• Speed search for general acceleration: If bit 1 is set to 1 and the
inverter operation command runs, acceleration starts with speed
search operation. When the motor is rotating under load, a fault trip
may occur if the operation command is run for the inverter to provide
output voltage. The speed search function prevents such fault trip
from occurring.
• Initialization after a fault trip: If Bit 2 is set to 1 and Pr.08 (RST
Restart) is set to 1 (Yes), the speed search operation automatically
accelerates the motor to the operation frequency used before the
fault trip, when the [Reset] key is pressed (or the terminal block is
initialized) after a fault trip.
• Automatic restart after reset of a fault trip: If bit 3 is set to 1, and
if a low voltage trip occurs due to a power interruption but the power
is restored before the internal power shuts down, the speed search
operation accelerates the motor back to its frequency reference
before the low voltage trip.
If an instantaneous power interruption occurs and the input power is
disconnected, the inverter generates a low voltage trip and blocks the
output. When the input power returns, the operation frequency before
the low voltage trip and the voltage is increased by the inverter’s inner
PI control.
If the current increases above the value set at Cn.72, the voltage
stops increasing and the frequency decreases (t1 zone). If the current
decreases below the value set at Cn.27, the voltage increases again
and the frequency stops decelerating (t2 zone). When the normal
frequency and voltage are resumed, the speed search operation
accelerates the motor back to its frequency reference before the fault
trip.