Since the following two causes are considered, please check the settings.
Maximum output frequency, frequency limiter setting
F03 (Maximum output frequency 1) and F15 (Frequency limiter (upper limit)) may be in operation. The setting range is F03 : 25.0 ~ 500.0 [Hz], F15 : 0.0 ~ 500.00 It becomes [Hz].
Setting the current limit
When the output current of the inverter exceeds the setting current of the operation level, the output frequency is manipulated to limit the output current to prevent stall. F43 (Current limit (operation selection)) and F44 (Current limit (operation level)) to be checked. Set the operation level (20% to 200%) of the current limit function by the rated current ratio of the inverter for the operation level.
Operation selection ( F43 )
Select the operating state in which the current limit function operates.
One point advice
At factory shipping set value, current limit F43 , F44 is "operation". When current exceeding the current limit operation level flows, limit operation is performed and the frequency decreases. H64 (The lowest limiter (minimum frequency at the time of limit operation)) is factory set value is 1.6 [Hz], frequency may be stagnated around 1.6 [Hz] due to limit operation.