload
detection current, and F12 specifies the thermal time constant.
Thermal characteristics of the motor specified by F10 and F12 are also used for the
overload early warning. Even if you need only the overload early warning, set these
characteristics data to these function codes. To disable the electronic thermal moto
overload protection, set function code F11 to "0.00."
Select motor characteristics (F10)
F10 selects the cooling mechanism of the motor--built-in cooling fan or externally powered
forced-ventilation fan.
Data for F10 Function
1 For general-purpose motors with built-in self-cooling fan
(The cooling effect will decrease in low frequency operation.)
2 For inverter-driven motors or high-speed motors with forced-ventilation fan
(The cooling effect will be kept constant regardless of the output frequency.)
The figure below shows operating characteristics of the electronic thermal overload protection
when F10 = 1. The characteristic factors α1 through α3 as well as their corresponding switching
frequencies f
2 and f3 vary with the characteristics of the motor. The tables below lists the factors
of the motor selected by P99 (Motor Selection).
Cooling Characteristics of Motor Equipped with a Self-cooling Fan
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