YASKAWA GA800

12.3 b: Application
734 YASKAWA SIEPC71061737D GA800 Drive Technical Reference
Figure 12.28 Current Detection 2 after Momentary Power Loss
Note:
After you restore power, the drive will not do Speed Search until the time set in b3-05 [Speed Search Delay Time] expires. This means that
the drive will not always start Speed Search when the time set in L2-03 [Minimum Baseblock Time] expires.
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 expires. When the value set in L2-03 < b3-05, the drive will use the wait time set in b3-05.
Figure 12.29 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 drive detects oL1 [Motor Overload] during Current Detection Speed Search, decrease 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 L2-03.
• If b3-01 = 1 [Speed Search at Start Selection = Enabled], too much current will flow when the motor starts. If there is too much current at
start it will decrease the service life of the drive IGBTs over time.
■ Speed Estimation
Use this Speed Search function with induction motors. Set b3-24 = 1 [Speed Search 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 (200 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.