5.5.3 CON-70 Speed Search Operation
Speed Search is used to start the inverter while the motor/load are already spinning (idling).
Speed Search synchronizes the inverter output (voltage and frequency) to that of the spinning
motor. This is accomplished by ramping up the output voltage then ramping down the output
frequency. Speed Search estimates the motor rotation speed based on the inverter output current;
therefore, it may not match the exact speed. Speed Search can prevent faults that occur when
starting the inverter while the motor/load are spinning.
There are three modes of Speed Search (Flying Start-1, Flying Start-2 and Flying Start-3 (PM)).
The main difference between -1 and -2 is that Flying Start-2 can detect direction of motor rotation.
Flying Start-3 is for PM Motors. Refer to 7.2 PM (Permanent-Magnet) Motors on pg. 246). There
are also four conditional settings of Speed Search. These include during accelerating (normal)
starting, starting after a fault reset, starting after a power interruption, and auto starting with the
initial application of power to the inverter.
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