YASKAWA U1000 iQpump Drive, Technical Manual, Page: 199 / 706

n Speed Estimation Speed Search 2 (b3-24 = 3)
Speed Estimation Speed Search is used in V/f w/PG control mode.
Speed Estimation Speed Search 2 estimates the motor rotation direction while the motor is coasting and then restarts operation.
The drive uses PG feedback to control motor speed. The speed then accelerates or decelerates to the frequency reference after
completing Speed Search.
b3-14 sets how the drive determines the motor rotation direction when performing Speed Estimation Speed Search 2:
• The drive uses the frequency reference to determine the direction of motor rotation in order to restart the motor.
• The drive detects the motor rotation direction in order to restart the motor.
Notes on Using Speed Estimation Speed Search
• Perform Rotational Auto-Tuning for V/f Control (T1-01 = 3) prior to using Speed Estimation in V/f Control and perform
Stationary Auto-Tuning for Line-to-Line Resistance (T1-01 = 2) again if the there is a change in the cable length between
the drive and motor.
• Use Current Detection Speed Search 2 to search for speeds beyond 200 Hz if the application is running multiple motors
from the same drive or if the motor is considerably smaller than the capacity of the drive.
• Speed Estimation may have trouble finding the actual speed if the motor cable is very long. Use Current Detection Speed
Search 2 in these instances.
• Use Current Detection Speed Search 2 instead of Speed Estimation when operating motors smaller than 1.5 kW because
Speed Estimation might not be able to detect the speed or rotation of these smaller motors, in which case Speed Estimation
would stop the motor.
n Speed Search Activation
Speed Search can be activated using any of the methods 1 through 5 described below. Select the Speed Search type in parameter
b3-24 independent of the activation method.
Method 1. Automatically activate Speed Search with every Run command. Set b3-01, Speed Search Selection at Start, to 1
(Enabled). External Speed Search commands are ignored.
Method 2. Activate Speed Search using the digital input terminals.
Use the input functions for H1-
oo
in Table 5.7 .
Table 5.7 Speed Search Activation by Digital Inputs
Setting Description b3-24 = 1, 3 b3-24 = 2, 4
61
External Search
Command 1
Activate Speed Estimation
Speed Search
Closed: Activate Current Detection Speed Search from the
maximum output frequency (E1-04).
62
External Search
Command 2
Closed: Activate Current Detection Speed Search from the
frequency reference.
To activate Speed Search by a digital input, the input must be set together with the Run command or the Run command must
be entered after giving the Speed Search command.
Method 3. After automatic fault restart.
When the number of maximum fault restarts in parameter L5-01 is set higher than 0, the drive will automatically perform
Speed Search as specified by b3-24 following a fault.
Method 4. After momentary power loss.
This mode requires that the Power Loss Ride-Thru function is enabled during CPU operation (L2-01 = 1 or 2). Refer to L2-01:
Momentary Power Loss Operation Selection on page 314 .
Method 5. After external baseblock is released.
The drive will resume the operation starting with Speed Search if the Run command is present and the output frequency is
above the minimum frequency when the Baseblock command (H1- oo = 8 or 9) is released.
n Rotation Direction Detection Conditions for Backspin
Backspin occurs when the motor rotates in the opposite direction from the rotation direction command. Specify the speed
search direction when power is recovered after a momentary power loss in applications in which backspin can occur, such as
for an oil pump when backspin may occur due to the weight of the oil after a momentary power loss. The search starts from
the rotation direction specified in the direction command when the momentary power loss time is short. The search starts from
the opposite direction of the direction specified in the direction command when the momentary power loss time is long. The
rotation for the Speed Search is determined as follows:
[t] is the time from the momentary power loss to recovery.
5.2 b: Application
YASKAWA ELECTRIC SIEP C710636 04D U1000 Industrial MATRIX Drive Technical Manual 199
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Parameter Details