4-2 Function Mode „ Thermal Warning •This function outputs an alarm signal before electronic thermal overheat protection is activated. The warning level can be set in C061. •Allocate 13 (THM) to any of multi-function output terminals P1 to P5 (C021 to C025) or the relay output terminal (C026). Overload Limit/Overload Warning This function helps prevent an overcurrent trip due to rapid load fluctuation in acceleration or constant speed operation.
4 Functions „ Overload Limit •The Inverter monitors the motor current during acceleration or constant speed operation in order to lower output frequency automatically according to the overload limit parameter once the motor current reaches the overload limit. •This function prevents an overcurrent trip caused by excessive moment of inertia during acceleration, or caused by rapid load fluctuations during constant speed operation. •You can set two types of overload limit functions in b021/b022/b023 and b024/b025/b026. •To switch between b021/b022/b023 and b024/b025/b026, allocate 39 (OLR) to a multi-function input and then turn it on/off.
•The overload limit level sets a current value for this function to work. •The overload limit parameter sets a time of deceleration from the maximum frequency to 0 Hz. •When this function operates, the acceleration time becomes longer than the set time. •If "sensorless vector control", "0-Hz sensorless vector control", or "sensor vector control" is selected as the control method (V/f characteristics) (refer to "Control Method (V/f Characteristics)" (page 4- 21)), and "03" is selected for b021/b024, the frequency increases when a current exceeding the overload limit level flows during regenerative operation. 4-49 Parameter No.
Function name Data Default setting Unit b021 Overload limit selection 00: Disabled 01: Enabled in acceleration/constant speed operation 02: Enabled in constant speed operation 03: Enabled in acceleration/constant speed operation (accelerates during regeneration) 01 b024 Overload limit selection 2 01 b022 Overload limit level 0.20 × Rated current to 2.00 × Rated current 1.50 × Rated current A b025 Overload limit level 2 1.50 × Rated current A b023 Overload limit parameter 0.1 to 30.00 1.0 s b026 Overload limit parameter 2 1.0 s C040 Overload warning signal output mode 00: Enabled during acceleration/ deceleration/constant speed 01:
Enabled only during constant speed 01 C041 Overload warning level 0.0: Does not operate. 0.1 × Rated current to 2.0 × Rated current (Outputs OL and OL2 signals when reaching the overload warning level.) Rated current A C111 Overload warning level 2 Rated current Related functions C001 to C008, C021 to C025, C026