Omron Q2V Series Technical Manual page 458

12.2 b: APPLICATION
Note:
Once power is restored, the drive will not execute Speed Search until the time set in b3-05 [SpSrch Delay Time] has passed. 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. When 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. Do not do Current Detection Speed Search with light loads or a stopped motor. If you
do Auto-Tuning in these conditions, 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.
Note:
You cannot do Speed Estimation Speed Search in these conditions:
• When You Operate More than One Motor with One Drive
• When you use a high-speed motor (120 Hz or higher)
• When you use a 1.5 kW or smaller motor.
• When the motor output is more than 1 frame size smaller than the drive capacity
• When there is a long wiring distance between the drive and motor
For these conditions, use Current Detection Speed Search.
Speed Estimation Speed Search uses these two steps to estimate the motor speed:
1. Residual Voltage Search
When there is a short baseblock time, the drive searches for residual voltage. The drive uses the residual
voltage in the motor to estimate the motor speed and direction of rotation. The drive outputs the estimated
motor speed as frequency, then uses the deceleration rate set in L2-04 to increase the voltage. When the output
voltage aligns with the V/f pattern, the drive accelerates or decelerates the motor to the frequency reference. If
the drive cannot estimate the motor speed because of low residual voltage, it will automatically do Current
Injection.
458 SIEPCYEUOQ2V01A Q2V Technical Manual