Yaskawa F7 Drive Programming Manual - Manual (Page 23)

Programming 15
Fig. 10 Speed Search (Estimated Speed Method) after momentary power loss where the power loss
time is less than the minimum baseblock time
Fig. 11 Speed Search (Estimated Speed Method) after momentary power loss where the power loss
time exceeds the minimum baseblock time
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
If a UV1 fault occurs when current detection Speed Search is attempted, increase the setting of L2-04
IMPORTANT
If an OC fault occurs when Speed Search is attempted after power loss recovery, increase the setting of L2-03.
AC power supply
Output frequency
Output current
OFF ON
Start using
speed detected
Set frequency
reference
Minimum baseblock time (L2-03) x 0.75*1
10 ms
*1 Baseblock time may be reduced by the output frequency
immediately before the baseblock.
*2 After AC power supply recovery, motor waits for the
minimum Speed Search Wait Time (b3-05).
*2
Minimum baseblock time (L2-03) x 0.75 *1
the motor waits for the
AC power supply
Output frequency
Output current
OFF ON
Start using speed detected
Set frequency
reference
Minimum baseblock time
(L2-03)
10 ms
Speed Search Wait Time
(b3-05)
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.
Note: If the frequency immediately before the baseblock is low or the power supply off time is long,
operation may be the same as the search in case 1.