AC powersupplyOutputfrequencyOutputcurrentOFFONStarts at the speedthat was detectedSelectedfrequencyreferenceMin. Baseblock Time(L2-03)Several millisecondsb3 -05 <1>Figure 5.11 Speed Search after Baseblock<1> After AC power is restored, the drive will wait for at least the time set to b3-05. If the power interruption is longer thanthe minimum baseblock time set to L2-03, the drive will wait until the time set to b3-05 has passed after power is restoredbefore starting Speed Search.Step 2: Current InjectionCurrent Injection is performed when there is insufficient residual voltage in the motor after extended power losses, when SpeedSearch is applied with the Run command (b3-01 = 1), or when an External search command is used.This feature injects the amount of DC current set to b3-06 to the motor and detects the speed by measuring the current feedback.The drive then outputs the detected frequency and increases the voltage using the time constant set to parameter L2-04 whilelooking at the motor current.The output frequency is reduced if the current is higher than the level in b3-02. When the current falls below b3-02, the motorspeed is assumed to be found and the drive starts to accelerate or decelerate to the frequency reference.Run commandOutputfrequencyOutputcurrentOFF ONb3-02 (Speed search operation current)Starts at the speedspeed that was detectedWaits twice as long as L2-04Frequency referenceset to the driveDecelerates at the SpeedSearch decel time set to b3-031.0 sMin. Baseblock Time (L2-03) <1>Figure 5.12 Speed Search at Start<1> The wait time for Speed Search (b3-05) determines the lower limit.Notes on Using Speed Estimation Speed Search• Perform Rotational Auto-Tuning for V/f Control (T1-01 = 3) prior to using Speed Estimation in V/f Control and performStationary Auto-Tuning for Line-to-Line Resistance (T1-01 = 2) again if the there is a change in the cable length betweenthe drive and motor.• Use Current Detection to search for speeds beyond 200 Hz if the application is running multiple motors from the same driveor if the motor is considerably smaller than the capacity of the drive.• Speed Estimation may have trouble finding the actual speed if the motor cable is very long. Use Current Detection in theseinstances.• Use Current Detection instead of Speed Estimation when operating motors smaller than 1.5 kW because Speed Estimationmight not be able to detect the speed or rotation of these smaller motors, in which case Speed Estimation would stop themotor.5.2 b: ApplicationYASKAWA SIEP YAIP1U 01C AC Drive - P1000 Technical Manual 1555 Parameter Details
