Santerno Sinus M, User Manual, Page: 129 / 219

10-29

EX) Speed search during Instant Power Failure restart

When the input power is cut off due to instant power failure, the inverter trips (LV).

When the power is restored, the inverter supplies the motor with the frequency stored before
the low voltage trip and the voltage is increased due to speed search PI control.

t1: If current is increasing over the preset level in H23, the voltage increasing will stop and the
frequency is decreased.

t2: If the opposite of t1 occurs, the voltage increasing starts again and the output frequency
stops to decrease.

When the frequency and voltage will reach their nominal level, the inverter will follow the
acceleration ramp until the stored frequency before low voltage (LV) trip is reached.

Speed search operation is suitable for loads with high inertia.

Sinus M keeps normal operation when instant power failure occurs and power is restored in 15msec.
Input
voltage
Frequency
Voltage
Current
H23
t1 t2
Multi-function
output or
Relay