YASKAWA F7 Programming Manual page 23

AC power supply
Output frequency
Output current
Minimum baseblock time (L2-03) x 0.75 *1
Minimum baseblock time (L2-03) x 0.75*1
Fig. 10 Speed Search (Estimated Speed Method) after momentary power loss where the power loss
AC power supply
Output frequency
Output current
Note: If the frequency immediately before the baseblock is low or the power supply off time is long,
Note: If the frequency immediately before the baseblock is low or the power supply break time is long,
operation may be the same as the search in case 1.
operation may be the same as the search in case 1.
Fig. 11 Speed Search (Estimated Speed Method) after momentary power loss where the power loss
Current Detection Method (b3-01=2 or 3): The current detection method starts searching from a predetermined frequency
while monitoring the Drive output current to determine when the rotor speed and the Drive output speed (frequency) match.
The current detection version is not bi-directional. To enable current detection Speed Search at start set b3-01= "3: SpdscrhI
enable" and program any digital input equal to Speed Search 1 (H1-0x= 61) or Speed Search 2 (H1-0x= 62). Speed Search 1
will start searching from the max. frequency (E1-04) and ramp down to meet the rotor speed. Speed Search 2 will start
searching from the set frequency and ramp down to meet the rotor speed.
IMPORTANT
IMPORTANT
ON
time is less than the minimum baseblock time
ON
Minimum baseblock time
(L2-03)
time exceeds the minimum baseblock time
If a UV1 fault occurs when current detection Speed Search is attempted, increase the setting of L2-04
If an OC fault occurs when Speed Search is attempted after power loss recovery, increase the setting of L2-03.
OFF
Start using
speed detected
10 ms
*1 Baseblock time may be reduced by the output frequency
*2 immediately before the baseblock.
*2 After AC power supply recovery, motor waits for the
minimum Speed Search Wait Time (b3-05).
OFF
Speed Search Wait Time
(b3-05)
Programming 15
Set frequency
reference
the motor waits for the
Start using speed detected
Set frequency
reference
10 ms