Omron Q2A Series Technical Manual page 531

Note:
• To use Speed Estimation Speed Search with V/f Control, do Rotational Auto-Tuning before you set the Speed Search function. If the
wire length between the drive and motor changed since the last time you did Auto-Tuning, do Stationary Auto-Tuning for Line-to-Line
Resistance process again.
• If A1-02 = 5, 6 [PM OLVector, PM AOLVector] and the wiring distance between the motor and drive is long or if the motor is coasting
at more than or equal to 200 Hz, do not use Speed Search to restart the motor. Use Short Circuit Braking.
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Current Detection 2
Use this Speed Search function with induction motors. Set b3-24 = 2 [SpSrch Method Selection = Current Det2].
Current Detection Speed Search injects current into the motor to detect the speed of an induction motor. Speed
Search increases the output voltage for the time set in L2-04 [Powloss Ramp Time@recovery], starting from the
maximum output frequency or the frequency reference.
Figure 12.22 Current Detection Speed Search after Momentary Power Loss
Note:
After you return power, the drive will not do Speed Search until the time set in b3-05 [SpSrch Delay Time] is expired. Thus, the drive
will not always start Speed Search although the time set in L2-03 [Min Baseblck Time] is expired.
If you enter the Run command at the same time as Speed Search, the drive will not do Speed Search until the time
set in L2-03 is expired. If the value set in L2-03 < b3-05, the drive will use the wait time set in b3-05.
Figure 12.23 Speed Search Selection at Start (Current Detection Type)
WARNING! Sudden Movement Hazard. If you do Current Detection Speed Search with light loads or a stopped motor, the
motor can suddenly accelerate and cause serious injury or death.
Note:
• You cannot use Current Detection Speed Search with PM motors.
• If the motor is rotating in reverse, you cannot do Speed Search.
• If the drive detects oL1 [Motor Overload] during Current Detection Speed Search, decrease the value set in b3-03.
• If the drive detects oC [Overcurrent] or ov [Overvoltage] during Current Detection Speed Search after the drive recovers from a
momentary power loss, increase the value set in L2-03.
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Speed Estimation
Use this Speed Search function with induction motors. Set b3-24 = 1 [SpSrch Method Selection = Speed
Estimation]. This function uses less current and has a shorter search time than other functions. This function lets
you do Speed Search when the motor is rotating in reverse. When you return power after a power loss, the motor
will not suddenly accelerate.
SIEPYEUOQ2A01A AC Drive Q2A Technical Manual
12.2 b: APPLICATION
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