4-2 Function Mode •You can select as the Inverter output mode for restart a 0-Hz start, frequency matching start or frequency pull-in restart at free-run stop selection b088. (Examples 1, 2, 3) •If you set frequency matching lower limit frequency setting b007, the Inverter restarts at 0 Hz, when the Inverter detects a frequency equal to or lower than this setting during frequency matching start. •The setting of this function is applied to the FRS terminal, and also to the status when the Inverter is reset from free running. (Example 1) 0-Hz start (Example 2):
Frequency matching start FW FW 4 FRS FRS Free running 0-Hz start Functions Motor rpm 0 Motor rpm 0 matching start • The Inverter starts running at 0 Hz regardless of the motor rpm. The retry wait time is ignored at 0-Hz start. • If the Inverter starts running at 0 Hz with the motor rpm high, an overcurrent trip may occur. • When the FRS terminal is turned off and the retry wait time elapses, the motor frequency is matched and a frequency pull-in starts without stopping the motor. If an overcurrent trip occurs at frequency matching start, extend the retry wait time. • Even if "frequency matching start" is selected, the Inverter may start at 0 Hz when:
• The output frequency is equal to or lower than 1/2 of the base frequency • The motor induction voltage quickly attenuates • The Inverter detects a frequency equal to or lower than the frequency matching lower limit frequency setting (b007) (Example 3) Frequency pull-in restart • After the retry wait time (b003) elapses, the Inverter starts output from the b030 set value. The Inverter then decelerates according to b029, while keeping the output current at the b028 set value. • When the frequency matches the voltage, the Inverter accelerates again, and then output frequency is restored to the original level. • If an overcurrent trip occurs under this method, reduce the b028 set value.
FW FRS b028 Output current Decelerates according to b029. Motor rpm Frequency selected in b030 4-69 Free running b003 b003